Re: Is a screening interval of every 4 years for prostate cancer acceptable?

EDITORIALS In this issue of the Journal, Roobol et al. (1) report an analysis of two different screening intervals in the large European Randomized study of Screening for Prostate Cancer (ERSPC) to defend a screening interval of every 4 years. In contrast to the yearly screening for prostate cancer in the United States, most centers in the ERSPC trial chose to screen men every 4 years. Critics of the 4-year screening interval have voiced concerns that clinically significant cancers could be missed by such an extended interval. The authors attempted to soothe these concerns by comparing two screening intervals (2-year versus 4-year) within the ERSPC trial. Although they found that the incidence of interval cancers did not differ by screening interval, I am not convinced that their analysis has allayed these fears. Why screen for prostate cancer? In 1989, prostate cancer became the most common cancer diagnosed in American men and the second leading cause of death (2). The majority of prostate cancers were either locally advanced or metastatic when diagnosed. The impact of prostate cancer on the male population is large — 17% of men will develop it and approximately 3% will die from the disease (3). Three possible approaches exist to deal with this common neoplasm. The fi rst is to develop a cure for advanced prostate cancer, but this has not yet been achieved. The second is to try to prevent the disease. An effective preventive agent was recently identifi ed: fi nasteride, which reduced the 7-year period prevalence of prostate cancer by 25% (4). However, because of the initial concern that the drug could induce high-grade tumors in treated men, this approach to prevention was not embraced. Recent analysis would suggest that this high-grade cancer phenomenon may have been an artifact (5). A third approach is to fi nd the disease early, treat it, and cure it; this approach is known as screening or early detection. Screening for prostate cancer is controversial — some medical organizations support it, and others are skeptical. These controversies led to the development of a large randomized clinical trial in the United States to determine the value, if any, of early detection of prostate cancer: the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) trial. This very important ran-domized trial began in 1992 (6). In this trial, a yearly screening interval for prostate cancer was chosen, and screening consisted of a serum …