by Chris Bodenner
This post by Dr. Lundberg - arguing for the curtailing of mammograms for women under 50 as one way to save billions of dollars - irked some for its alleged concern for cost over care. Lundberg wrote that such testing "seems to lead to at least as much harm as good," but failed to elaborate. A reader writes:
I'm a medical imaging physicist. Some women under 50 will have their breast cancer detected by mammograms. But some women will have breast cancer induced by the radiation used to make the mammograms. Mammography (and any imaging procedure involving ionizing radiation) is only advisable if the chance of saving a life exceeds the chance of causing cancer.
Mammography is unique because its a screening modality, one of a handful of routine uses of ionizing radiation on healthy patients. The older you are, the more sense it makes to have a mammogram for two reasons: the more likely you are to have breast cancer and the more likely you'll die from other causes before the radiation damage can cause a future cancer. For women in their 20s, the medical risks of mammograms outweigh their benefits. For women in their 70s, the benefits outweigh the risks. For women in their 40's, the risks and benefits are roughly balanced. Neither the risks nor the benefits are particularly precisely known, so its difficult to say at what age the risks outweigh the benefits. Its possible that for women in their 50s, the net benefits of screening mammography are small (only a few women in this group will be saved by mammography, perhaps not many more than the few who would develop fatal cancer due to their mammography) and raising the age might save society some money.
Similar arguments can be applied to other uses of radiation as a screening tool. There has been a push to have Cardiac CT screening scans of healthy patients, especially by cardiologists who own CT scans and profit from each scan. Not only are these scans expensive, but they also pose a (small) risk to the patients who may subsequently develop cancer as a result of their scans. These small risks can outweigh the small benefits of the scans to healthy patients.