External Radiation Versus Internal Radiation for Patients With Advanced Gastroenteropancreatic Neuroendocrine Neoplasms: A Retrospective Cohort Study.

IntroductionWhile surgical resection is a common treatment for gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), it is frequently unsuitable for advanced cases. Radiation therapy is emerging as a viable alternative. This retrospective cohort study aimed to compare the long-term outcomes of external versus internal radiation in advanced GEP-NENs.MethodsAdvanced GEP-NENs patients diagnosed from 2000 to 2020 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was applied to mitigate selection bias. The Kaplan-Meier method and multivariate Cox proportional hazards models were utilized to evaluate overall survival (OS) and cancer-specific survival (CSS).ResultsA total of 758 patients were enrolled in the study, with 597 receiving external radiation and 161 receiving internal radiation. A higher percentage of older patients, with advanced grades, lymph node metastases, and larger tumors, received external radiation. Before PSM, the OS (P < 0.001) and CSS (P < 0.001) in the external radiation group were worse than those in the internal radiation group. Multivariate Cox analysis also showed that radiation therapy was an independent risk factor affecting OS and CSS in patients with GEP-NENs. After PSM, the OS (P < 0.001) and CSS (P < 0.001) in the external radiation group were still worse than those in the internal radiation group. Multivariate Cox analysis similarly indicated that the prognosis for external radiation was worse than that for internal radiation.ConclusionsOur study suggests a potential survival benefit associated with internal radiation compared to external radiation in advanced GEP-NENs patients.