> Comments on Mammography Leading to Over-Diagnosis and Over-Treatment (Dr. Eric Winer, October 2009)
Recent media attention has shed light on the issue of mammography leading to over-diagnosis and over-treatment. According to a study published in the British Medical Journal, researchers from Copenhagen analyzed breast cancer trends in the years before and after the initiation of government-run mammography screening programs in Australia, the United Kingdom, Canada, Sweden and Norway. The data covered a period of at least seven years before and after screening. The results suggested that one in three women who were identified as having breast cancer might not have needed treatment. Unfortunately, we do not know which women would have done well without treatment, and which would develop a life-threatening (and in some cases, life-ending) disease if the cancer were not treated.
The problem with mammography is magnified when we also consider non-invasive breast cancer, or ductal carcinoma in situ (DCIS). In this setting, the disease is not life- threatening when diagnosed, and an even greater number of these women might do well without treatment. Once again, however, we don't know which women might subsequently develop an invasive cancer if the DCIS were left untreated.
False positives and overdiagnosis are a problem with almost any screening test. The same concerns have been raised with screening for other cancer and other health conditions. In the perfect world, a screening test would accurately identify all persons who, if left untreated, would develop serious consequences. The ideal test has no false positives and no cases of overdiagnosis. Unfortunately, we are not aware of any test that meets this stringent set of requirements.
We need to strive to eliminate overdiagnosis, and those studies, admittedly, will be hard to conduct. At the same time, with the growth of targeted therapy and personalized medicine, we are rapidly on the way to better understanding which treatments are right for each person. We must continue to work to reduce mortality and improve the quality of life for all women with breast cancer and those at risk of developing breast cancer.
Any health-related decision is a personal one that involves balancing risks and benefits. At Susan G. Komen for the Cure®, we encourage all women to follow the recommended breast cancer screening guidelines based upon age, personal risk and physician recommendation. These include getting a mammogram every year starting at age 40 for women at average risk and getting specific screening recommendations from physicians for women at higher risk. We also encourage women to discuss these guidelines with their health care providers, and if they are concerned about overdiagnosis or the value of a screening test, to raise these concerns. Ultimately, each woman needs to make medical decisions that are in keeping with her values and, ideally, maximize her chance of having a long and healthy life.