Controversy persists about the benefit of prostate cancer screening. Adding to this debate are results from a case-control study from 10 Veterans Affairs medical centers in New England. Researchers identified 501 cases (median age, 72) in whom prostate cancer was diagnosed from 1991 through 1996 and who died before 1999. Controls were 501 randomly selected men (with or without prostate cancer; matched for age and medical center) who were alive when their corresponding case patient died. Investigators reviewed medical records to determine whether cases and controls had received prostate-specific antigen testing (with or without digital rectal exams) between January 1, 1991, and the date of the case’s cancer diagnosis.
Cases and controls had similar rates of prostate cancer screening prior to the case diagnosis (if screening had been effective, one would have expected a lower rate of screening among cases than among controls). At diagnosis, 25% of cancers were nonlocalized, 51% were moderately differentiated, and 23% were poorly differentiated. Treatment included surgery or radiation for 42% of cases, hormonal treatment for 35%, and watchful waiting for 21%.
Screening for prostate cancer failed to show a mortality benefit in this case-control study. However, the study design might be responsible for these findings: Because death was a selection criterion for cases, patients with more aggressive malignancies probably were selected. For more definitive answers, we will have to wait until 2009, when results are expected from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and the European Randomized Study of Screening for Prostate Cancer.
Reference:
1. Concato J et al. The effectiveness of screening for prostate cancer: A nested case-control study. Arch Intern Med 2006 Jan 9; 166:38-43.
2. Barry MJ. The PSA conundrum. Arch Intern Med 2006 Jan 9; 166:7-8.