ORLANDO — Metastasis occurs after surgical removal of low-grade prostate cancer in some men, suggesting that close follow-up is warranted.
Although there is an overall 30% recurrence rate a decade after prostatectomy, a man with a Gleason score of 6 or less generally has a more favorable prognosis, Dr. Marc Birkhahn said.
He and his associates assessed 3,235 consecutive patients who had a radical prostatectomy and bilateral lymphadenectomy for prostate cancer between 1972 and 2005 in the University of Southern California/Norris Comprehensive Cancer Center database. From this group, they identified 1,383 men with a Gleason score of 6 or less.
Of the 1,383 men, 70% had a Gleason score of 6, 24% had a score of 5, 4% had a score of 4, and 2% had a score 3 or 2. Only 2% had node-positive disease. The cancer stages were pT2 (83%), pT3 (16%), and pT4 (1%). This is noteworthy because “tumor stage and Gleason score are the most important predictors of recurrence,” Dr. Birkhahn said at the annual meeting of the American Urologic Association.
Biochemical recurrence occurred in 147 patients a mean of 4 years after surgery. Clinical recurrence (metastasis) occurred in 45 men a mean of 8 years postoperatively. Metastasis-free survival in the entire cohort of 3,235 men was 96% after 10 years and 94% after 15 years.
Among all patients in the total database with metastasis or recurrence after radical prostatectomy, “26% of PSA recurrences and 20% of clinical recurrences occurred in men with a Gleason score of 6 or less,” said Dr. Birkhahn of the University of Southern California, Los Angeles. “Tumors with a Gleason score of 6 or lower are low risk but not no risk.”