Although prostate-specific antigen (PSA) screening has improved the detection of prostate cancer, allowing for stage migration to less advanced disease, the precise mortality benefit of early detection is unclear. This is in part due to a discrepancy between the two large randomized controlled trials comparing PSA screening to usual care. The European Randomized Study of Screening for Prostate Cancer (ERSPC) found a survival benefit to screening, while the United States Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial did not. Furthermore, the benefit of immediate surgical intervention for screen-detected prostate cancer is unclear, as the results superficially differ between the two large randomized controlled trials comparing prostatectomy to observation. The Prostate Cancer Intervention Versus Observation Trial (PIVOT) found no survival benefit for prostatectomy in PSA screened U.S. men, while the Scandinavian Prostate Cancer Group Study Number Four (SPCG-4) found a survival benefit for prostatectomy in clinically diagnosed prostate cancer. As a result of the controversy surrounding PSA screening and subsequent prostate cancer treatment, guidelines vary widely by organization.