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Posts Tagged ‘mammography’

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Mammogram uproar

Posted by medconsumers on November 18, 2009

Ten years ago I opened my driver’s license renewal notice and out dropped a pink slip reminding me to have an annual mammogram. While it was touching to know that the New York State Department of Motor Vehicles cared about my breast health, I saw the pink slip as yet another example of over-the-top mammography promotion. (My husband has yet to receive any health instructions from the DMV.) When a test’s lifesaving benefit has been oversold to the public for over three decades—and the harms downplayed—any cutback in recommendations will be met with a firestorm of anger.

That’s exactly what happened yesterday when a highly respected organization recently broke ranks with others that issue screening guidelines and advised women at average risk for breast cancer to begin having regular mammograms at age 50, not age 40. The U.S. Preventive Services Task Force also changed two longstanding recommendations: women age 50 to 74 should have a mammogram every two years rather than annually (cuts down on the biopsies without altering the number of lives saved), and doctors should stop teaching women how to do breast self-examination (no benefit, more biopsies). Shock, horror, and condemnations followed the announcement in the media on Monday. Not a surprising reaction considering the advice to the public preceded the science.

The recommendation to start mammography screening at age 40 was premature to begin with, dating back to the early 1970s. Incredibly, it was based on one clinical trial conducted in the 1960s that found a 30% reduction in breast cancer deaths in the women over age 50 but no benefit for women in their forties. That clinical trial, known as the Health Insurance Plan of Greater New York study, had followed the participants for three to five years. Not unreasonably, public health officials at the time thought that the younger women in this study would eventually show a reduction in breast cancer mortality with longer followup. They didn’t bother to wait and the aggressive promotion of mammography took off after President Nixon declared the “war on cancer.” Thus began a nationwide campaign, sponsored by the American Cancer Society and the National Cancer Institute, urging women over the age of 35 to seek yearly mammograms complete with the overly optimistic message that early detection will save their lives.

Radiation exposure was the only acknowledged harm in this era, and it was usually dismissed as unimportant in comparison to the benefit of finding breast cancer early. By the 1980s, mammographic techniques had improved and the radiation exposure greatly reduced. A modest reduction in breast cancer deaths in younger women was found in some, but not all, clinical trials done in other countries. The largest trial intended to answer the question of mammography’s value to women in their forties found no lifesaving benefit. Basing its estimate on the trials that did find a benefit, the U.S Preventive Services Task Force concluded that one in every 1,900 women who undergo an annual mammography over a ten-year period will avoid a breast cancer death.

In 2001 the Lancet published the first evidence indicating that mammography screening leads to overtreatment without reducing mortality. The authors, both researchers at the Nordic Cochrane Centre, did an in-depth assessment of the data generated by all the randomized mammography screening trials. To this day the Cochrane researchers continue to reassess the research (read a 2009 update of their findings). What they have found is entirely counterintuitive and not confined to women in the forties. Mammograms can detect tiny cancers, but not all of them would become deadly or even produce symptoms if left untreated. Yet virtually all are treated aggressively because no test can accurately sort out the potentially lethal cancers from those that do not progress. Overdiagnosis and overtreatment are the terms for this problem, which was quantified in a study published recently in the British Medical Journal, showing that one in three cancers found on a mammogram would not become life-threatening. This should have been the major reason for the change in recommendations, but the media coverage frequently presented mammography’s major harm as the anxiety from false alarms and breast biopsies. As for the other major harm—radiation exposure—the USPSTF cites this estimate, “annual mammography of 100,000 women for 10 consecutive years would result in up to 8 radiation-induced breast cancer deaths.”

The USPSTF based its revised recommendations on the findings of a panel of experts made up of research physicians and most crucially, biostatisticians who quantified some of the harms as well as the benefit. Their task was to assess the evidence generated by the world’s gold standard trials, as well as observational studies. While we all hope that our physicians are familiar with the evidence supporting their advice, the sad reality is that many are not. Most simply follow the advice of organizations like the American Cancer Society and the American College of Obstetricians and Gynecologists. What’s more, it’s as hard for them to change their thinking as it is for us. Here’s just one example. From the professional advice given my daughter and her friends, I know that the long-discredited American Cancer Society recommendation for women to have a baseline mammogram in their late thirties continues to live on. (The ACS quietly withdrew this recommendation in 1992, but it takes time for the word to get out.)

Other sources of information:
If you want to make an informed decision about mammography, go directly to the scientific evidence instead of your doctor. Here’s a timeline for the key studies and previous failed attempts to raise the starting age for mammography which was published recently in the New York Times. This is a “summary of the evidence” from the randomized trials and observational or population studies (i.e., mammography done in the real world), which formed the basis for the USPSTF’s revised recommendations. And this is the National Cancer Institute’s summary of pretty much the same clinical trials (note that the first trial that justified the advice to start mammography at age 40 is described as being of “poor quality”), as well as population studies. The NCI summary is difficult to read, but this sentence from the summary is easy to understand, “Screening for breast cancer does not affect overall mortality, and the absolute benefit for breast cancer mortality appears to be small.” This applies to women who start mammgraphy at age 50 as well as those who started at 40.

