Overtreatment risk of postoperative radiotherapy in FIGO I–III cervical small cell neuroendocrine carcinoma: a population-based study

Background Cervical small cell neuroendocrine carcinoma (SCNEC) is a rare, highly aggressive cervical malignancy. Radical hysterectomy is standard for localized disease, yet the survival benefit of postoperative radiotherapy (RT) remains controversial. This study assessed postoperative RT’s prognostic impact in SCNEC patients, screened potential RT beneficiaries, and generated evidence to mitigate overtreatment risk. Methods Patients with pathologically confirmed FIGO I–III cervical SCNEC diagnosed between 2000 and 2023 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. All eligible patients underwent radical hysterectomy. Inverse probability treatment weighting (IPTW) balanced baseline features to reduce selection bias. Primary endpoints were overall survival (OS) and cancer-specific survival (CSS). Analyses included weighted Kaplan–Meier curves, multivariate Cox regression, and Fine-Gray competing risk models to evaluate RT’s prognostic effect. Results A total of 175 eligible patients were identified, among whom 96 (54.9%) received surgery combined with postoperative RT and 79 (45.1%) underwent surgery alone. Before IPTW adjustment, no significant differences in OS or CSS were observed between the two groups. After IPTW, weighted survival analyses showed that postoperative RT did not improve OS (hazard ratio [HR]=1.02, 95% confidence interval [CI]: 0.67–1.54, P = 0.101) and CSS (HR = 1.04, 95%CI: 0.70–1.56, P = 0.198) in the overall cohort. Fine-Gray competing risk analysis further showed that postoperative RT was not associated with reduced cancer-specific mortality (HR = 1.11, 95%CI: 0.73–1.69, P = 0.630). Multivariate Cox regression analysis indicated that year of diagnosis and omission of lymph node resection were independent adverse prognostic factors for both endpoints, and stratified analyses showed no measurable heterogeneity of RT effect across all predefined clinical subgroups. Conclusion Postoperative RT was not associated with improved OS or CSS for patients with FIGO stage I–III cervical SCNEC following radical hysterectomy, suggesting a potential overtreatment risk that warrants close clinical attention for this surgically treated population. Given the high malignancy and propensity for systemic metastasis of SCNEC, future studies should focus on integrating immunotherapy strategies targeting the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) axis or delta-like ligand 3 (DLL3) to overcome the limitations of local radiation.