Adjuvant radiotherapy in patients with node-positive prostate cancer after radical prostatectomy

Purpose: Our study was to determine whether immediate androgen deprivation therapy (ADT) plus radiotherapy (RT) extends survival in men with node-positive prostate cancer (PCa) after radical prostatectomy (RP) compared with those who received ADT alone.

Methods: A total of 99 consecutive patients with pathological positive lymph nodes (pN1) PCa were included in this study to receive immediate ADT plus RT (n = 70) or to receive immediate ADT alone (n = 29). The primary endpoint was castration-resistant prostate cancer (CRPC) free survival; the secondary endpoints were distant metastasis-free survival. Cox regression was used to assess the independent risk factors for CRPC.

Results: The median follow-up time was 34.0 (24.8, 47.8) months and 34.25 (23.0, 49.0) months, respectively, in the ADT + RT group and ADT-alone group. The 5-year CRPC-free survival rate was 79.5% and 58.3%, respectively, in the ADT + RT group and ADT-alone group (p = 0.308). The 5-year distant metastasis-free survival rate was 71.4% and 38.8, respectively, in the ADT + RT group and ADT-alone group (p = 0.478). Compared with ADT-alone group, we saw a modest, but no significant improvement in CRPC-free survival and distant metastasis-free survival in ADT + RT group. The results of Cox regression showed that positive lymph nodes ≥ 4 was an independent risk factor for CRPC (p = 0.041).

Conclusions: We found that immediate ADT plus RT compared to ADT alone did not improve CRPC-free and metastasis-free survival. Multivariate Cox regression analyses also indicated that patients with positive lymph nodes < 4 may benefits from ADT plus RT.