Annual PSA follow-ups not needed in low-risk cases

Patients with surgically treated low-risk prostate cancer may not need annual prostate-specific antigen (PSA) measurements, especially after three years of normal results.

Researchers at the Mayo Clinic in Rochester, Minn., looked at 2,219 patients who underwent radical prostatectomy between 1994 and 2004 for localized prostate cancer. They reported results in the September 2010 Journal of Urology.

They defined low risk as preoperative PSA levels less than 10 ng/mL, pathological stage pT2c or less, Gleason score 6 or less, negative lymph nodes and negative surgical margins. They excluded patients taking neoadjuvant or adjuvant therapy. Biochemical failure was defined as a PSA level above 0.4 ng/mL at any follow-up. PSA levels less than 0.15 ng/mL were defined as undetectable.

One hundred forty-two (6.4%) patients experienced biochemical failure during the study, and the risk decreased with longer PSA-free intervals. Of 2,193 men with undetectable PSA at one year, 84 (3.8%) later had biochemical failure. Of 2,117 patients with undetectable PSA two years postoperatively, 59 (2.8%) experienced biochemical failure. The rate continued to fall at three years (33 of 1,851; 1.8%), four years (22 of 1,567; 1.4%) and five years (19 of 1,351; 1.4%).

Biochemical failure one year after an undetectable PSA level is uncommon, especially after a PSA-free period of three years, researchers noted. Prostate-specific antigen measurements every two years should capture the majority of low-risk patients who experience progression, researchers suggested.

"A benefit to an upfront, aggressive surgical approach to localized prostate cancer should be that postoperative surveillance is less necessary and less intensive," the authors wrote. "It only makes sense that men undergoing [radical prostatectomy] for pathologically proven low risk disease should be screened less often."