Using the same data, researchers at the Nordic Cochrane Centre have produced a more understandable summary for women that is available on the Web (see link within this article). To increase your chances of having a mammography performed skillfully, read How to Select a Mammography Facility . And to reduce your chances of an inaccurate diagnosis, read “When to get a 2nd pathology opinion.”

Maryann Napoli, Center for Medical Consumers(c)

Postscript
Two days after the USPSTF issued its recommendations, HHS Secretary Kathleen Sebelius issued a statement distancing the Obama Administration from the new guidelines. In short, she told women to ignore them and claimed disingenuously that more research is needed. This is very disappointing to those of us who had high hopes that health care reform would mean that medical treatment and screening decisions, as well as cost-cutting measures, would be evidence-based. Once again, mammography’s evidence is clouded by politics. This time around, however, the politics make sense. No doubt, Secretary Sebelius did not want to derail the current health care reform efforts.

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When to get a 2nd pathology opinion

Posted by medconsumers on September 10, 2009

News Flash: American Cancer Society will warn of screening’s harms.

If I had my way, there would be a moratorium on mammography screening until doctors fully understand the natural history of what they’re looking for in the breasts of women without symptoms. The term natural history is medical jargon for knowing what would happen if breast abnormalities that look cancerous under the microscope were left untreated. At least one in every three breast cancers diagnosed via mammography screening would not progress; yet virtually all are treated aggressively as if they will. From the mammography screening clinical trials, we know that this includes not only ductal carcinoma in situ but also invasive breast cancers. Until about 40 years ago, it was thought that all cancers become lifethreatening if left untreated.

There are two breast pathologists in the U.S. who have spent their professional lives distinguishing the lethal from the nonlethal. Both have published widely on this topic. Both head second pathology opinion services that deal directly with women, who send in their tissue slides, mammograms…and their payments. In the usual situation, the pathologist and the patient do not interact. Dr. David L. Page, Vanderbilt University Medical Center, Nashville, TN, and Dr. Michael Lagios, St. Mary’s Hospital, San Francisco, CA, have, no doubt, spared many a woman the overtreatment that follows in the wake of any and all mammography screening activities. The overtreatment can involve unnecessary radiation therapy, unnecessary breast removal, and a lifetime of worrying about the recurrence of a cancer that would have been better off left undetected.

Every five or so years, I write about these two second opinion services. I decided to do it again when I heard recently from a long-time reader who was diagnosed with “ductal carcinoma in situ [DCIS] with scattered calcifications and atypical cells” at one of the top cancer centers in the U.S. She was told that a total mastectomy is necessary. Instead of following the advice, she paid for a second pathology opinion from each of the above experts who both assured her that she did not have DCIS and required only periodic follow-ups. When calling me about the revised diagnosis, she said, “My joy in learning that I didn’t need a mastectomy was overshadowed by the thought of so many women who are overtreated because of mammography screening.”

Each breast pathologist describes his service below:

David L. Page, MD Breast Consultants

“Our experienced professionals have reviewed over 50,000 consultative requests for pathologists, clinicians, and patients…. Our group has had a major interest in defining and diagnosing special breast conditions that are not truly malignant, but can recognize an increased risk of later breast cancer development, as well as minimally or low malignant lesions that may be successfully treated with local therapy alone.”

Michael D. Lagios, MD The Breast Cancer Consultation Service

“The Breast Consultation Service is designed to help self-referred women with newly diagnosed breast carcinoma or atypia with formal written review of their pathology slides, mammograms and other imaging studies. No physician referral or permission is needed to access this service.”

Disclosure: When writing this article I was surprised to see that Dr. Page has a 2004 article from our newsletter HealthFacts on his home page. It addressed the latest study about overdiagnosis and overtreatment, as well as the above second opinion services. I am flattered that Dr. Page thought enough of my article to post it. I am discouraged that it’s not out of date.

Maryann Napoli Center for Medical Consumers©

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Reduce your risk of breast cancer: Avoid mammograms

Posted by medconsumers on July 14, 2009

Want to know the best way to cut your chances of developing breast cancer? Stop having screening mammograms. Sure, the researchers who recently published a five-country study in the British Medical Journal would never express their findings in this manner. But read their results and decide for yourself. And keep in mind, many breast cancers detected by mammography will not become deadly or even produce symptoms if left untreated. Now it is known, one in three breast cancers fit that description.

Two Danish researchers conducted a systematic review of the breast cancer incidence in the seven years before a mammography screening program was introduced and the seven years after the screening program had been in full swing. The women in this review began having mammograms at the age of 50 years in the United Kingdom, Manitoba, Canada, New South Wales, Australia, Sweden and parts of Norway. The researchers were looking specifically at the number of women diagnosed with breast cancer after mass screening began. Although they expected a lower breast cancer incidence among the women as they grew older, this was not the case.

Here is what the researchers concluded, based on women who began screening at age 50 years. For every 2,000 women who undergo regular mammography screening over the next ten years, one will avoid a breast cancer death; 10 women will be diagnosed with a non-lethal breast cancer and treated unnecessarily; 10 to 15 women will be told they have breast cancer earlier than they would otherwise have been told, though this will have no affect on their prognosis (i.e., whether a woman’s breast cancer is found on a mammogram at age 55 or she finds it herself at age 65, her destiny is unchanged); and 100 to 500 women will have at least one “false alarm” that in about half the cases leads to a biopsy.

