Adjuvant radiation with androgen-deprivation therapy for men with lymph node metastases after radical prostatectomy: identifying men who benefit

Objectives: To perform a comparative analysis of three current management strategies for patients with lymph node metastases (LNM; pN1) following radical prostatectomy (RP): observation, androgen-deprivation therapy (ADT), and external beam radiation therapy (EBRT) + ADT.

Patients and methods: Patients with LNM after RP were identified using the National Cancer Database (2004-2013). Exclusion criteria included any use of radiation therapy or ADT before RP, clinical M1 disease, or incomplete follow-up data. Patients were categorised according to postoperative management strategy. The primary outcome was overall survival (OS). Kaplan-Meier curves and adjusted multivariable Cox proportional hazards models were employed. Sub-analyses further evaluated patient risk stratification and time to receipt of adjuvant therapy.

Results: A total of 8 074 patients met the inclusion criteria. Postoperatively, 4 489 (55.6%) received observation, 2 065 (25.6%) ADT, and 1 520 (18.8%) ADT + EBRT. The mean (median; interquartile range) follow-up was 52.3 (48.0; 28.5-73.5) months. Patients receiving ADT or ADT + EBRT had higher pathological Gleason scores, T-stage, positive surgical margin rates, and nodal burden. Adjusted multivariable Cox models showed improved OS for ADT + EBRT vs observation (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.64-0.94; P = 0.008) and vs ADT (HR 0.76, 95% CI: 0.63-0.93; P = 0.007). There was no difference in OS for ADT vs observation (HR 1.01, 95% CI: 0.87-1.18; P = 0.88). Findings were similar when restricting adjuvant cohorts for timing of adjuvant therapy. There was no difference in OS between groups for up to 2 549 (31.6%) patients lacking any of the following adverse features: ≥pT3b disease, Gleason score ≥9, three or more positive nodes, or positive surgical margin.

Conclusions: For patients with LNM after RP, the use of adjuvant ADT + EBRT improved OS in the majority of patients, especially those with adverse pathological features. Conversely, adjuvant therapy did not confer significant OS benefit in up to 30% of patients without high-risk features, who may be managed with observation and forego the morbidity associated with immediate ADT or radiation.