Abstract: Background and purpose: Until now, treatment regimen following R0 resection in pancreatic cancer patients is uncertain. The aim of this study was to evaluate the efficacy and toxicity of adjuvant radiotherapy in combination with chemotherapy, and the prognostic factors for metastasis-free survival (MFS) in the setting of multidisciplinary approach strategies. Methods: Eighty-eight patients with pancreatic cancer after R0 resection treated in Fudan University Shanghai Cancer Center from Dec. 2011 to Jun. 2018 were included in the analysis. They were treated with adjuvant radiotherapy at a median dose of 50.4 Gy given by 1.8-2.0 Gy/fraction to the tumor bed and elective nodal regions. The adjuvant chemotherapy included systematic chemotherapy and regional intra-arterial infusion chemotherapy (RIAC). Systematic chemotherapy was administered to all of 88 patients, and RIAC to 63 of 88 patients. Toxicity and patterns of failure were evaluated. Univariate and multivariate analyses were conducted to investigate the prognostic factors for MFS. Results: The patients tolerated the treatment well with 3.4% of Grade 1, 12.5% of Grade 2, 60.2% of Grade 3 and 23.9% of Grade 4 toxicities, respectively. At the last follow-up visit, failures were found in 68 patients, including 58 distant metastases. Among them, the liver was the most common site (23/88). The median overall survival (OS) and MFS were 27.0 and 19.9 months, 1-, 3- and 5-year OS rates were 85.1%, 30.4% and 24.6%, and 1- and 3-year MFS were 77.5% and 28.0%, respectively. Univariate analysis revealed that adjuvant radiotherapy combined with RIAC was significantly associated with longer MFS compared with adjuvant radiotherapy without RIAC (25.4 months vs 14.9 months, P=0.036), and RIAC was also confirmed as the independent favorable factor for longer MFS by multivariate analysis (P=0.048). Conclusion: The combination of adjuvant radiotherapy and chemotherapy was safe, and yielded encouraging efficacy for R0 resected pancreatic cancer. Patterns of treatment failure were dominated by distant metastasis, and liver was the most common site of metastasis. Adding RIAC to the combination therapy further improved the MFS, and could be integrated into the adjuvant chemoradiotherapy.

Key words: Pancreatic cancer, Adjuvant radiotherapy, Regional intra-arterial infusion chemotherapy, Metastasis-free survival