Mammograms save lives, but how many?

By Dr. David Lipschitz

Although a small city, Little Rock Arkansas, where I live, has the second-largest Race For The Cure in the country. Thousands of women turned out in support of breast cancer. Many of the women survivors were diagnosed early thanks to annual mammograms. The high cure rate, the commitment of the entire nation to eradicate breast cancer, and meeting and hearing courageous stories of survival is an inspiration and a source of hope for many. Most ascribe early detection by mammograms as the major reason for improved survival in breast cancer.

A significant number of women had tiny tumors that were only detectable by mammograms. But would these tiny tumors have lead to fatality if left alone? A study published in the New England Journal of Medicine compared the rates of breast cancer before and after widespread screening mammograms became available. Instituting screening mammograms increased the diagnosis of very small breast cancers by over 100 percent from 112 cases per 100,000 women in 1976 to 234 per 100,000 in 2008. While tiny tumor diagnoses increased, mammograms did not reduce the rate of diagnosis of late stage disease. Over the 30-year period of study, the number of late stage larger cancers with a higher risk of mortality identified by mammography decreased by only 8 percent from 109 to 94 cases per 100,000 women. If mammography is a successful screening tool, it should detect the earliest cancers, and over time this should be accompanied by at least as great a reduction of the larger more advanced and dangerous tumors. Sadly, this has not occurred.

Dr. A Bleier and Dr. H. G. Welch, the authors of this study, suggest that most of the tiny cancers identified by mammograms were of no clinical significance, would not prove fatal, and that most would spontaneously resolve. Based on these facts, they state that an estimated 1.3 million breast cancers were over diagnosed during the 30-year period of this study, and in 2008 alone, 70,000 women or 31 percent of all new cancers many have not needed treatment.

Everyone agrees that mammograms save lives; the question is how many. Today mammograms as a screening tool for breast cancer are an integral deeply embedded component of the way in which we manage adult women with a goal of early detection of breast cancer. To stop screening mammograms is unthinkable. But we should certainly pay more attention to the age at which mammograms should be done and how frequently. This is critical because the downsides of mammograms do not only include the problem of identifying cancers of no clinical significance, but also the problem of so-called “false positive,” where something suspicious on mammogram leads to needless biopsies and even surgery.Because mammograms have not reduced the rate at which more advanced cancers are diagnosed, they argue therefore that mammograms are having only a small effect on the rate of deaths from breast cancer. The conundrum clinicians face, however, is that to date no one can distinguish a small harmless from a small potentially fatal cancer.

There is still consensus that mammograms should commence at 50 and end at age 75. If a person has no family history of breast cancer, has not used hormone replacement, does not smoke, has had children and has breast fed, a mammogram should be done every 2 -3 years. In Europe, every 3 years is frequently the norm. Mammograms should be done annually in any woman who has a strong family history of breast cancer, particularly if the cancer has occurred at a young age. And based on a careful discussion between doctor and patient, the first mammogram may be recommended at age 40.

The good news is that breast cancer treatments, even for those that have spread to lymph nodes, have a cure rate as high as 85 percent. The key challenge at the moment is the difficult task of distinguishing between tiny cancers identified on mammograms that will never cause a problem and those that, without treatment, will prove fatal. Until such time as this differentiation can be made, we have no choice but to assume that all are potentially fatal and treat accordingly.

Dr. David Lipschitz is the director of The Longevity Center at St. Vincent Infirmary Medical Center. More information is available at: DrDavidHealth.com.