2287: The Impact of Primary Gleason Pattern on Survival Following Brachytherapy for Gleason Score 7 Prostate Cancer

Abstract

A recent radical prostatectomy series reported lower rates of biochemical control and cause-specific survival in Gleason score 7 patients with primary Gleason pattern 4. In this study, we evaluated the impact of Gleason 4 +3 versus 3+4 on cause-specific, biochemical progression-free and overall survival in patients managed with permanent prostate brachytherapy. From April 1995 to April 2003, 507 prostate cancer patients underwent permanent prostate brachytherapy for clinical stage T1b-T3a (2002 AJCC) prostate cancer with Gleason 3+4 (n=290) or Gleason 4+3 (n=270) cytology. All patients underwent brachytherapy more than three years prior to analysis. The mean and median follow up was 5.9 and 5.6 years, respectively (range 3–11 years). Of the evaluated cohort, 396 (78.1%) received supplemental XRT and 167 (33%) received androgen deprivation therapy. No statistical differences were discerned between the use of XRT, however, Gleason 4+3 patients were more likely (37.3% vs 29.7%, p=0.004) to receive ADT. Multiple clinical, treatment and dosimetric parameters were evaluated as predictors of cause-specific, biochemical progression-free and overall survival. The 10 year cause-specific, biochemical progression-free and overall survival for the entire cohort was 97.0%, 95.7% and 79.2% respectively. Primary Gleason 3+4 versus 4+3 did not predict for cause-specific (95.8% vs 98.0%, p=0.794), biochemical progression-free (97.2% vs 93.5% p=0.072) or overall survival (80.2% vs 77.7%, p=0.857). The Cox linear regression analysis demonstrated no significant predictors for cause-specific survival while percent positive biopsies, prostate volume and risk group predicted for biochemical progression-free survival. Patient age, tobacco use, and diabetes were the strongest predictors of overall survival. To date, 49 patients have died (22 with Gleason 4+3 and 27 with Gleason 3+4). Of the deaths, 37 (76%) were due to cardiovascular events (24) or second malignancies (13). To date, 4 patients (2 in each cohort) have died of metastatic prostate cancer. Following brachytherapy, the primary Gleason pattern did not impact cause-specific, biochemical progression-free or overall survival in patients with Gleason score 7 prostate cancer. Cardiovascular disease and second malignancies were responsible for 9 times more deaths than prostate cancer.