Counting on it.

Top Line: Should men with node positive prostate cancer receive adjuvant or early salvage radiation?

The Study: Three large randomized trials have found that adjuvant radiation doesn’t improve event free survival compared to close surveillance and early salvage radiation for localized prostate cancer. However, those trials didn’t really include men with lymph node positive disease. This large study investigated the role of adjuvant or salvage radiation among men with lymph node positive prostate cancer using a cohort of nearly 18,000 men treated with radical prostatectomy (RP) in Hamburg, Germany between 1995 and 2017. Routine extended node sampling was done with a median 12 nodes dissected. Among all patients, 9.0% had positive lymph nodes, and most of those (82%) had 1-3 positive nodes. Among the pN1 patients, 25.5% received adjuvant RT, 41% received early salvage RT, and 33.5% received no RT. The main goal of the study was to compare 7-year all-cause mortality (ACM) risk with adjuvant v salvage RT for every 1-unit increase in the number of positive nodes while accounting for the timing and duration of ADT. They found, not surprisingly, that both the time-dependent use of ADT and the duration of ADT significantly affected ACM risk. In addition, those receiving adjuvant RT were more likely to have PSA>20, pT3b+ disease, and positive margins, and they were more likely to receive adjuvant as opposed to salvage ADT. After adjusting for these effects, they found that adjuvant RT was associated with a lower risk of 7-year ACM compared to salvage RT with a relative 8% reduction in risk for each positive lymph node. Overall, this resulted in a significant reduction in ACM risk among those with ≥4 positive nodes with adjuvant v salvage RT (7.74% v 23.36%), but not for those with 1-3 positive nodes (14.27% v 13.89%).

TBL: For men with node positive prostate cancer, adjuvant radiation may reduce mortality risk with a magnitude of benefit proportional to nodal disease burden. | Tilki, J Clin Oncol 2022