This review was conducted by Karsten Juhl Jorgensen and Peter C. Gotzsche, MD, of the Nordic Cochrane Centre in Copenhagen. Both have written extensively on the topic of overdiagnosis, which they define as “the detection of cancers that will not cause death or symptoms.” There is no foolproof way to determine which mammography-detected cancers do not progress from those that will. Virtually all are treated as if they will.

The lead author, Dr. Jorgensen, was asked by e-mail whether it is reasonable for a woman to decide not to have screening mammograms as a means of reducing her chance of having breast cancer. “In the light of our estimates of overdiagnosis, I would say that we now have to consider mammography screening as a major risk factor for getting a breast cancer diagnosis. And a preventable one, too,” he responded. “Of course, the breast cancers overdiagnosed through screening differ from the symptomatic ones by being non-lethal, but the individual woman cannot know this and the remaining consequences are the same (the surgery, radiotherapy and psychological stress).”

This is not the first time mammography screening was shown to cause more harm than good. Overdiagnosis and overtreatment were first identified in a 2000 systematic review of all seven trials worldwide that had randomly assigned women to receive mammograms or not. That review, which originally appeared in the British journal Lancet, has been updated as a Cochrane review.

Safest course of action? Seek medical attention at the first sign of a breast symptom.

Maryann Napoli, Center for Medical Consumers(c)

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Make an Informed Decision about Mammography

Posted by medconsumers on March 1, 2009

A Rare Honest Explanation of the Pros and Cons of Mammography Screening

Printed materials designed to inform women about the need for regular screening mammograms are notorious for not mentioning the harms as well as the benefits of early breast cancer detection. A ground-breaking exception has just been made freely available at the Web site of the Nordic Cochrane Centre of Denmark (click here to view leaflet).

The “leaflet” comes from a research team led by Peter C. Gøtzsche, DrMedSci, director of the Nordic Cochrane Centre, Copenhagen, which found that the major risk to screening mammograms is overdiagnosis—that is, unnecessary treatment for a cancer that would never progress. As the new leaflet puts it, “If 2,000 women are screened regularly for 10 years, one will benefit from the screening, as she will avoid dying from breast cancer. At the same time, 10 healthy women will, as a consequence, become cancer patients and will be treated unnecessarily.” No test can accurately distinguish the cancers that will become aggressive from those that will remain dormant or develop very slowly.

This project has a history that dates back to 1999 when Dr. Gøtzsche was asked by a Danish government agency to conduct a systematic review of all mammography screening trials worldwide. The agency wanted to know what the research had actually proven because doubts had been raised about the benefit of screening. This review was eventually published in The Lancet and in the Cochrane Library in 2001, and according to the requirement of the Cochrane Collaboration, it was updated in 2006 and is currently being updated again. The conclusion of the Cochrane review is: “It is not clear whether screening does more good than harm.”

Two of the seven trials in this Cochrane review, one conducted in Sweden and the other in Canada, found no decrease in breast cancer mortality among women given regular mammograms. The other five trials found small reductions in breast cancer mortality among those who had received mammograms. The seven trials had a combined total of about 500,000 women in North America and Europe who had been randomly assigned to receive regular mammograms or not.

The new leaflet’s benefit/harm calculations are based on the combined results of these trials—for every 2,000 women who undergo mammography screening over the course of ten years, one will avoid a breast cancer death and ten more will be treated unnecessarily for a nonprogressive cancer due to overdiagnosis.

The Cochrane review was not well received in this country because it contradicts the prevailing medical wisdom about mammography screening and dared to calculate harms.

In time, Dr. Gøtzsche and colleagues went on to assess the quality of the printed information given to women in six countries with publicly funded screening programs. Such countries inform women of the need for mammograms via “letters of invitations” to be screened. “The major harm of screening, which is overdiagnosis and subsequent overtreatment of healthy women, was not mentioned in any of 31 invitations. Ten invitations argued that screening either leads to less invasive surgery or simpler treatment, although it actually results in 30% more surgery, 20% more mastectomies, and more use of radiotherapy because of overdiagnosis,” wrote Gøtzsche and colleagues in a recent issue of the British Medical Journal.

No such survey of U.S. mammography information sources has been conducted, though a 2000 survey of American women’s attitudes toward this screening test showed 94% doubt the possibility of cancers that do not progress.

To read what is arguably the first honest mammography information for women written by health professionals, go to the Web site of the Nordic Cochrane Centre (www.cochrane.dk), which also provides free access to the Cochrane review. The information is currently being translated into Spanish, Portuguese, Polish, Norwegian, Swedish, Finnish and Icelandic, and there are also plans for German and French translations.

