Adjuvant radiation has shown promise in recent studies for men with prostate cancer who had unfavorable pathological characteristics. Researchers anticipated that observation followed by early salvage radiation may still be an option for a subgroup of patients with unfavorable characteristics who do not benefit from adjuvant radiotherapy. 

From 1987 to 2020, a total of 8,362 patients were treated with radical prostatectomy at a single hospital. Of them, 926 were found to have unfavorable pathology features (i.e., grade group 4-5 with ≥pT3a stage and/or lymph node invasion). Each feature was given a score using Cox models. After classifying patients into low, middle, and high risk categories using inverse probability of treatment weighting, interaction term analyses were performed to determine the efficacy of adjuvant radiation for each risk subgroup. 

Of all patients, 538 (58%) underwent adjuvant radiation, 89 (10%) underwent early salvage radiotherapy, and 299 (32% were observed). In the long run, 90% of people survived past the first decade. There was a statistically significant interaction between high-risk group and adjuvant radiation (HR 0.21, P =.04). Survival analyses showed that low and intermediate risk patients treated with adjuvant radiation or observation followed by early salvage treatment had similar 10-year overall survival after risk categorization and propensity-score weighting. Adjuvant radiation, on the other hand, was linked to significantly better 10-year overall survival compared to observation  ± early salvage radiotherapy (76% vs 63%, P =.038) in high-risk patients. 

They found 3 distinct risk groups among patients with unfavorable pathological characteristics. The only individuals who looked to benefit from adjuvant radiotherapy were those in the high-risk category, when comparing it to observation with or without early salvage treatment for survival.