Intensity-modulated radiotherapy with systemic chemotherapy improves survival in patients with nonmetastatic unresectable pancreatic adenocarcinoma: A propensity score-matched, nationwide, population-based cohort study

Purpose: In the era of intensity-modulation radiation therapy (IMRT), no prospective randomized trial has evaluated the efficacy of IMRT exclusively, such as concurrent chemoradiotherapy (CCRT), sequential induction chemotherapy followed by radiotherapy (CT-RT), and systemic chemotherapy (CT) alone, for treating unresectable pancreatic adenocarcinomas (PAs) without metastasis. Through propensity score matching, we designed a nationwide, population-based, head-to-head cohort study to determine the effects of various treatments on unresectable PAs. Patients and methods: We minimized the confounding effects of various treatment outcomes in patients with unresectable PAs from the Taiwan Cancer Registry database by dividing them as follows: group 1, CCRT; group 2, sequential CT-RT; group 3, nontreatment; and group 4, CT alone. Results: The matching process yielded a final cohort of 2960 patients (740 patients each in groups 1, 2, 3, and 4). In both univariate and multivariate Cox regression analyses, the adjusted hazard ratios (95% confidence interval) derived for the definitive CCRT and sequential CT-RT groups compared with the CT alone group were 0.443 (0.397–0.495) and 0.633 (0.568–0.705), respectively. Conclusions: A combination of IMRT and systemic CT for the treatment of unresectable PAs might increase survival compared with CT alone.