by Lanie Melamed, Ph D

In my lifetime, mammography has been viewed as the standard and most effective method to screen for breast cancer and thus to extend women’s lives. However, like so many other breakthroughs in science, years later questions and doubts are raised—in this case, about the safety and reliability of mammography. Last year, a Swedish study proposed that breast cancer screening with mammography might be unjustified—that thorough physical exams are equally effective in preventing death. Once again, women are faced with contradictory information crucial to decisions they must make about their health care. The mammography debate started as early as the 1950’s when several ‘dissident’ doctors questioned the belief in mammography for early detection coupled with a growing emphasis on profit as a determinant of policy. How comforting it would be to look toward government agencies for impartial and nonpartisan answers to such questions!

The ideas explored in this essay reflect my own thinking based on a personal quest, my reading articles on and off the internet, discussions with others, and a hard-won understanding of how the cancer establishment functions. This article discusses the value of routine mammography screening only. There is no doubt that diagnostic mammography in response to suspicious symptoms, genetic abnormality or other recognized risk factors is still the best tool we have. For several years I have been agonizing about whether to submit myself to another mammogram. This question first arose after I read Dr. Samuel Epstein’s book, The Breast Cancer Prevention Program (1997) in which he outlined the dangers of mammograms and listed six alternative screening methods—each of which, to date, has been insufficiently researched.

A paper written in 1998 by one of BCAM’s founders, Sharon Batt, summarized the benefits of mammography at a time when BCAM was considering affiliation with the Quebec government screening program. BCAM has been represented on the Quality Control Committee (CSQ) of the Breast Cancer Screening Program in Quebec (PQDCS) since 1997. Sharon wrote

• Mammography is an effective intervention in screening women between the ages of 50 and 69. Studies demonstrate that mammograms reduce breast cancer mortality for this age group by as much as 30% (These figures are currently being re-evaluated.) This did not necessarily apply to women younger than 50 due to the density of their breast tissue.
• An up-to-date government-sponsored screening program could foster quality control in standards, staff and equipment across the province and could provide equal access to women in communities that are not always well-served by the medical system.
• If encouraged, community participation could influence the development of research, screening methods and procedures.
• A screening program should never be viewed as a substitute for research into the primary causes of cancer. Although early detection is better than late detection for some types of breast cancer, prevention is best.

Potential problems were foreseen and others have since emerged. These include...

• Mammography is painful and frequently leads to psychological stress, unpleasant and unnecessary follow-up biopsies and surgical procedures. Accurate analysis depends in large part on the expertise of the radiologist reading the results. (One study involved ten radiologists interpreting 150 mammograms; they reached the same conclusion in only ten cases!)
• Results are often misleading, resulting in “false negative” and “false positive” readings. In the former, cancer is present but not detected; in the latter, the diagnosis is cancer but surgery reveals a false diagnosis. A woman between the ages of 40 and 69 who receives routine mammograms over a ten-year period runs a 50/50 chance of being called back for additional tests that will ultimately reveal that she is cancer-free. Conversely, studies indicate that mammograms miss an average of 30% of tumours in women younger than 50, and 20% in women over 50.
• The Quebec screening program is intended for women aged 50 to 69. New evidence suggests that mammograms do not reduce deaths, even in this age group. To date there is little information about the impact of mammographic screening for women 70 and over. (One study suggests that mammography has limited value for this age group since cancer tends to be slower growing in older women.)
• Mammography has resulted in the overdiagnosis and treatment of ductal carcinoma in situ (DCIS). Studies indicate that 80% of microscopic lesions within the milk duct will never become invasive if left untreated. Lamentably, thousands of women have undergone unnecessary surgery, radiation and sometimes chemotherapy after a diagnosis of DCIS. For every woman who receives a life-saving mammogram, three receive the false diagnosis of a potentially fatal disease.
• According to a Canadian study, conducted over a 13-year period, early detection of DCIS proved to be no advantage. The more significant factors were the nature of the tumour, whether it was fast, medium or slow-growing, and the woman’s ability to fight off the disease. Fast-growing tumours will likely spread before they can be excised, and slow-growing ones will not result in death. Early detection was beneficial only in cases of moderately aggressive tumors that could be caught and treated in time.
• Breast X-rays involve ionizing radiation which is a recognized cause of breast cancer. All radiation has a cumulative effect and is stored forever in the body. The greater the radiation exposure/dosage over a lifetime, the greater the risk of radiation-induced cancer. Despite the fact that the amount of radiation used in mammography has decreased significantly over the past twenty years, the cumulative risk remains problematic. The radiation dose from a single four-view film screening, using a grid, is approximately. 02 rads. (A rad is a measure of radiation exposure.) The chief technician at one of Montreal’s better radiology centres reports that the dose varies according to the number of X-rays required. This can depend on the age of the woman, her health history, the size and density of her breasts, the nature of her breast tissue, whether she is on hormones, and the condition of the machine.
• Rarely mentioned in the literature is the danger that compressing the breast so forcefully could result in the break-up of small blood vessels, enabling cancer cells to spread to other parts of the body. The studies we have provide contradictory and incompatible information. To begin with, we should ask who is conducting the study and what is their interest in doing so. Most hospitals, care centres, states and nations record statistics that measure different age groups, time frames, types and length of treatments, making it difficult to assess and compare studies from region to region. Eager to hit the press, many studies are terminated before adequate data has been collected, thus confusing mortality rates with data about women who survive for five years or more after the initial treatment. The phrase “follow the money” is not far-fetched.

