Abstract
BACKGROUND: Adjuvant immunotherapy has improved outcomes in patients with advanced melanoma; however, the potential benefit for patients with pancreatic ductal adenocarcinoma (PDAC) remains unknown. The aim of this study was to determine the impact of adjuvant chemotherapy and immunotherapy (CTx-IT) compared with CTx alone on patient survival after resection of PDAC. STUDY DESIGN: Patients who underwent resection of PDAC from 2004 to 2015 were identified from the National Cancer Database. Univariate and multivariate Cox proportional hazards models were used to determine predictors of overall survival (OS) based on the type of adjuvant therapy received. Patients who received adjuvant immunotherapy were compared with those who received adjuvant CTx alone by propensity score matching. RESULTS: Of 21,313 patients who received curative-intent resection for PDAC followed by adjuvant systemic therapy, 269 (1.3%) patients were treated with adjuvant CTx-IT. Propensity score matching resulted in a cohort of 477 patients: (229 CTx only and 248 CTx-IT). The 5-year OS was higher in the CTx-IT group compared with CTx alone (29.2% vs 18.3%; p = 0.0045). On multivariate analysis, the addition of adjuvant immunotherapy was associated was improved overall survival (hazard ratio 0.74; p = 0.007). CONCLUSIONS: The addition of adjuvant immunotherapy to chemotherapy is associated with improved survival compared with chemotherapy alone after curative-intent resection of pancreatic adenocarcinoma. Future research is warranted to match specific immunotherapy agents with susceptible patient populations to improve outcomes for this aggressive disease.