Dr. Otis Brawley, Chief Medical Officer of the American Cancer Society, voiced strong support for annual mammography for women beginning at age 40 in an Op-Ed piece published November 20, 2009, in newspapers nationwide. This position is in sharp contrast to his statement about mammography made in the New York Times on Wednesday, October 21, 2009. On that day he told women "We don't want people to panic, but I'm admitting that American medicine has overpromised when it comes to screening. The advantages to screening have been exaggerated." Dr. Brawley has known about the questionable benefits of screening for more than a decade. Regarding mammography, his words in the August 2000 issue of Hematology/Oncology Clinics of North America were, "There has been considerable debate about the benefit:harm ratio of mammography screening for women below the age of 50 years, and about what proportion of the observed benefit arises from screening that occurs after these women have entered their 50s." The burden of proof of "the benefits outweighing the harms" rests with those making the recommendations--the American Cancer Society and its Chief Medical Officer in this case. Dr. Brawley has voiced doubt about the benefits of mammography, and now appears conflicted by communicating two opposing stands in less than a month. The American Cancer Society, on the other hand, has remained steadfast in a position that enhances the profits of breast cancer-related businesses, regardless of the effects on women.
Adequate scientific evidence to stop mass screening programs, such as mammography, has been readily available for more than three decades. In 1976 Pietro M. Gullino presented his findings on the natural history of cancer, showing "early detection" is really "late detection," at the Conference on Breast Cancer: A Report to the Profession, sponsored by the White House, the National Cancer Institute, and the American Cancer Society. He explained: "If the time required for a tumor to double its diameter during a known period of time is taken as a measure of growth rate, one can calculate by extrapolation that two-thirds of the duration of a breast cancer remains undetectable by the patient or physician. Long before a breast carcinoma can be detected by present technology, metastatic spread may occur and does in most cases." This report was subsequently published in the journal representing the American Cancer Society (Cancer 1977 Jun;39(6 Suppl):2697-703).
This largely invisible natural history of breast cancer was further explained to doctors and scientists in 1997 in an article published in the Journal of Surgical Oncology titled, "On the growth rates of human malignant tumors: implications for medical decision-making." The authors, Friberg and Mattson concluded, "Most tumors are several years old when detectable by present-day diagnostic methods. This makes the term 'early detection' questionable." (J Surg Oncol. 1997 Aug;65(4):284-97).
For a cancer in the breast to grow from one cell to one centimeter in diameter--a size that can be detected by breast self-examination or mammography--on average takes ten years. Unfortunately, when the cancer is still so tiny that it cannot be detected, it nevertheless has already spread (metastasized in medical terminology) to other parts of the body in virtually every case of true cancer (as opposed to the latent forms of cancer). It is the cancer cells that have spread to, say, the liver, lungs, bones, and brain, that kill the patient, and not the cancer cells confined to the breast.
Just as tragic is the devastation to the lives of millions of women with indolent cancers (the latent forms) that would have never appeared in their lifetime if no one had been busy looking for them with screening programs. Once found, these nonthreatening lesions are aggressively treated with life-changing surgeries, radiation treatments, and/or chemotherapies.
The American Cancer Society and its representatives need to provide an unambiguous message to women that screening mammography is a blunt technology, and that even after four decades of use the evidence has not shown that the benefits outweigh the harms. Understanding the natural history of this disease could lead to no other conclusion.
John McDougall, MD
www.drmcdougall.com