Survival Benefit of Adjuvant Chemotherapy After Pancreatoduodenectomy for Ampullary Adenocarcinoma: a Propensity-Matched National Cancer Database (NCDB) Analysis

Abstract

Background: The benefit of adjuvant chemotherapy (AC) after pancreatoduodenectomy (PD) for ampullary adenocarcinoma is uncertain. We aimed to evaluate the association of AC with survival in patients with resected ampullary adenocarcinoma. Methods: Using the National Cancer Database (NCDB) data from 2004 to 2016, patients with non-metastatic ampullary adenocarcinoma who underwent PD were identified. Patients with neoadjuvant radiotherapy and chemotherapy and survival < 6 months were excluded. Propensity score matching was used to account for treatment selection bias. A multivariable Cox proportional hazards model was then used to analyze the association of AC with survival. Results: Of 3186 (43%) AC and 4172 (57%) no AC (noAC) patients, 1720 AC and 1720 noAC patients remained in the cohort after matching. Clinicopathologic variables were well balanced after matching. After matching, AC was associated with improved survival (median 47.5 vs 39.6 months, p = 0.003), which remained after multivariable adjustment (HR: 0.83, CI95%: 0.76–0.91, p < 0.001). Multivariable interaction analyses showed that this benefit was seen irrespective of nodal status: N0 (HR: 0.81, CI95%: 0.68–0.97, p < 0.001), N1 (HR: 0.65, CI95%: 0.61–0.70, p < 0.001), N2 (HR: 0.73, CI95%: 0.59–0.90, p = 0.003), N3 (HR: 0.59, CI95%: 0.44–0.78, p < 0.001); and margin status: R0 (HR: 0.85, CI95%: 0.77–0.94, p < 0.001), R1 (HR: 0.69, CI95%: 0.48–1.00, p < 0.001). Stratified analyses by nodal and margin status demonstrated consistent results. Conclusion: In this large retrospective cohort study, AC after resected ampullary adenocarcinoma was associated with a survival benefit in patients, including patients with node-negative and margin-negative disease.