In recent years there has been an increase in the incidence of women suffering from breast cancer. It is one of the largest causes of death among women. This has caused women to undertake regular check-ups in order to detect cancer early in its starting stage.
Women over 40 are advised to take yearly mammograms in order to be able to detect breast cancer. However, a new study published in The New England Journal of Medicine suggests that mammograms may not be able to save lives as presumed by doctors. The study further states that the tests may in fact be harmful, causing nearly 1.3 million women to be treated in the US over the last 30 years that would not have caused clinical symptoms.
Researchers believe that it is for good that the potential harm was identified early. Although mammograms are extremely useful in saving lives, its usage should be limited and not so often. The guidelines chalked out by the US Preventive Services Task Force suggest the use of mammograms after the age of 50 and should be done every other year until 75 years of age.
On the other hand, other organizations, including the coveted American Cancer Society as well as the American College of Obstetricians and Gynecologists suggest annual mammograms from the age of 40 years. The new study has not been rubbished completely by the American Cancer Society and is willing to delve deeper into it.
Overdiagnosis of Breast Cancer
The study was conducted by looking at breast cancer detection trends from 1976 to 2008 in the US. The rates of breast cancer diagnoses were compared by researchers, before as well as after mammogram came into wide use for screening purposes.
The results were adjusted by researchers in order to remove extra cancers which were believed to be related to the large-scale use of hormone replacement therapy (HRT). Although mammograms did help in finding early-stage breast cancer, these findings did not help to prevent late-stage disease. Late-stage breast cancer is much more life-threatening and the number of such late-stage breast cancer dropped only slightly, from 102 to 94 cases per 1000 women.
Thus this means that most of the early breast cancers detected by mammograms, nearly half of them, are harmless and are merely ‘overdiagnosed’ i.e. diagnosing something which is non- relevant. It means that whatever is found would not have had any effect on the person’s life and might have not known about it at all.
The actual problem lies in the fact that doctors are unable to distinguish early-stage harmless cancers from life-threatening ones. Thus, once the cancer is detected, patients are advised to follow treatment procedures such as surgery, chemotherapy, and radiation. If there was a way to identify patients during the diagnosis regarding which cancers are actually problematic, it would have saved many women from unnecessary treatment procedures.
The study was not only limited to the over-diagnosis aspect, it also tried to study whether mammograms helped to save lives. During the course of the study, the death rate from breast cancer of women 40 years and older dropped by 28% however death rates declined, even more, 42% for under 40 women. Thus the decline is attributed to better treatments than early detection.
The study is not the first one to show the harmful effects of overdiagnosis caused due to mammograms, there have been other 10 studies carried out in Europe as well as Australia which estimate that 10% to 47% of cancers detected in these regions are treated unnecessarily.
Although the studies are an eye-opener, they are not definite numbers and are estimations that are subject to errors. Also, the studies cannot be applied to everyone in general. For example, those with a family history of this condition cannot be included in this generalization as in their case early detection is detrimental.
To summarize, the new study is extremely important in learning the effects of excessive mammograms, but also needs more literature on this subject.