Survival impact of pelvic radiotherapy plus chemotherapy in newly diagnosed stage IVB cervical cancer in Japan (JROSG22-1/JGOG1088S)

PURPOSE: To evaluate the survival benefit of adding pelvic radiotherapy (RT) to chemotherapy and to identify patient subgroups most likely to benefit from pelvic RT. MATERIALS AND METHODS: A multicentre retrospective study was conducted in Japan and included patients with newly diagnosed stage IVB (FIGO 2018) cervical cancer treated with chemotherapy alone or chemotherapy plus pelvic RT between 2016 and 2020. Patients were classified into the CT group (chemotherapy-alone) or PRT group (chemotherapy plus pelvic RT). Propensity score matching (PSM) was applied using age, histology, T stage, N stage, metastatic pattern, and number of metastatic lesions. Overall survival (OS) represented the primary endpoint; progression-free survival (PFS) and late adverse events constituted the secondary endpoints. RESULTS: Among 343 patients, the PRT group showed significantly longer OS than the CT group following PSM (median OS: 25.0 vs. 18.0 months; hazard ratio [HR], 0.58; 95% confidence intervals [CI], 0.42-0.79; p < 0.001). PFS was also significantly improved in the PRT group (HR, 0.65; 95% CI, 0.48-0.87; p = 0.002). The longer OS in the PRT group was seen across metastatic patterns, although this was less evident in early T stages (≤ T2). Brachytherapy was independently associated with improved OS in the PRT group. Grade ≥ 3 gastrointestinal toxicity was more frequent in the PRT group. CONCLUSION: In this nationwide, real-world study, definitive-dose pelvic RT combined with chemotherapy was associated with improved survival in selected patients with stage IVB cervical cancer. Prospective randomised trials are warranted to validate these findings.