Comparative Overall Survival and Time to Progression Across Four HDR Brachytherapy Fractionation Regimens in Locally Advanced Cervical Cancer: A Retrospective Cohort Study at UCH Ibadan, Nigeria

BACKGROUND Locally advanced cervical cancer represents the dominant presentation in sub-Saharan Africa, where radiotherapy remains the primary curative modality. High-dose-rate (HDR) intracavitary brachytherapy is an essential component of definitive chemoradiation; however, the optimal fractionation schedule in resource-limited settings remains debated. This study compared overall survival and time to disease progression across four HDR brachytherapy fractionation regimens delivered with external beam radiotherapy at a tertiary radiotherapy centre in Nigeria. METHODS A retrospective cohort analysis was conducted on 116 patients with histologically confirmed FIGO stage IIB–IIIB uterine cervical cancer treated at the University College Hospital (UCH), Ibadan. All patients received EBRT of 45 Gy in 12 alternate-day fractions with HDR intracavitary brachytherapy using the intrauterine-and-ring applicator. Patients were stratified into Group I (3 fractions (#) ×4 Gy), Group II (3 fractions(#) ×5 Gy), Group III (3fractions(#) ×6.5 Gy), and Group IV (3 fractions(#) ×7 Gy). Kaplan-Meier analysis, log-rank tests, and Bonferroni-corrected pairwise comparisons were performed using IBM SPSS Statistics version 25. RESULTS The mean age was 53.9 ± 11.3 years. The 32-month overall survival for the cohort (n=114) was 65.8%. Group-specific survival rates were 35.3%, 50.0%, 83.3%, and 85.7% for Groups I–IV, respectively (p < 0.05). Pairwise comparisons confirmed significant survival differences between lower dose HDR brachytherapy regimens and higher dose HDR brachytherapy regimens. Median time to disease progression was 6.0, 8.0, 15.0, and 24.0 months across Groups I–IV (p = 0.144). CONCLUSION Higher-dose HDR brachytherapy fractionation regimens conferred significantly superior overall survival. Group IV (3×7 Gy) achieved the best outcomes with a total EQD2 meeting the American Brachytherapy Society recommended range of 80–90 Gy, supporting protocol revision toward higher-dose-per-fraction schedules in resource-constrained settings.