Objectives To examine the benefits of extended-field chemoradiation with simultaneous integrated boost to positive lymph nodes, followed by image-guided adaptive brachytherapy in patients with cervical cancer with para-aortic metastasis.

Methods This retrospective cohort study enrolled 143 patients diagnosed between January 2011 and July 2023 at a single center. Survival and recurrence were evaluated using the Kaplan-Meier method and log-rank test. Cox regression was employed to identify prognostic factors and adjust for confounding factors. Patients were then stratified according to neoadjuvant chemotherapy, and its impact on survival outcomes was evaluated.

Results A total of 129 patients completed the entire treatment course. The 5-year overall survival rate was 57.6%, and the para-aortic failure rate was 6.8% after a median follow-up of 61 months (95% CI 49 to 82 months). Multivariate analysis indicated that neoadjuvant chemotherapy, larger primary tumor or pelvic/para-aortic lymph nodes, and lower hemoglobin nadir (for widespread metastasis-free survival only) predicted poorer survival. After propensity score matching, the 5-year para-aortic recurrence-free, widespread metastasis-free, and overall survival rates were 92.2% vs 92.8% (p=0.85), 50.8% vs 72.1% (p=0.007), and 47.5% vs 65.5% (p=0.037), respectively, in groups receiving neoadjuvant chemotherapy or not. Sixteen patients (12.4%) experienced grade 3–4 late toxicities. Patients who received neoadjuvant chemotherapy had a significantly higher incidence of grade 3–4 anemia and neutropenia than those who did not (45.2% vs 26.7% and 38.1% vs 21.8%, respectively), if including another 14 patients who discontinued treatment due to acute vomiting.

Conclusion Chemoradiation with simultaneous integrated boost to positive lymph nodes demonstrates favorable outcomes and acceptable late toxicities in para-aortic metastatic cervical cancer. Neoadjuvant chemotherapy has been shown to adversely affect outcomes, and acute vomiting is a major cause of treatment abortion.