The Wall Street Journal’s health blog asks “How much are CT scans increasing cancer risk?” A recent article in the New England Journal of Medicine claimed that the scans could be causing 1.5 to 2 percent of all cancers. The WSJ blog found other medical experts who questioned the study.

Arl Van Moore, chairman the American College of Radiology’s board, told the WSJ that “there are scans performed that may well be unnecessary,” But he called the authors’ conclusions about the possible 2% rate of future cancer diagnoses “a reach.” And he told the AP “there are some serious concerns about the methodology used” in the paper.

It is tough to estimate the risk of developing cancer from radiation risk. As the authors (two Ph.D.s from Columbia’s Center for Radiological Research) point out, most such estimates are based on studies of survivors of the atomic bombs dropped on Japan in 1945.

Still, what if the “62 million CT scans every year” in America were the cause of only .1 percent of all cancers in the country? That would still be a significant number.

Kevin MD has blogged twice on the subject this week (here and here).  He thinks defensive medicine has a lot to do with the high number of CT scans.  The articles he quotes don’t explicitly mention defensive medicine as a reason, but one does speak of catching possible problems early and keeping down expenses.  I have a hard time believing that there aren’t medmal concerns lurking in the background.