A recent study compared the clinical outcomes of postoperative adjuvant radiotherapy versus early-salvage radiotherapy administered to patients with stage pT3 prostate cancer or those with positive margins.
Results of the study were published in JAMA Oncology (online January 25, 2018; doi:10.1001/jamaoncol.2017.5230).
Prostate cancer with adverse pathological features (eg, pT3 and positive margins) after prostatectomy may be managed with adjuvant radiotherapy or surveillance followed by early-salvage radiotherapy for biochemical recurrence. However, the optimal timing of postoperative radiotherapy remains uncertain.
William L Hwang, MD, PhD, department of radiation oncology, Massachusetts General Hospital, and colleagues conducted a study to determine the optimal timing of postoperative radiotherapy for patients with prostate cancer and with these adverse pathological features. The multi-institutional, propensity score-matched cohort study included 1566 patients who underwent either post-prostatectomy adjuvant radiotherapy or early-salvage radiotherapy at 10 US academic medical centers from 1987 through 2013. Propensity score 1-to-1 matching was used to account for covariates associated with treatment selection.
Researchers assessed for post-irradiation biochemical failure, freedom from distant metastases, and overall survival. Among the total patient population, 1195 patients with prostate-specific antigen levels lower than 0.1 ng/mL received early-salvage radiotherapy and 371 patients with prostate-specific antigen levels of 0.1 to 0.5 ng/mL received adjuvant radiotherapy.
Results of the study showed that adjuvant radiotherapy was associated with higher freedom from biochemical failure (12-year actuarial rates, 69% vs 43%) freedom from distant metastases (95% vs 85%), and overall survival (91% vs 79%), compared with early-salvage radiotherapy.
Additionally, researchers found that adjuvant radiotherapy, lower Gleason score and T-stage, nodal irradiation, and postoperative androgen deprivation therapy were favorable prognostic features on multivariate analysis for biochemical failure.
Dr Hwang and colleagues noted that these findings need to be validated in prospective studies. Nonetheless, they concluded that “a greater proportion of patients with prostate cancer who have adverse pathological features may benefit from post-prostatectomy adjuvant radiotherapy rather than surveillance followed by early-salvage radiotherapy.”—Zachary Bessette