CT scans increase the risk of cancer
Two new studies out yesterday in the Archives of Internal Medicine journal address this issue with troubling results. We’ve written before about the new Preventive Health Task Force recommendation changes on routine mammograms for women under 50, and these two new studies are taking on another area where scans are overused. CT scans are enormously popular, and they can be a great diagnostic tool that helps treat serious conditions and avoid exploratory surgery. However, as noted in the commentary accompanying the studies, they carry their own very significant risks:
In other words, 15 000 persons may die as a direct result of CT scans physicians had ordered in 2007 alone. Presumably, as the number of CT scans increase from the 2007 rate, the number of excess cancers also will increase. In light of these data, physicians (and their patients) cannot be complacent about the hazards of radiation or we risk creating a public health time bomb.
The articles in this issue make clear that there is far more radiation from medical CT scans than has been recognized previously, in amounts projected to cause tens of thousands of excess cancers annually. Also, as these scans have become more sensitive, incidental findings lead to additional testing (and often more radiation), biopsies, and anxiety. Although a guiding principle in medicine is to ensure that the benefit of a procedure or therapy outweighs the risk, the explosion of CT scans in the past decade has outpaced evidence of their benefit.
The other interesting finding in these studies is the enormous variation between scans in the amount of radiation dose given, even for the same scan for the same condition in the same hospital. This sort of variation can be fixed by standardizing techniques and therefore lowering drastically the radiation dosages patients receive overall.
Health reform is about containing costs and improving care and studies like these make the case for how we can accomplish both of these goals at the same time. As with the debate over routine mammography though, the overuse of CT scans shows the effort it will take to change people’s minds that more testing and more health care is always better health care. A few years ago full-body annual CT scans were all the rage among well-heeled executives. The research today shows that fad likely caused many cancers among those executives “lucky” enough to have the money for such treatment. Let’s not continue to make the same mistake.