Greatest percent involved core length and the risk of death from prostate cancer in men with highest Gleason score 7 or higher.

Abstract

164 Background: Men with highest Gleason Score (GS) ≥ 7 and a lower GS (Combo GS) have a decreased risk of prostate cancer (PC) specific mortality (PCSM) following radiation therapy (RT) or RT and androgen deprivation therapy (ADT). Whether this risk is modulated based on the greatest percent involved core length (GPC) is unknown and investigated in the current study. Methods: The study cohort consisted of 333 men with GS ≥ 7 PC consecutively treated between 12/1989 and 7/2000 using RT (n = 268; 80%) or RT and 6 months of ADT (n = 65; 20%). Biopsy core and tumor lengths were used to calculate the GPC. Competing risks regression assessed whether increasing GPC was associated with an increased risk of PCSM in men with or without ComboGS adjusting for prognostic factors, age, and treatment. Results: After a median follow-up of 5.36 years (IQR: 3.22-7.61 years) 92 (28%) men died, 28 (30%) from PC. Increasing GPC was significantly associated with an increased risk of PCSM (AHR: 1.02; 95%CI: 1.00, 1.03; p=0.02) (Table). Men with GPC ≥ 50% vs. < 50% had significantly higher estimates of PCSM when ComboGS was present (p< 0.001) vs. absent (p=0.55). Of the 127 men with ComboGS and GPC < 50%, 83% were treated with RT alone and 2 PC deaths were observed; none in men with GS 7 and favorable intermediate-risk PC. Conclusions: Men treated with RT for ComboGS, GPC < 50%, GS 7 and favorable intermediate-risk PC may not require ADT to reduce the risk of PCSM. [Table: see text]