Dr. Lee discusses how mammograms are not evidence-based medicine and how dangerous they can be for women who have undected breast cancer.
ARE MAMMOGRAMS WORTH IT?
Does squashing and irradiating the breasts really lead to fewer deaths from breast cancer?
I like to heat my family room with a wood stove in the winter, and in the morning often start the fire by simply placing some wood on top of old coals that are still alive under the ashes. First the wood smokes, and then a small flame usually pops up somewhere and flickers for awhile. Not long afterwards, the whole pile of logs bursts into flame almost simultaneously and the house begins to warm up.
In medicine, a concept that is ready to be born tends to spring to life in much the same way: new ideas are laid upon the ashes of practices that no longer work, and the flame of awareness flickers to life in the minds of doctors and patients. Word spreads and eventually there’s enough “heat” generated to enliven and enlighten the consciousness of medical practice, and the new concept takes hold.
Routine Mammograms are not an Evidence-Based Practice
Mammography is a good example of this principle. In spite of little evidence of their effectiveness, mammograms became a routine exam in conventional medicine back in the early 1970s. Just the concept of being able to view lumps in the breast with a machine and thus detect breast cancer earlier was exciting enough to carry the idea for a couple of decades. This in spite of the fact that it involves forcefully squashing the breasts and irradiating them – both potential risk factors for breast cancer. Then there was the economic side of mammograms: if every woman over the age of 35, or 40 or 50 (it kept changing) were to get a mammogram every year or two, that meant big bucks for hospitals and clinics.
After a decade or so, countries with socialized medicine where the government was spending the big bucks for routine mammograms, began to question their value and look more closely at the statistics in their huge national databases. What they discovered was that mammograms don’t save lives. Yes, a good technician and skilled radiologist can often detect a lump in the breast a year or so earlier than a woman can checking her own breasts, but that year wasn’t making much difference in whether or not the woman died of breast cancer.
The flicker of a new concept that perhaps mammograms shouldn’t be a routine exam, which was near-heresy just a few years ago, began to take a hold, and just in the past few months has burst into flame. Women are staying away from mammograms by the thousands.
While I wholeheartedly support staying away from routine mammograms, you need to be very conscientious about checking your breasts for lumps at least once a month. Women who get routine annual mammograms have a tendency to turn over the responsibility of breast lump detection to the radiologist. That was never a good idea. It’s your body, they’re your breasts, and once you become familiar with how they look and feel, you’ll be able to detect something unusual. This does not mean that it’s your “fault” if you don’t detect a breast cancer. Just do the best you can. If you do detect a lump in your breast, by all means go and get a mammogram.
The death of the routine mammogram brings to the forefront more than ever the necessity to prevent breast cancer in the first place. This is where the real work needs to be done: the environment needs to be cleaned up, HRT needs to be properly prescribed, and women need to be educated about what causes breast cancer.
It’s Time to Question the Value of Mammography
New studies have cast doubt on whether these unpleasant procedures save lives. Mammography is big business these days. Countless advertisements and physicians are telling women to have mammograms. But the value of this procedure is far from clear. We all know mammograms have a high risk of false positive and false negative findings. The test procedure is unpleasant and radiation is potentially harmful.
Mammography is claimed to lower the risk of dying from breast cancer. Proponents argue that mammography can detect breast tumors a year or so earlier than simple palpation. This “early” detection, so the argument goes, leads to earlier treatment and a lower risk of breast cancer mortality. Statistics, it is claimed, have validated this argument.
Many statisticians, however, disagree. Statistics are not immune from biases, which include mechanical factors, (different measuring instruments in different subjects), study methodology, conscious or unconscious assumptions, age of subjects, socioeconomic factors, faulty randomization of subjects and controls, duration of observation, and other confounding factors.
Lead Time Bias Casts Doubts
More than 15 years ago, Dr. John C. Bailar III observed that counting survival time after treatment creates a bias in most mammography studies because mammography detects breast tumors a year before they would have been found by palpation. He pointed out that subjects with breast tumors found by palpation have lived at least a year prior to the time when they would have been found by mammography. When this year is added to the survival time of the "control" women (who did not use mammography), their survival results match that of "subject" women whose tumors were found by mammography.
This means that the apparent difference in survival after treatment was not due to earlier treatment, as a result of mammography, but due merely to starting the counting of survival time one year earlier in the mammography subjects. When this factor is included in the statistical analysis, the so-called “benefit” of mammography and earlier treatment disappears. Dr. Bailar, now Professor of Epidemiology and Biostatistics at McGill University and Senior Scientist in the Office of Disease Prevention and Health Promotion, U.S. Department of Health and Human Services, calls this the “lead time” bias.
This should not be surprising. For a breast cancer cell to become large enough for detection by palpation, the cancer has to have been growing for about 10 years. If found one year earlier by mammography, the cancer has been growing for about nine years, which is plenty of time to spawn metastases if the cancer is prone to do that. The one-year difference between palpation and mammography detection is ultimately of little importance.
Two New Studies Raise Big Questions
Does mammography truly save lives? If you read the numerous ads for it you might think the case is closed—of course it does. If you read the studies themselves, the answer is not so clear. For example, a 1999 epidemiological study found no decrease in breast cancer mortality in Sweden, where mammography screening has been recommended since 1985. (Sjonell G, Stahle L. Halsokontroller med mammografi minskar inte dodligheten i brostcancer. Lakartidningen 1999; 96: 904-913.)
As a result, two Swedish scientists reviewed all published mammography trials to evaluate their methodological quality. Their purpose was to ascertain whether or not mammography truly saved lives. (Getzsche PC, Olsen O. Is screening for breast cancer with mammography justifiable? Lancet 2000; 355: 129-134.) Their findings are worth a close look.
In their meta-analysis of eight identifiable mammography trials, the authors found six of them seriously flawed by baseline imbalances and/or inconsistencies of randomization. The flaws were sufficient to nullify the studies’ claims of a benefit from mammography. The two adequately randomized trials found no effect of mammography screening on breast cancer mortality (death).
The meta-analysis conclusion is clear. Since there is no reliable evidence that mammography screening decreases breast cancer mortality, mammography screening for breast cancer is unjustified. This means that physicians should not order mammography screening, and insurance companies and HMOs should not pay for such tests.
This conclusion is not as dismal as it might first appear. Mammography screening should be dropped because it doesn’t work to save lives. We get by that hurdle by turning our attention to more promising research. First we must change our thinking to separate cause from effects. The cancer tumor is not the disease; the tumor is the result of an underlying metabolic imbalance. Removing the tumor is not treating the cause; it is merely removing an effect of the disease. If the underlying imbalance is not corrected, the disease has not been treated.
When conventional medicine turns its attention to hormonal imbalance, nutrition and the effects of xenoestrogens, progress in the prevention and treatment of breast cancer is far more likely than it is if we continue on with our present fixation on mammograms, surgery, chemotherapy and radiation.
For detailed information about hormone balance and breast cancer, please read What Your Doctor May Not Tell You about Breast Cancer, by John R. Lee, M.D., Dr. David Zava, and Virginia Hopkins.
This article is a compilation of articles originially published in the John R. Lee, M.D. Medical Letter. Although the Medical Letter is no longer published, you will find many articles from it published on this website.