Comparative analysis of LDR and HDR intracavitary brachytherapy in cervical cancer: the critical role of overall treatment time - a decade of experience.

Background: This study compares low dose rate (LDR) and high dose rate (HDR) intracavitary brachytherapy (ICBT) in the treatment of cervical cancer treated at a tertiary care cancer centre in North India. Materials and methods: A retrospective analysis of 316 cervical cancer patients treated between 2009 and 2019 was conducted. Outcomes of 240 patients receiving external beam radiotherapy (EBRT) followed by HDR were compared with 76 patients treated with a historical group of LDR brachytherapy. Results: The median follow-up was 60 months and 34.4 months for LDR and HDR groups, respectively. Overall treatment time (OTT) was longer in the HDR group and pelvic lymph node positivity was also higher. HDR brachytherapy showed a higher adjusted hazard ratio (HR) for 5-year OS [HR = 2.3, p < 0.001, 95% confidence interval (CI): 1.6-3.3] and local recurrence (HR = 1.5, p = 0.018, 95% CI: 1.07-2.18) compared to LDR. HDR showed higher adjusted HR for 5-year disease-free survival (DFS) (HR = 1.8, p < 0.001, 95% CI: 1.3-2.6). The 5-year OS was 53% in the LDR group and the median survival was not reached, whereas in the HDR group, 5-year OS was 23% with median survival of 34 months. Rectal toxicity was higher in the LDR group. Conclusions: HDR brachytherapy offers clear logistical and patient convenience advantages compared to LDR; however, this benefit comes with the trade-off of higher risks of mortality and relapse when treatment duration is prolonged. Optimizing HDR - through strategies such as reducing OTT and incorporating image guidance - can help mitigate these risks and improve outcomes.