Biochemical Recurrence in Pathologic T3-4 Prostate Cancer: Indications for Adjuvant Radiotherapy

The study aimed to identify potential candidates for adjuvant radiotherapy by stratifying patients with locally advanced prostate cancer based on their biochemical recurrence (BCR) risk.

This study analyzed data from 3536 men with pT3-4 disease who achieved undetectable prostate-specific antigen (PSA) levels after robot-assisted radical prostatectomy between 2008 and 2023. Kaplan-Meier curves and log-rank tests were used to compare BCR risk across pathologic T (pT) stages. The study also evaluated associations between BCR and other adverse pathologic features, including pathologic grade group (GG), pathologic N (pN) stage, positive surgical margin, perineural invasion, lymphovascular invasion, tumor diameter, and tumor percentage involvement. A multivariable Cox regression was used to adjust for potential confounders, including age, race, Charlson Comorbidity Index, and PSA at biopsy.

The median follow-up period was 60 months (interquartile range [IQR], 24-84 months), with BCR occurring in 852 patients. The patients with pT3b and pT4 disease had higher BCR risk (hazard ratio [HR], 2.54; 95% confidence interval [CI], 2.19-2.94) than those with pT3a disease (HR, 2.10; 95% CI, 1.51-2.93). In the multivariable analysis, the independent predictors for BCR were GG3-5, pT3b, lymphovascular invasion, positive surgical margin, and tumor diameter, with GG5 having the strongest prognostic significance. The combination of GG3-5 and the cumulative number of these adverse features further stratified BCR risk (p < 0.001).

The study demonstrated that patients with GG5 locally advanced disease and multiple adverse pathologic features have the highest BCR risk after achieving undetectable PSA levels. These patients are potential candidates for adjuvant radiotherapy and should receive comprehensive counseling regarding its potential benefits. Prospective studies are warranted to optimize patient selection for adjuvant therapy.