Does adjuvant treatment affect survival in patients with positive lymph nodes at radical prostatectomy?

Abstract

157 Background: Men who are found to have positive LN at the time of RP are at risk for worse prognosis and outcomes. Our purpose is to determine whether RT after RP has a greater survival benefit than ADT alone or surgery alone in these men. Methods: This study cohort consisted of men who had RP at the University of California, San Francisco. Men with positive pelvic LN were stratified by type of adjuvant therapy: ADT, RT with or without ADT, or RP only. T-test and chi-square were used to compare clinical and pathologic characteristics. Biochemical recurrence-free, metastatic recurrence-free, and disease-specific survival were assessed with the Kaplan-Meier method, log-rank test, and Cox proportional hazards regression. Biochemical recurrence was defined as two consecutive prostate-specific antigen values >=0.2ng/mL. Results: Of the 1,600 men had pelvic LN dissection at time of RP, 105 had positive LN. Mean age was 61 (SD 7). Median number of LN dissected was 14 (IQR 10-21) for pN1 patients versus nine (5 to 15) for pN0, p<0.01. Median percentage of positive LN was 11% (IQR 7-17). Men with positive LN had higher clinical risk and worse pathologic grade, positive margin rates, and T-stage compared to men without positive LN, all p<0.01. Recurrence-free survival was 55% for pN1 versus 81% for pN1 at 5 years, log-rank p<0.01. Following positive LN dissection at RP, 29 men received ADT monotherapy, 43 men received RT (+/- ADT), and 33 had not yet undergone treatment after RP during a median follow up of 28 months (IQR 6 to 70). Rates of seminal vesicle invasion by treatment group were 52% for ADT, 65% for RT (+/- ADT), and 35% for RP only, p=0.03. Men who underwent ADT alone, RT (+/- ADT), and RP only had few outcome events to date and similar rates of MFS (97% versus 93% versus 92%, p=0.76) and DSS (96% vs. 100% vs. 100%, p=0.32) at 3 years. Cox regression adjusted for surgical CAPRA score also showed that MFS and DSS did not differ between ADT alone, RT (+/- ADT), and RP only groups. Conclusions: Men with positive LN at the time of RP have aggressive clinical and pathologic features. Nevertheless, metastatic recurrence-free and prostate cancer-specific survival rates 3 years after surgery remain good. Although no additional survival benefit to post-RP RT was seen in this cohort of men with limited follow up, further follow up is ongoing.