JONATHAN SALTZMAN’S article about prostate biopsy errors (“Mistakes that matter,’’ Metro, Aug. 2) helps explain some results in the March 2009 article “Mortality Results from a Randomized Prostate-Cancer Screening Trial’’ in the New England Journal of Medicine. In that trial, 76,693 men in 10 US study centers were randomly assigned to two groups: the first, with 38,343 men, had annual screening for prostate cancer, and the second, with 38,350 men, were not offered screening. After 10 years, there were 92 prostate cancer deaths in the screened group, but only 82 prostate cancer deaths in the control group. In addition, after 10 years, 3,452 screened men had been diagnosed as having prostate cancer, whereas only 2,974 men in the control group had been diagnosed as having prostate cancer.
Many men might have been led to believe that screening had saved them from dying from prostate cancer, even though the screened men were more likely to have died from prostate cancer.
Some newspapers might just report the study’s conclusion that “the rate of death from prostate cancer . . . did not differ significantly between the two study groups.’’ Nevertheless, it seems to me that this study shows that screening is more likely to make one think one has cancer (whether due to mix-ups such as those described in Saltzman’s Globe article, or, more likely, due to a tendency of screening tests to diagnose a cancer that would never have caused a problem if it hadn’t been diagnosed), and that screening makes it somewhat more likely that you’ll die from cancer.