Read This Before You Have A Mammogram
In 2001, yet another mammography controversy was triggered by two Danish researchers who, after an in-depth assessment of all mammography-screening clinical trials, found the test leads to more aggressive treatment; increases the detection of cancers that do not progress; and might not save lives.  In this review, conducted by Ole Olsen and Peter Gotzsche of the Nordic Cochrane Centre, mammography-screened women showed a slight increase in heart-related deaths. The deaths are believed to be related to radiation therapy, a standard treatment for early breast cancer. (Read a 2009 update of this review.) Another controversy is brewing among researchers over the cause of the slight increase in breast cancer deaths among women in their forties shown in all mammography screening trials. This topic was addressed in two interviews conducted in 2002 by Maryann Napoli.

Mammography’s Risk to Younger Women

Last month, the Canadian National Breast Screening Study published follow-up results showing, once again, that mammography screening did not reduce the breast cancer death rate for women in their 40s (Annals of Internal Medicine, 9/3/02). The Study’s findings have challenged the prevailing belief that early breast cancer detection saves lives. Worse, they show that mammography screening leads many more women to be treated unnecessarily with mastectomy or radiation therapy. Though 40 more cases of non-palpable invasive breast cancer were detected in the mammography-screened women, their breast cancer death rate was no different from that of the women who did not get mammograms. Similarly, there were 42 more cases of ductal carcinoma in situ, a non-invasive cancer, detected in the mammography-screened women. This shows that mammography screening causes a significant number of younger women to suffer treatment-related harm without reducing their odds of dying of breast cancer.

Mammography proponents have criticized the Canadian Study ever since it first published results more than a decade ago. The Study now has 11 to 16 years worth of follow-up for women in their 40s. Its deputy director, Cornelia J. Baines, MD, was interviewed about the fact that—in the early years of this trial—there were more breast cancer deaths among women given mammograms. This was initially thought to be a statistical fluke when it first showed up. Now some researchers are having second thoughts.

MN: When you published your seven-year results, there were more breast cancer deaths (38) in the mammography-screened women, compared with those in the control group who had no mammograms (28). Were there any surprises now that you have 11-16 year results?

Dr. Baines: No, I knew by 1983 that more breast cancer deaths were occurring in the mammography-screened group rather than the control group. Of course, that’s not what we expected. When we started out, we were sure that we were going to show a major benefit. After all, the HIP Study [the first mammography trial conducted in the 1960s] had shown a benefit to women ages 50-69, and we assumed that the only reason a benefit wasn’t shown for younger women was that the mammography was archaic by today’s standards.

MN: When I interviewed you at the time you published the seven-year results, you said that the excess of ten breast cancer deaths was not statistically significant. I thought that meant it could be ignored.

Dr. Baines: You are quite right it’s not statistically significant, but what is disturbing is that this excess has happened in all screening trials in three different countries. 1985 was a landmark year for mammography screening trials. A Swedish study headed by Laszlo Tabar was published in The Lancet (4/13/85). When you read the abstract [summary] of that study, it says that women ages 40-74 showed a 31% reduction in breast cancer deaths. But if you look in the text of the article, you see that the number of deaths in the [small subset of] women in their 40s given mammograms was higher than in the control group. Similar results were observed in the Stockholm and HIP trials. The consistency of this trend demands further evaluation.

MN: Is anyone looking into it?

Dr. Baines: When we published our first results in 1992, it never entered my head that the people who have been promoting mammography would try to completely destroy the credibility of our study and ignore this phenomenon which had been clearly shown in Tabar’s study and which had also been shown in the HIP study. I started out saying that this needs investigating at the basic science level and believing that screening researchers would pay attention to these trends. Well, was I ever out to lunch. People, when they strongly believe in something, don’t waste time looking at evidence that challenges their beliefs. That’s just not human nature.

MN: Dr. Tabar is a recipient of an American Cancer Society award for his promotion of mammography screening and a teacher of Continuing Medical Education courses for American radiologists. He and the other mammography researchers might not want to look at the “why” behind the increase in breast cancer deaths, but haven’t some researchers begun to investigate a possible underlying biological mechanism for the deaths?

Dr. Baines: Yes, Michael Retsky, PhD, at Harvard Medical School, and Romano Demicheli and William Hrushesky. They studied the relapse patterns of 251 premenopausal women with node-positive breast cancer who had been treated only with surgery only and followed for 16-20 years. Retsky and colleagues found that the breast cancer mortality rates show two peaks: one occurs three years after diagnosis, the other at nine years, and after that, women seem to survive quite well. This, of course, corresponds with what we have been observing in mammography screening trials. Increasingly, researchers like Michael Retsky and Michael Baum speculate that something associated with the biopsy or surgery stimulates growth factors. In some women with micrometastases [undetectable spread of cancer outside the breast], these growth factors may stimulate the micrometastases, and the woman goes on to die. This is consistent with the suggestion made along time ago by Bernard Fisher [America's leading breast cancer researcher]—that micrometastases has already occurred in 90% of all breast cancers before clinical or radiological detection.

MN: Are you talking only about women in their 40s?

Dr. Baines: The finding was more prominent in younger women, but Tabar’s study showed a breast cancer mortality increase in older women as well.

