Survival benefits and disparities in radiation therapy for elderly patients with pancreatic ductal adenocarcinoma

BACKGROUND: Older patients represent a unique subgroup of the cancer patient population, for which the role of cancer therapy requires special consideration. However, the outcomes of radiation therapy (RT) in elderly patients with pancreatic ductal adenocarcinoma (PDAC) are not well-defined in the literature. AIM: To explore the use and effectiveness of RT in the treatment of elderly patients with PDAC in clinical practice. METHODS: Data from patients with PDAC aged ≥ 65 years between 2004 and 2018 were collected from the Surveillance, Epidemiology, and End Results database. Multivariate logistic regression analysis was performed to determine factors associated with RT administration. Overall survival (OS) and cancer-specific survival (CSS) were evaluated using the Kaplan–Meier method with the log-rank test. Univariate and multivariate analyses with the Cox proportional hazards model were used to identify prognostic factors for OS. Propensity score matching (PSM) was applied to balance the baseline characteristics between the RT and non-RT groups. Subgroup analyses were performed based on clinical characteristics. RESULTS: A total of 12245 patients met the inclusion criteria, of whom 2551 (20.8%) were treated with RT and 9694 (79.2%) were not. The odds of receiving RT increased with younger age, diagnosis in an earlier period, primary site in the head, localized disease, greater tumor size, and receiving chemotherapy (all P < 0.05). Before PSM, the RT group had better outcomes than did the non-RT group [median OS, 14.0 vs 6.0 mo; hazard ratio (HR) for OS: 0.862, 95% confidence interval (CI): 0.819–0.908, P < 0.001; and HR for CSS: 0.867, 95%CI: 0.823–0.914, P < 0.001]. After PSM, the survival benefit associated with RT remained comparable (median OS: 14.0 vs 11.0 mo; HR for OS: 0.818, 95%CI: 0.768–0.872, P < 0.001; and HR for CSS: 0.816, 95%CI: 0.765–0.871, P < 0.001). Subgroup analysis revealed that the survival benefits (OS and CSS) of RT were more significant in patients aged 65 to 80 years, in regional and distant stages, with no surgery, and receiving chemotherapy. CONCLUSION: RT improved the outcome of elderly patients with PDAC, particularly those aged 65 to 80 years, in regional and distant stages, with no surgery, and who received chemotherapy. Further prospective studies are warranted to validate our results.