Application of small-pelvic adjuvant radiotherapy in early cervical cancer without high-risk factors after hysterectomy.

OBJECTIVE: To evaluate the clinical efficacy and safety of adjuvant small-pelvic radiotherapy in early-stage cervical cancer patients without high-risk factors following radical hysterectomy. METHODS: Patients were assigned to small pelvic (excluding common iliac nodes) or whole-pelvic radiotherapy groups. Survival was compared before and after propensity score matching. Recursive partitioning analysis was used to construct risk stratification, and sub-group survival was analyzed. Organs-at-risk dosimetry and treatment-related adverse events were also compared. RESULTS: Prior to propensity score matching analysis, whole-pelvic radiotherapy yielded significantly better 5-year disease-free survival than small-pelvic radiotherapy (93.0% vs 86.8%, p = .038), whereas this survival advantage disappeared after propensity score matching adjustment (90.8% vs 87.0%, p = .2). No significant difference in 5-year locoregional control was observed between the two groups after propensity score matching. Three independent risk sub-groups were identified via recursive partitioning analysis. In the high-risk sub-group defined by tumor diameter ≥3.2 cm, whole-pelvic radiotherapy achieved superior survival benefits relative to small-pelvic radiotherapy, with significantly higher 5-year overall survival (96.7% vs 77.1%, p = .022) and disease-free survival (96.7% vs 70.8%, p = .006). Significant inter-group differences were detected in dosimetric metrics of the bone marrow and small intestine, while no obvious difference was found in rectal dosimetry. A borderline significant difference was noted in grade 1-2 gastrointestinal adverse events, with a higher incidence in the whole-pelvic group (26.0% vs 13.7%, p = .06). CONCLUSIONS: Small-pelvic radiotherapy may be less suitable for patients with tumor diameter ≥3.2 cm, while it may reduce mild gastrointestinal toxicities.