Survival benefit of radiotherapy in pancreatic cancer A real-world analysis based on SEER and an independent hospital-based cohort.

[BACKGROUND] Pancreatic cancer remains one of the most lethal malignancies worldwide, and the role of radiotherapy in improving prognosis remains controversial. This study aimed to assess the survival benefit of radiotherapy in pancreatic cancer patients using real-world population data.

[METHODS] We extracted clinical data of pancreatic cancer patients diagnosed between 2019 and 2021 from the SEER database. After applying strict inclusion and exclusion criteria, 22,735 patients were included. Propensity score matching (PSM) at a 1:2 ratio was performed to balance baseline characteristics between radiotherapy and non-radiotherapy groups, followed by Kaplan-Meier survival analyses and multivariate Cox proportional hazards modeling. Interaction effects between radiotherapy and key clinical variables were further explored. An independent hospital-based cohort of 175 patients from Hunan Provincial People's Hospital was included to assess reproducibility.

[RESULTS] Among 22,735 patients, 3,100 (13.6%) received radiotherapy. Prior to PSM, radiotherapy was associated with significantly improved median overall survival (HR = 0.65; 95% CI: 0.61-0.68; P<0.0001). This survival benefit remained consistent post-PSM (HR = 0.69; 95% CI: 0.65-0.73; P<0.0001). Multivariate Cox analysis confirmed radiotherapy as an independent protective factor for OS (P<0.001), along with surgery and chemotherapy. Significant interaction effects were observed between radiotherapy and tumor histology, clinical stage, and surgery status (P<0.05 for all). Stratified survival curves demonstrated that the survival benefit of radiotherapy was most pronounced in patients with stage III-IV, those who did not undergo surgery, and those with adenocarcinoma histology. In contrast, the hospital-based cohort showed no statistically significant difference in OS between the two groups (P = 0.35), although similar trends were observed.

[CONCLUSIONS] Radiotherapy was associated with a significant and independent survival benefit among pancreatic cancer patients in the SEER cohort, particularly in patients with stage III and IV, adenocarcinoma, and non-surgical subgroups. However, this survival advantage was not observed in the hospital-based cohort, suggesting that the generalizability of the benefit warrants further investigation in larger, independent populations.