It’s just hard to wrap your head around. Cancer screening tests — mammograms, PSA levels, colonoscopies — check for early tumors. Catching cancer earlier is better than later. And yet some research suggests that screening — at least for breast and prostate cancer — may be of dubious worth, because it catches many cancers that would never have posed a danger.
The latest salvo on this controversial topic came last week from Dartmouth’s Dr. H. Gilbert Welch, a leading voice on the problem of overdiagnosis, in a New England Journal of Medicine study and an op-ed in The New York Times. He sums up his findings on three decades of mammogram screening in the Times:
…More than a million women who were told they had early stage cancer — most of whom underwent surgery, chemotherapy or radiation — for a “cancer” that was never going to make them sick. Although it’s impossible to know which women these are, that’s some pretty serious harm.
But even more damaging is what these data suggest about the benefit of screening. If it does not advance the time of diagnosis of late-stage cancer, it won’t reduce mortality. In fact, we found no change in the number of women with life-threatening metastatic breast cancer.
Have lingering questions? Tune in to Radio Boston today a little after 3 p.m. for a discussion of the issue that will include a chance to call in. And it may help to view the video above, in which Dr. Welch explains his findings.