Are there reliable alternatives?
Dr. Epstein lists six alternative procedures in his book. Some of these are currently available and others are still undergoing testing. All are non-invasive but are not considered advanced enough to be a replacement for mammograms. These technologies include magnetic resonance imaging (MRI), infrared light scanning, thermography, high definition imaging, and blood and urine tests measuring estrogen levels. Ductal lavage, described as a ‘pap smear for the breast’ is advocated by Dr. Susan Love and is currently undergoing clinical trials (See BCAM Bulletin, Winter 2000). Also under investigation are allergy testing and screening methods to locate gene damage. Like mammography, the results of each of these methods is only as reliable as the person interpreting them. Several experts have suggested that research into alternatives to mammography has been blocked by powerful corporate interests that control the status quo.

All indications lead to the increasing effectiveness of breast examination—particularly Breast Self-Exam (BSE)—as the safest, cheapest and most reliable method for routine screening. The Swedish study indicates that careful and competent breast examinations performed routinely by women themselves, or by doctors or clinicians is still the most effective. Ninety percent of all breast cancers are said to be discovered by women in the shower, during their monthly self-exams, or by their lovers. (Information on how to perform a thorough BSE is available in the BCAM office.)

Why have we not heard about these alternatives?
There is a powerful association between biomedical researchers (public and private), funding agencies and lobbyists who continue to promote early detection as the best prevention. Earlier articles in the BCAM Bulletin have outlined the connections between large chemical companies that produce cancer-causing pesticides and toxins, as well as the drugs used to cure the resulting cancers. Few, if any, of these organizations allot monies to research into determining the fundamental causes of cancer. The mammography industry is a two billion dollar enterprise. General Electric and Siemens are the sole manufacturers of mammography machines; DuPont and Eastman Kodak produce film and accessories. The annual revenue to the industry would increase by another billion-and-a-half dollars if routine screening programs were marketed, especially to women younger than 50. Hence, the age at which routine screening should begin is the subject of continuing controversy, especially in the United States where care is “managed” and “for profit.”

Not unrelated to the difficulties of funding research into alternative procedures is the fact that five past presidents of the American Cancer Society were radiologists. ACS board members routinely move to and from industry, medical/pharmaceutical research, and administration of cancer agencies. Few women are represented. Is it any wonder that less expensive technologies have been ignored?

Two New Studies
Recently, a Swedish team has re-analyzed data from previously published trials and found no reliable evidence that screening decreased breast cancer mortality. They suggest, in fact, that mammography may cause more deaths than it saves.

Similarly, respected Canadian researchers looked at data on annual mammography vis-a-vis annual clinical breast examinations, covering a total of 39,000 women over thirteen years, and found to their surprise that breast cancer mortality was almost identical in both groups. They ask, “Could it be that mammograms are of no value for women of any age?” Both of these studies are highly regarded for their accuracy.

What Can We Do?
As individuals we can be cautious about routine mammogram screenings, choose safer alternatives when possible and avoid all non-essential medical radiation. Monthly breast self exams should become as much a part of our routine as cutting our toenails. We can help to spread the word by talking it up with family and friends. And we should not hesitate to educate our doctors and/or clinicians about the importance of performing thorough (ten-minute) breast exams.

In addition, we need to organize for educational campaigns to encourage women to practice BSE routinely and for the training of doctors and nurses in administering ten minute breast exams. While calling for an end to mammography screening programs may be premature, the need for viable alternatives is clearly indicated. Citizen advocacy is needed to promote safer and less invasive screening methods. Pressure should continue to equalize monies spent on screening programs and research for primary cancer prevention. Demands should be made for more standardized and well-designed research to save unnecessary hardship for thousands of women. All policy-making decisions should be made in the interest of health and safety and not to increase industry profit and power.

The new evidence is unsettling and confusing. Some researchers believe that screening saves lives; for others the question is unresolved. Once again women are left with personal choices. After weighing the evidence each must decide what she wants, what risks she can live with, whom to believe, what and how much to read. Unhappily, there are no easy answers and no consensus about what or who is correct.

Sources

• Epstein, Samuel S., Steinman, D. The Breast Cancer Prevention Program. NY: Macmillan 1997
• Epstein Samuel S., Gross, Lisa. The High Stakes of Cancer Prevention, Tikkun. Vol 15(6) 2000
• Gotzsche PC, Olsen O. Is Screening for breast cancer with Mammography Justifiable? The Lancet, Vol. 355(9198), 2000.
• Hauschildt, Elda. Annual Mammography Offers No Improvement in Breast Cancer Mortality among Middle-aged Women. Journal of the National Cancer Institute (Canada). Vol. 92, November 2000.
• Kasper, Anne S & Ferguson S. J. Breast Cancer: Society Shapes an Epidemic. NY: St Martin’s Press, 2000.
• Miller, Anthony, et al. Canadian National Breast Screening Study - 2: 13-Year Results of a Randomized Trial in Women Aged 50-59 Years. Journal of the National Cancer Institute Vol. 92 (18) September 20, 2000.
• Miller, Fiona A. On Mammography. The Canadian Women’s Health Network Magazine. Spring 2000
• Napoli, MaryAnn. Overdiagnosis and Overtreatment — The Hidden Pitfalls of Cancer Screening. The American Journal of Nursing. Vol. 101 (4) April, 2001
• Questioning Mammography. Breast Cancer Action Newsletter (San Francisco) January/ February 2001

Useful web sites: www.preventcancer.com | www.cancernet.com