Maryann Napoli, Center for Medical Consumers© March 2009

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MRI Scans and Mastectomies

Posted by medconsumers on September 1, 2008

Preoperative MRI Linked to Increase in Mastectomies at Mayo Clinic

Magnetic resonance imaging, or MRI, made news last spring at a meeting of cancer doctors when a Mayo Clinic oncologist reported that the use of this diagnostic technology appears to increase the number of women who are choosing mastectomy over breast-conserving surgery. The finding is based on a study of early-stage breast cancer patients treated at the Mayo Clinic in Rochester, MN.
The rate of mastectomy in the U.S. had been declining steadily since the mid-1980s when a landmark national trial proved it to be no more lifesaving than breast-conserving surgery. For example, 36% of the women treated at the Mayo Clinic had a mastectomy in 2002, down from 45% in 1997.

Matthew Goetz, MD, the medical oncologist who presented these findings at the meeting of the American Society of Clinical Oncologist, called attention to the change that began to occur once preoperative MRI was introduced. The rate of women given this imaging procedure preoperatively went from 11% to 22% between 2003 and 2006. During the same period, the mastectomy rate rose from 30% to 43%.

MRI is sometimes recommended in addition to a mammogram, especially for women with dense breasts and/or a genetic predisposition to breast cancer. The newer technology has several advantages over mammography, such as no radiation exposure, no compression of the breast, and a sharper imaging that identifies more abnormalities. The downsides of MRI include high cost and sharp imaging that causes a high rate of false alarms (19% in first year and 9% in the second, according to one study).

The Mayo Clinic findings do not prove that MRI directly caused the increase in the number of women choosing mastectomy. Nor were women or doctors asked about their decision-making process. Referring to MRI’s ability to find tiny lesions that may or may not be cancer, Dr. Goetz said, “What we don’t know from this study is whether the higher rate of mastectomy observed in our patients undergoing MRI leads to greater anxiety for the patient and physician, thus leading patients and physicians to choose mastectomy over lumpectomy.”

In a recent issue of the Journal of the National Cancer Institute, Dr. Goetz elaborated on this theme, “I wonder whether patients reach a threshold where they are unwilling to deal with the uncertainty of future imaging and biopsies,” he said. “They are tired of a physician saying, ‘We’re not sure, follow up in six months with a repeat test,’ and so those patients may say, ‘Thank you very much, but let’s just proceed with a mastectomy.’”

For More Information About MRI and Other Cancer Tests:

Go to www.cancer.gov, the Web site of the U.S. National Cancer Institute (type: MRI in the search box at the top of home page).

This Web site is also a good source of information about all cancers and their respective ltreatment options by stage. There is a patient’s version for each cancer, which is billed as “less technical,” but it only describes the treatments options. To find out how good the supporting scientific evidence is for these treatment options, go to the “health professional” version. You can click into the abstracts of the clinical trials that produced the supporting evidence. The health professional version also ranks the quality or strength of the evidence. Or, call 1(800) 4-CANCER.

Maryann Napoli, Center for Medical Consumers ©
September 2008

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How to Select a Mammography Facility

Posted by medconsumers on July 1, 2008

Can women do anything to improve their chances of receiving an accurate interpretation of a screening mammogram? A new study found that there are several important characteristics to look for when selecting a mammography facility. The finding is based on a survey of 44 U.S. mammography facilities published last month in the Journal of the National Cancer Institute.
To learn how women can act on the results of this study, Maryann Napoli, Center for Medical Consumers, interviewed one of its co-authors, Joann G. Elmore, MD, Professor of Medicine, Adjunct Professor of Epidemiology, University of Washington School of Medicine, Seattle.

MN: Doesn’t the physician usually choose the mammography facility?

JGE: Most often women see their primary doctors and that doctor will refer them to a mammography facility that is linked with the primary care office.

MN: So women don’t actually do the choosing?

JGE: Mammography screening is a unique medical test in that women can refer themselves. There are mobile vans going around the country, stopping at work sites. I don’t know the actual number of women who self refer, but I suspect many women are actively involved in choosing mammography facilities.

MN: You have co-authored dozens of mammography-related studies. I recall being shocked by your first one, published in The New England Journal of Medicine in 1994. You found that experienced board-certified radiologists interpreting the same images often come to different conclusions about the presence or absence of breast cancer.

JGE: For many years I’ve been trying to figure out why there is so much variability in the interpretation of mammograms. Then we went on to identify characteristics of the patients that put them at risk of having an inaccurate exam. Some characteristics you cannot change like having dense breasts, and some you can change. For example, menstruating women can make sure not to schedule a mammogram around the time of their periods when the breasts swell and become tender. A few studies show accuracy is lower at this time.

MN: And now you’ve taken on the characteristics of the mammography facilities in your latest study.

JGE: Yes, I have been working in this area for 15-20 years, but I had never really asked the question: Does it matter which facility women choose? We found that facilities that have breast imaging specialists on their staff had a higher degree of accuracy.

MN: Don’t all facilities have breast imaging specialists interpreting the mammograms?

JGE: No, in some facilities mammograms are interpreted by general radiologists who do not have specialty training in breast imaging. And these radiologists interpret the minimum number [of mammograms] required for accreditation, but they may also interpret chest x-rays, MRI scans, ultrasounds, etc. Mammography may be a small part of their clinical workload.

