Androgen deprivation therapy (ADT) for node postive prostate cancer

Abstract

5061 Background: The role of ADT for men with node positive prostate cancer following radical prostatectomy (RP) is unclear. One randomized trial has shown a survival advantage for men treated with immediate adjuvant (adj) ADT compared treatment at onset of clinical metastases. However, benefit of immediate therapy is less clear in the PSA era when ADT can initiated at the time of biochemical relapse. Methods: We used linked Surveillance, Epidemiology and End Results-Medicare Data to identify a cohort of men who underwent RP between 1991–1999 and were found to have positive regional lymph nodes. We searched Medicare claims to identify men with claims for ADT (hormonal therapy or orchiectomy) within 3 years of diagnosis. We excluded men who received ADT prior to RP. We classified men as receiving adj ADT if they received treatment within 120 days of RP and compared them to men who had not received adj ADT. We used propensity scores to balance potential confounders of receiving adj ADT (age, tumor characteristics, extent of nodal disease, demographics). We used Cox proportional hazard methods to estimate the impact of adj ADT on overall survival (OS) adjusting for propensity score. We conducted a sensitivity analysis using 90, 150, 180 and 365 days as the time limit for adj ADT. Results: 719 men were identified, of whom 190 received adjuvant ADT within 120 days of RP. There was no statistically significant difference in overall survival between the men who did or did not receive adj ADT (HR 0.96 95% CI 0.70–1.32) The results were similar for men who received ADT within 90 and 150 days. However, when the definition of adj ADT was moved to 180 days (HR 1.08 (0.80–1.47)) and 365 days (HR 1.24 (0.92–1.65)) the men receiving adj ADT had a slightly higher risk of death, suggesting some in the adj ADT groups using these later definitions may have received therapy as salvage therapy for progressive disease. Conclusions: This observational study suggests that in the PSA era when men can be started on ADT at the time of biochemical recurrence, overall survival may not be significantly compromised by deferring immediate ADT in men with positive lymph nodes following RP. Further clinical research is needed to better understand which patients are likely to benefit from immediate ADT, and which men can be spared the long term toxicities. [Table: see text]