SECOND INTERVIEW ABOUT MAMMOGRAPHY SCREENING

The following interview relates to the same topic. Michael Baum, MD, emeritus professor of surgery at University College in London, U.K., has been a breast cancer surgeon for 30 years. After leaving the Breast Screening Programme for the National Health Service in the southeast of England, Dr. Baum became an outspoken critic of mammography screening, particularly for women in their 40s.

In this interview, Dr. Baum is asked to comment on the new Canadian Study results. In doing so, he argues for a new paradigm for how and why breast cancer spreads. Dr. Baum champions the ideas of the famed Boston-based researcher Judah Folkman whose work is associated with angiogenesis. This is a natural process controlled by certain chemicals produced in the body, leads to the formation of new blood vessels. In adults, angiogenesis is involved in wound healing and menstruation. Angiogenesis can also have negative effects. Tumor growth is dependent on blood and oxygen supplied by these newly formed blood vessels, which also provide a means by which cancer cells can travel to distant organs and form new tumors.

MN: What do you make of the increase in breast cancer deaths shown in the women given mammograms in the early years of the Canadian Study?

Dr. Baum: I believe that it is a real phenomenon and not simply an artifact of this study. It appears in all the studies

MN: In all the studies, not just three?

Dr.Baum: Yes, to a lesser extent in all the other trials.

MN: There were more than twice as many cases of ductal carcinoma in situ [Latin for cancer in place] in the mammogram group. What do you make of that?

Dr. Baum: I’m very influenced by Judah Folkman’s work. He believes that in situ is probably not a good word, and we should call it latent cancer. These latent cancers, particularly in premenopausal women, are grossly overrepresented [in women given mammograms]–something like five times more, compared to what you would expect. That suggests if left to their own devices, these latent cancers might never trouble a woman. If you identify these latent cancers and biopsy them, you have traumatized the area. You immediately trigger the natural healing mechanisms, and natural healing mechanisms involve angiogenesis. So, effectively, the biopsy could be considered an angiogenic switch. You take a latent cancer that would never hurt a woman, biopsy it, turn on the angiogenic switch, and it ceases to be latent. A latent disease can become an aggressive disease.

MN: Is this true only for premenopausal breast cancer?

MB: You see this in other cancers. The most notorious is renal cell cancer. If you find a symptomless renal tumor by chance, and operate, [then] in no time the patient is riddled with metastasis. This happened to a dear friend of mine. I think that “angiogenic switch” might be an explanation. It’s really scary.

MN: Is that what you suspect is happening to some women with premenopausal breast cancer?

Dr. Baum: My explanation sounds a bit farfetched, but it is strongly supported by basic science that is coming out of the work on angiogenesis. There are profound cyclical changes going on in the premenopausal breast, and these changes can also be seen in a premenopausal cancer. So just by happenstance, you might get a surgical insult at a time in the menstrual cycle that favors the cancer cells. It’s all quite alarming.

MN: In the Canadian Study there were 71 cases of DCIS diagnosed in the women given mammograms, compared to 29 in the women not given mammograms.

MB: That tells you two things: 1) It emphasizes the quality of the study. If they were not detecting DCIS, then the screening zealots would say that the screening techniques in the Canadian Study were bad; 2) It demonstrates, yet again, that all screening programs will show an excess of cancers. And the excess is mostly DCIS. In women given a manual breast exam, only about 3% of cancers are DCIS; whereas in mammography-screened women, 20% of the cancers are DCIS.

MN: The breast cancer death rate was the same for both groups in the Canadian Study. Doesn’t that indicate that early detection is of no benefit to women with DCIS?

Dr.Baum: Yes, I think so. I don’t know if any lives are saved by screening, frankly. But the one argument about which I cannot be shaken is that women invited to screening should know these things. I was one of the people given the job of setting up a screening program in the 1987-88 in the U. K. Then it gradually dawned on me that this was state interference with public health, and it was coercion. I resigned in disgust from the National Screening Committee because they were intentionally deceiving women [about the harms]. They went on record saying, “We mustn’t let women know this because it might deter them from coming to screen.” So I decided to work outside the system to inform women about the truth of screening. I can see how some women, fully informed, would accept screening over the age of 50, but to promote mammography to women under the age of 50 is absolutely unethical.

MN: The American Cancer Society has been promoting mammography starting at age 40 for many years now.

Dr. Baum: Either the ACS is funded by the screening industry, or they’ve backed themselves into a corner and can’t admit they’ve been wrong all this time. The message is so seductive: “The secret to cancer is catching it early.” That’s rubbish. It’s so naive. The only thing that influences cancer mortality is better treatment, as far as I’m concerned. The word “early” has no meaning to a scientist. MN: Do you have an equivalent to the ACS in your country overselling the early detection message?

Dr. Baum: No, but we have “Black October,” which is what I call Breast Cancer Awareness Month, when lots of fine young women have these campaigns with catwalk models advising breast self- examination every month. And that gets across two false messages: 1) that self-examination is of any value; and 2) that the role model for breast cancer patients is a skinny girl of 23.

MN: Any parting thoughts about mammography research?

Dr. Baum: It ceases to be medical science now–it’s egos. A proper scientist should learn that you go through life being humiliated again and again. You have prepare yourself to admit you were wrong. That’s the very mechanism of science. Scientific truths are only temporary expressions of reality that serve us for the time being. There’s no such thing as scientific truth. It’s all an approximation to reality. A true scientist has to accept that his version of reality will be overturned in the fullness of time. If you can’t accept that, you’re not a scientist.