MN: So women should ask this question of the facilities on the phone, prior to making an appointment: Do you have a breast imaging specialist on the staff? I know this is an awful question but do you really think women will get an honest answer from facilities that have only general radiologists reading their mammograms?

JGE: Well yes, if women ask the question this way: Do you have a radiologist that spends more than 50% of the time working in breast imaging? That’s pretty clear-cut. That’s how we define a breast imaging specialist in our study.

MN: What else did you find that women should ask about the facility?

JGE: They should ask whether the facility conducts audit reviews two or more times a year. Our study found higher accuracy among the facilities that review their audit data with the radiologist on a regular basis. This finding makes sense to me because the radiologists are learning from the prior history and probably improving the quality of their interpretations.

MN: Audit reviews are a form of quality control. The facility should compare the mammogram interpretations with the results of the breast biopsies in order to regularly test the accuracy of the radiologists’ decisions.

JGE: If you read the fine print of the Mammography Quality Standards Act, you’ll see that the facilities don’t have to show the audit results to the individual radiologists.

MN: That’s disturbing. Why collect audit information if the facility doesn’t show it to the radiologist?

JEG: Yes, as a physician, I believe that we have the opportunity to improve when we get feedback.

MN: That changes the second question women should ask when choosing a facility. It should be: Does your facility do audit reviews at least twice a year, and is the radiologist routinely given the results of these reviews?

JEG: Yes.

MN: You did not find volume to be important to accuracy. One would think that the more images a radiologist reads, the more likely he or she will make accurate interpretations.

JGE: Many studies have evaluated whether high volume is associated with performance, and there’s an assumption that really high volume by the radiologist is good because it means that the radiologist has a lot of experience. But like all areas of life, it’s more difficult than that. It’s possible that the facility could have high volume, but the facility might not be collecting and reviewing the audits and therefore not following up on those many thousands of patients whose mammograms have been interpreted.

MN: What’s the definition of high-volume?

JGE: There have been a few studies, but many of them have contradictory results. In the U.S., radiologists must do a minimum 480 mammograms per year, as required by law.

MN: That doesn’t sound like much.

JGE: In Europe, the minimum in some countries is 5,000 cases a year. But the question is: Are some countries doing better because they have higher volume? The published studies have contradictory results. There’s an ongoing study funded by the American Cancer Society and the National Cancer Institute. It will be helpful to see if they can clarify this at all.
MN: What are you working on now? What are the other major unanswered questions about mammography that should get research attention?

JGE: I’m continuing my research efforts aimed at improving the quality of breast cancer screening and detection. I am investigating the efficacy of new technology, such as digital mammography and computer-aided detection, and how we can improve our communication related to mammography.

MN: Mammography screening has been aggressively promoted to women ever since the early 1970s. It’s interesting to see how long it takes to get some basic questions answered. You are to be congratulated for being in the forefront of mammography screening research and for continuing to ask the research questions that will lead to more improvements. See Mammography Leaflet from the Nordic Cochrane Centre.

Maryann Napoli Center for Medical Consumers ©
July 2008

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Only One in 2000 Women Benefit from Mammography

Posted by medconsumers on December 1, 2006

Over the 31 years of publishing our newsletter, we have reported frequently about the lack of honesty in the mammography-screening information directed at women. Whether it comes from the American Cancer Society or a family physician, the information tends to be heavy on the lifesaving benefits and light on potential harms.

Here’s something a woman is unlikely to hear: For every 2000 women* who go for mammography screening throughout a ten-year period, one woman will have her life prolonged. BUT ten additional healthy women, who would not have received a breast cancer diagnosis had they avoided mammography screening, will be treated unnecessarily for a breast cancer that would never have become life-threatening. And more than 200 women will experience significant psychological distress for many months because of false-alarm findings on a mammogram.

This important information, so crucial to a woman’s informed decision-making, comes from a recent update of a 2001 Cochrane Review of the world’s major mammography screening clinical trials with a combined total of a half a million women. In all seven trials, which form the basis of the U.S. screening recommendations, women were randomly assigned to receive screening mammograms or not. These trials, conducted in North America and Europe, were published many years ago, but researchers continue to argue over their interpretation and conclusions.

* These statistics apply to women, aged 50-69 years. Odds of lifesaving benefit are even smaller for women in their forties.

Original Review in 2001
The 2001 Cochrane Review of these trials was co-authored by Peter Gotzsche, MD, of the Nordic Cochrane Centre in Copenhagen, as is the 2006 update published recently in the Cochrane Library. The original review triggered a prolonged debate in the American media in 2001-2002 after The Lancet published a summary of its results. The lifesaving benefit of mammography screening was shown to be far more modest than previously thought and the harms had been greatly underestimated.

The Cochrane Review also found that the mammography-screened women in the trials had more mastectomies, more lumpectomies, and many more cases of ductal carcinoma in situ (DCIS) than the women who were not screened. Although most cases of DCIS, a tiny non-invasive cancer within the milk duct, do not progress, they were—and in some parts of the country, still are—always treated with breast removal. Now radiation therapy is the more common treatment for DCIS.

