SALVAGE RADIATION THERAPY FOR PROSTATE SPECIFIC ANTIGEN PROGRESSION FOLLOWING RADICAL PROSTATECTOMY: 10-YEAR OUTCOME ESTIMATES

Abstract

We evaluated men treated with salvage radiation therapy for increasing serum prostate specific antigen (PSA) following radical retropubic prostatectomy (RRP). We retrospectively reviewed the records of 3,478 consecutive men who underwent radical retropubic prostatectomy (RRP) between 1983 and 2003, as performed by a single surgeon. A total of 307 men received salvage radiation therapy for persistently increased or increasing PSA after RRP. We compared perioperative and peri-radiotherapy clinicopathological parameters in men who achieved an undetectable PSA level after radiation therapy (responders) vs those who did not (nonresponders). We then evaluated the durability of the PSA response. Median time from RRP to PSA progression was 23 months (range 1 to 129). Median followup from RRP was 104 months (range 7 to 225). Median followup from salvage radiotherapy was 56 months (range 0 to 188). Of 223 men with sufficient followup information 162 (73%) subsequently had undetectable PSA (less than 0.3 ng/ml) in response to salvage radiation therapy. There was no significant difference between responders and nonresponders in the distribution of clinical and pathological tumor stages, age at RRP, surgical margin status, and the interval between RRP and salvage radiation therapy. A Gleason score of 8 to 10 was more prevalent in nonresponders than responders (28% vs 13%). Median PSA at salvage radiation therapy was 1.2 ng/ml in nonresponders vs 0.7 ng/ml in responders. Actuarial 5 and 10-year progression-free (PSA less than 0.3 ng/ml) survival probabilities in all 223 men following salvage radiation therapy were 40% (95% CI 32 to 48) and 25% (95% CI 15 to 36), respectively. Actuarial 5 and 10-year biochemical progression-free survival estimates following salvage radiation therapy in responders only were 55% (95% CI 45 to 64) and 35% (95% CI 21 to 49), respectively. Only seminal vesicle invasion was significantly associated with progression-free survival following radiation therapy on multivariate analysis. An undetectable PSA level following salvage radiation therapy is more frequently achieved in men with lower pre-radiation serum PSA and those without seminal vesicle or lymph node involvement. Overall approximately a fourth of men with PSA evidence of cancer progression following RRP had a durable response 10 years after the initiation of salvage radiation therapy in the protocols used in this patient cohort.