COMPARATIVE OUTCOMES OF RADIATION TREATMENT MODALITIES FOR PROSTATE CANCER IN A RESOURCE-LIMITED SETTING

Background: Prostate cancer remains a major malignancy in sub-Saharan Africa, where access to advanced radiotherapy is limited.

Objective: This study compares biochemical recurrence-free survival (bRFS) and toxicity outcomes among prostate cancer patients who received external beam radiotherapy (EBRT) alone, high-dose-rate brachytherapy (HDRBT) monotherapy, or combined EBRT+HDRBT at West Africa’s first Prostate HDR brachytherapy centre.

Methods: This retrospective cohort study included 109 prostate cancer patients treated at University College Hospital, Ibadan, Nigeria, from January 2020 to December 2023. Patients were grouped by modality: EBRT alone (n=67), HDRBT monotherapy (n=24), and EBRT+HDR BT (n=18). Biochemical recurrence was defined per Phoenix criteria (nadir PSA+2ng/mL). Toxicity was graded using the Common Terminology Criteria for Adverse Events v5.0. Kaplan-Meier analysis estimated bRFS, with log-rank test for comparisons and multivariable Cox regression for predictors. Logistic regression assessed toxicity predictors. p < 0.05 was denoted as significant.

Results: Median follow-up was 21 months (range:6-42 months). Kaplan-Meier estimated bRFS at 30 months was 41.7%, 56.5% and 84.4% for HDRBT, EBRT and EBRT+HDRBT, respectively (p=0.075). Multivariable Cox analysis identified the Gleason score as the only significant predictor (HR=1.34, 95% CI:1.07-1.69; p=0.012). EBRT+BT had better biochemical control compared to EBRT. (HR=0.30, 95% CI:0.09-1.06; p=0.061). ≥Grade 2 toxicity was lower in BT (4.2%) compared to EBRT (35.8%) and EBRT+HDRBT (27.8%; p<0.001), with HDRBT associated with reduced odds (AOR=0.069, 95% CI:0.008-0.609; p=0.016).

Conclusion: In this LMIC cohort, combined EBRT+HDRBT showed a non-significant trend toward improved bRFS compared to EBRT alone, and significantly better outcomes than BT monotherapy. HDRBT monotherapy offered the best tolerability.