In the two trials judged to be of the highest quality by the Cochrane reviewers, there were 30% more cancers in the mammography-screened groups than in the unscreened groups and 31% more mastectomies and lumpectomies. Yet surprisingly, in both of these trials, conducted in Canada and Malmo, Sweden, respectively, mammography screening did not reduce the rate of breast cancer deaths. The other five trials, judged to be of inferior quality by the Cochrane reviewers, did show a modest reduction in breast cancer deaths.

Old Trials, New Data
You might wonder why we are still learning new information from these seven trials, which were conducted between the 1960s and 1980s. The answer lies in the Cochrane reviewers’ thorough assessment of the enormous amount of data that was originally withheld and, in some cases, continues to be generated by these trials. The data, it should be noted, were requested by the Cochrane reviewers.

The long-term data provided by the Canadian trial are a case in point. Mammography’s ability to detect many more cases of DCIS has long been known. Not until this trial published 11- to 16-year follow-up results for women in their forties did it become evident that mammograms also detect non-palpable invasive breast cancers that do not progress. This means that some breast cancers can begin to invade the surrounding tissue, but go no further.

This was demonstrated by the Canadian trial results: There were 43 more invasive breast cancers and 42 more cases of DCIS in the women who underwent mammography screening, compared to those who did not. Yet 16 years later, the breast cancer death rate of both groups was exactly the same. (It is likely that there were just as many breast cancers of both types in the women not given mammograms, but these women benefited from being unaware of them.) Currently, doctors are not able to determine which cases of DCIS and invasive cancer will not progress to become life-threatening. All are treated as if they will be lethal.

Bottom Line: Mammography screening was introduced 35 years ago to reduce the rate of breast cancer deaths by finding and treating breast cancer before it can be felt by a woman or her doctor. even trials have produced contradictory results about the reduction in deaths. And some of these trials found that mammography can detect non-palpable breast cancers—both invasive and noninvasive—that do not progress. All are treated as if they will. For the first time, the benefit and harms have been quantified for women who want to make an informed decision. Based on the combined results of these trials, the Cochrane reviewers produced the one in 2000 women will have her life-prolonged estimate stated at the beginning of this article.

“Women, clinicians and policy makers should consider the trade-offs carefully when they decide whether or not to attend or support screening programs,” concludes the updated Cochrane Review, which was originally commissioned and funded in 1999 by the Danish Institute for Health Technology Assessment and the (Danish) National Board of Health.

 

Maryann Napoli, Center for Medical Consumers ©
December 2006

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Breast Cancer Awareness Month: Read This Before You Have a Mammogram

Posted by medconsumers on September 1, 2005

Mammography Screening—Both Good and Bad News

Mammography screening seems destined to spawn controversial study results, as it has in the last few months. And its role in reducing the breast cancer death rate will remain the subject of heated debate among researchers for a good long time. The U.S. breast cancer death rate has declined 20% since 1990, as it has in other western countries. But it is not clear whether this can be credited to mammography, treatment improvements, or simply greater awareness among women that breast tumors should be promptly examined. What has become increasingly clear is this: Mammography screening harms more women than it helps.

That’s not the message that goes out to women via the media and their doctors. Of the three recently published mammography screening studies, the most media attention went to the one that seemed to equate the improvements in breast cancer survival with the increase in the proportion of women now diagnosed with small breast cancers. That was the take-home message from a CNN TV interview with Clifford Hudis, MD, a co-author of this study published last month in the journal Cancer.

With his colleagues at Memorial Sloan-Kettering Cancer Center, New York City, Dr. Hudis reviewed the early-stage breast cancers diagnosed in the U.S. over a 24-year period, from 1975 to 1999. The statistics came from the government’s database that draws from nine cancer registries across the country considered to be broadly representative of the U.S. population.  Information concerning more than ¼ million breast tumors from the same population was also available to the researchers. The upshot: Many more small breast cancers were diagnosed in 1999 than were diagnosed in 1975.

Certainly sounds like good news, and that’s how it played out in the Wall Street Journal and other media. Yet despite the messages conveyed in the CNN TV interview, Dr. Hudis’s study did not determine why the breast cancer death rate went down. It simply found a greater number of women diagnosed with breast cancer in recent years had small tumors.

It is unclear why Dr. Hudis would misrepresent his own study and leave CNN viewers with the impression that mammography and breast self-examination (BSE) are largely responsible for the decline in breast cancer deaths. Let’s put aside for the moment Dr. Hudis’s discredited belief in BSE, as two trials showed the practice leads to unnecessary biopsies with no discernible benefit.

Instead, a hard look at the nation’s increase in small cancers is long overdue. The topic is too complicated for a four-minute TV interview. The breast cancer death rate may be going down, but there has also been a steady annual increase in the number of women diagnosed with breast cancer over the last two decades. The increase is generally acknowledged to be related, at least in part, to mammography screening. This is not entirely good news. Mammography screening may prolong life for some women, but it also causes many more women to be diagnosed and treated for cancers that they would be better off not knowing about. Not all cancers are deadly even if left undetected.

