Prostate-specific antigen (PSA) measurements at 2 years should capture the majority of low-risk cases that progress after treatment with radical prostatectomy, suggests a new study in the September issue of the Journal of Urology.
Researchers at the Mayo Medical School, Rochester, Minnesota, identified 2219 patients who were treated with radical prostatectomy between 1994 and 2004 for low-risk localized prostate cancer. As per current protocol, after surgery these patients underwent PSA screening every 3 months in the first year, every 6 months in the second year, and then yearly thereafter. Low-risk was defined as PSA <10 ng/mL, pathological stage pT2c or less, Gleason score ≤6, negative lymph nodes, and negative surgical margins.
The researchers found that 142 (6.4%) patients experienced biochemical failure during the course of the study. Analysis showed that the longer the PSA-free interval, the lower the risk of biochemical failure. The study provided this example: patients at 1, 3, and 5 years had cumulative biochemical failure rates of 1.8%, 4.2%, and 6.3%. Patients with undetectable PSA at 5 years biochemical failure rates at 10 years were essentially zero.
Because these results show that the risk of biochemical failure is inversely proportional to the duration of PSA-free interval after radical prostatectomy in low-risk patients, the authors suggest that the practice of yearly PSA surveillance for the patient’s life can be modified to testing every 2 years for these patients.