Could Mammograms be the Cause of Some Breast Cancers?
In the on-going debate over when to start getting mammograms and how often to have them the assumption by many of those supporting an "early and often" policy has been that false positives lead to little more than worry and maybe a needle biopsy. Now The New York Times is reporting on a study that appears to demonstrate that young women already at heightened risk of breast cancer double that risk if they start getting mammograms early.
Five prior studies of women carrying a mutation that is thought to put them at increased risk of breast cancer were examined to determine whether low dose radiation exposures from mammograms further increased that risk. The results, which were statistically significant at a 95% confidence interval, showed that women carrying the breast cancer gene who started mammography early in life or who had five or more mammograms were more than twice as likely to develop breast cancer as women with the breast cancer gene who started getting mammogramps later and had fewer of them.
The working hypothesis is that mammography actually causes many cases of breast cancer in susceptible women. An alternate explanation, I suppose, is that about half of all breast cancers detected by mammography either aren't cancerous or were never going to develop into a malignancy.
Hopefully doctors are finally beginning to discuss the large and unsettling uncertainties associated with the diagnosis, treatment and causal attribution of poorly understood diseases like cancer.