“Screening mammography is great for finding small cancers. But finding small cancers is not necessarily good,” according to Donald Berry, PhD, Chair of the Department of Biostatistics and Applied Mathematics at the University of Texas M.D. Anderson Cancer Center. In an e-mail interview, Dr. Berry explained that breast cancer comes in several different forms. “Some cancers are lethal and others are not. Non-lethal cancers tend to be smaller, and they tend to grow more slowly.” Dr. Berry recently co-authored a study that showed that breast cancers detected by mammography tend to have the best prognosis (excellent chance of recovery with treatment), even when the cancer has spread to the lymph nodes. The authors advise doctors to take that into consideration when recommending treatment.

Dr. Berry and colleagues assessed the outcomes of two major mammography screening trials that together included over 150,000 women, singling out those who eventually developed breast cancer. More cancers—both invasive and noninvasive (ductal carcinoma in situ)—were detected among mammography-screened participants, as compared with those not given mammograms.

“Screening mammography finds a greater proportion of non-lethal cancers than do other methods of detection. Unfortunately, it is not possible to perfectly identify which cancers are lethal. So we treat them all. Consequently, screening leads to overdiagnosis and excessive treatment,” Dr. Berry explained, referring to surgery, radiation, hormonal therapy, and chemotherapy that some women could have avoided without risking their health.  Unfortunately, women have been led to believe the opposite—that mammography leads to less drastic treatment.

One of the trials assessed by Dr. Berry and colleagues found the breast cancer death rate among the women given mammograms was no different from that of the women not given mammograms. This is after 16 years of followup. The finding clearly suggests that mammography is not only useless but harmful to a significant number of women. There were 82 additional breast cancers* (half were invasive and half were noninvasive) in the women given mammograms. In other words, 82 of the mammography-screened women were treated for a cancer, including invasive cancer, which would not have produced symptoms or become life-threatening.

No other cancer screening test has been as well studied as mammography. Of the seven such trials conducted worldwide, two found no difference in the breast cancer death rate between the mammography-screened women and those not given mammograms. In a systematic review of the seven mammography trials conducted in 2000 by the Cochrane Collaboration, the two trials that found no life-prolonging benefit to mammography were determined to be superior in terms of quality than the five trials that showed a modest benefit to mammography. (None were without flaws.) The Cochrane Review’s conclusion: “Screening is unjustified.”

The merits and flaws of these seven major trials have dominated the controversies over the value of mammography. Little is known about the quality of mammography screening in the real world. Women who participate in clinical trials are given high-quality mammograms that are read by experienced radiologists. In other words, it is mammography under the best of circumstances. Not enough research attention has been given to the question of how women fare when given mammograms in the everyday practice of medicine. That was the point of a new study led by Joanne Elmore, MD, School of Medicine, Harborview Medical Center, University of Washington, Seattle.

With colleagues at several medical centers, Dr. Elmore looked at the medical records of women enrolled in six health plans around the country. They singled out the women who died from breast cancer between 1983 and 1998, an era that followed major improvements in mammographic techniques. 1351 women with breast cancer (aged 40 to 65 years) were matched with 2501 cancer-free women who were the same age and with the same level of risk for breast cancer.

Dr. Elmore and colleagues compared the screening practices (mammography and a physician’s breast exam) of the women who died of breast cancer with the high-risk women who were still alive. High-risk was defined as having a family history of breast cancer or a breast biopsy, as noted in the medical records. If screening reduces the rate of breast cancer death, the researchers expected to find that the women who died of breast cancer had undergone less screening then the women still alive. In fact, there was no difference between the two groups.  “Our findings suggest that breast cancer screening in the community was minimally effective in preventing death,” concluded Dr. Elmore and colleagues. Results were published in the Journal of the National Cancer Institute.

In the editorial that accompanied this study, Russell Harris, MD, University of North Carolina, Chapel Hill, gave several reasons why screening may be making “a smaller contribution” to the reduction in breast cancer deaths than the major trials have led us to believe. “Better treatment may mean that screening is less necessary than it was previously, because treatment of later stage cancers may still be effective.”  He also cites the fact that women today are more likely to have breast lumps “found accidentally” promptly examined by a health professional. Here Dr. Harris is referring to women finding tumors while in the shower, as opposed to finding them while doing BSE.

Women continue to get one-sided information about mammography (“it will save your life”) and little about its harms (unnecessary treatment). This was reflected in a survey of American women’s attitudes toward this technology in 2000. Only 6% reported that they knew about cancers that do not progress or become life-threatening.

For an international perspective on the accuracy of the mammography information dispensed to women via Web sites in eight countries, a 2003 survey was conducted by Karsten Juhl Jorgensen, MD, and Peter C. Gotzsche, MD, of the Nordic Cochrane Center in Copenhagen. They assessed 27 Web sites that were sponsored by governments, professional organizations, and consumer advocacy groups.

Jorgensen and Gotzsche, whose findings appeared last year in the British medical journal, BMJ, concluded, “The information material provided by professional advocacy groups and governmental organizations is information poor and severely biased in favor of screening…and failed to mention major harms.”  On the other hand: “Web sites of consumer groups were more balanced and comprehensive.” The three consumer advocacy groups with the balanced information are all U.S.-based: The National Breast Cancer Coalition (www.stopbreastcancer.com), Breast Cancer Action (www.bcaction.org) and the Center for Medical Consumers (www.medicalconsumers.org).

