Chemotherapy combined with iodine-125 seed implantation versus seed implantation alone for pelvic recurrence of cervical cancer following radiotherapy: a single-centre retrospective comparative cohort study

Objective To determine whether the addition of chemotherapy is associated with longer survival in patients with pelvic recurrence of cervical cancer following radiotherapy who undergo Iodine-125 (¹²⁵I) brachytherapy. Methods This single-centre retrospective comparative cohort study analysed survival outcomes and their determinants in patients with pelvic recurrence of cervical cancer treated with ¹²⁵I seed implantation at Yichang Second People’s Hospital between January 2019 and June 2024. Patients were stratified into a brachytherapy-alone group (Group A, n = 22) and a brachytherapy combined with chemotherapy group (Group B, n = 16). In total, 25 deaths were recorded (Group A: 15; Group B: 10). Overall survival was assessed using Kaplan–Meier analysis with log-rank testing, and factors independently associated with overall survival were identified using multivariable Cox proportional hazards regression. Post-hoc sensitivity analyses examined the influence of baseline extrapelvic metastases and age imbalance on the primary results. Results Median overall survival was 36 months in Group B and 16 months in Group A (log-rank P = 0.021). In the primary multivariable Cox regression model, pelvic tumour size (HR = 1.721, 95% CI: 1.272–2.328, P < 0.001) and combination chemotherapy (HR = 0.293, 95% CI: 0.115–0.745, P = 0.010) were independently associated with overall survival. Local tumour response was excluded from the primary model as a post-baseline variable that may partly reflect the chemotherapy effect. In a sensitivity analysis excluding 2 patients with baseline extrapelvic metastases ( n = 36), the association between combination chemotherapy and longer overall survival remained materially unchanged (HR = 0.300, 95% CI: 0.117–0.768, P = 0.012). After additional adjustment for age, this association was attenuated (HR = 0.366, 95% CI: 0.132–1.018, P = 0.054). Conclusion ¹²⁵I brachytherapy combined with chemotherapy was associated with longer overall survival in patients with pelvic recurrence of cervical cancer following radiotherapy. However, given the retrospective design, limited sample size, and potential for selection bias, this association should not be interpreted as evidence of treatment efficacy. The findings are most relevant to settings in which bevacizumab and immune checkpoint inhibitors are unavailable or unsuitable and warrant validation in prospective, multi-centre studies.