Based on the findings from seven clinical trials, Jorgensen and Gotzsche describe the cost to women in terms of unnecessary treatment. For every 1000 women who undergo mammography screening for ten years, they report, one woman will have her life prolonged; five additional women will receive an unnecessary cancer diagnosis and treatment; and three women will have a benign tumor biopsied.

“Whether this is too high a price to pay is open to debate,” wrote Jorgensen and Gotzsche, “but if women and policy makers are not informed of this balance between major benefits and major harms—which they have not been so far—then there cannot be any discussion or rational decision making.”

Bottom Line: Mammography-detected breast cancers have the best outlook. The screening test also leads to the detection and treatment of breast cancers that would never become life-threatening. Mammography’s role in the nation’s declining breast cancer death rate remains unclear. At best, it appears minimal. Women are not receiving honest information about mammography’s harms.

*There were 592 cases of invasive breast cancer and 71 noninvasive breast cancer in the approximately 25,000 women given mammograms, as compared with 552 invasive and 29 noninvasive breast cancers in the approximately 25,000 not given mammograms. The women were age 40 at the start of the trial. Only half of all noninvasive cancers, also called ductal carcinoma in situ, are likely to become invasive, but all are treated as if they will. This trial indicates that invasive cancers do not always progress and become lethal.

Maryann Napoli, Center for Medical Consumers ©

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2004 Update on Summary of the Evidence

Posted by medconsumers on January 26, 2004

It is not clear whether the benefits of mammography outweigh the risks for women in their 40s. Not all of the clinical trials have consistently shown that mammography screening reduces your chances of dying of breast cancer. Of the seven large trials in which women were randomly assigned to have periodic mammograms or not, five trials showed a lower breast cancer death rate among all mammography-screened women, ages 40 to 69 years. But two found no lifesaving benefit to mammograms for women of any age. Pool the results of all seven trials for women ages 50 and older, and the breast cancer mortality for those having mammograms drops by 22% in relation to the unscreened women. Pool the results for women in their 40s, and their breast cancer mortality drops by 15% in comparison to their counterparts not given mammograms. Here’s what that means to you as an individual: If you are in your early 40s, your risk of dying of breast cancer in the next ten years is 0.3%. If you start mammograms and continue having them for the next ten years, you will, at best, reduce that risk of dying of breast cancer by one-tenth of 1%.

This modest benefit should be weighed against mammography’s potential for causing some women to undergo unnecessary treatment with radiation therapy or mastectomy. Clinical trials have documented mammography’s ability to find cancers that will never produce symptoms or become life threatening. One of the two trials that found no mortality reduction benefit for mammography was conducted in Canada . It is the only one specifically designed to answer the long-standing question of mammography’s value to women in their 40s. All the women in this trial were given skilled professional breast exams, but only half of them had regular mammograms.

There were 40 more cases of nonpalpable invasive breast cancer and 42 more cases of ductal carcinoma in situ (a non-invasive cancer that some experts believe is just a risk factor for breast cancer) detected in those screened with mammography than in those given solely a professional breast exam. Contrary to expectations, their rate of breast cancer deaths after 13 years was no different from that of the women not given regular mammograms. This not only shows that the technology leads to the unnecessary treatment of some cancers that would have remained dormant, but it also detects a type of breast cancer so slow-growing that women will be successfully treated regardless of when tumors are found.

An in-depth review of all seven mammography-screening trials, conducted in 2001 by the Nordic Cochrane Centre, concluded that the two showing no breast cancer mortality-reduction benefit to mammography were of a higher quality than the five trials that did. This review also looked at the question of whether mammography saves lives when deaths from all causes are taken into account. This is an important consideration because some women die of breast cancer treatment-related causes. For example, some trials showed an increase in cardiovascular deaths after radiation therapy among younger mammography-screened women. The Nordic Cochrane Centre concluded that mammography screening does not reduce the overall death rate. This conclusion has been widely challenged by other researchers; it is important for women to know about it nonetheless. Although mammography screening is thought to lead to less drastic treatment, the Nordic analysis of all seven trials found 20% more mastectomies among the women given mammograms.

Unnecessary breast biopsies are another well-known consequence of mammography screening. The rate of false alarms, causing emotional trauma, is particularly high among women under the age of 50. If 10,000 women under the age of 50 have a mammogram, 640 will have an abnormal mammogram and 1,280 extra tests will be performed on them. 150 will go on to have a surgical biopsy, of which 17 turn out to have invasive breast cancer. However, only one death, at best, will have been prevented.

Keep in mind that the statistics quoted here come from clinical trials in which high-quality mammography screening is done under the best of circumstances, and results may differ where it concerns mammography as it is performed and interpreted in the day-to-day practice of medicine. While your health practitioner may strongly recommend them, the decision whether to undergo regular mammograms is entirely up to you.

Maryann Napoli
January 26, 2004

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Mammography Media Survey

Posted by medconsumers on January 1, 2003

Survey of U.S. Media Coverage of the Review of Mammography Trials:
An Opportunity to Educate Consumers About the Risks of Detecting Ductal Carcinoma in Situ?

See poster for 2002 Cochrane Colloquium, Stavanger, Norway.

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