Prognostic relevance of the posterior resection margin for predicting disease free survival in ampullary adenocarcinoma. (December 2020) - Schneider, C.
Abstract: Background: Pancreaticoduodenectomy is the only curative treatment option for patients with resectable ampullary adenocarcinoma (AA). Excellent disease free survival (DFS) can be achieved in patients with clear resection margins but it is poorly understood which patients are at increased risk of recurrence and hence would benefit from adjuvant chemotherapy. There is evolving evidence that the anatomical location of incomplete resection margins influences DFS in pancreatic adenocarcinoma. It is unknown if this also pertains to AA and therefore this study aimed to assess individual resection margin status and other predictors of DFS in AA. Material & methods: Consecutive patients undergoing pancreaticoduodenectomy for AA at our institution from 1996 to 2017 were analysed. Pancreas neck, posterior and superior mesenteric vein margins were assessed individually. Cox proportional hazards modelling was used to identify predictors of 5-year DFS. Factors with p < 0.1 on univariate analysis were included for multivariate analysis. Results: Analysis of 104 patients revealed median OS and DFS of 56 and 34 months, respectively. Predictors associated with worse DFS on multivariate analysis were T3-stage (HR 3.6, p = 0.048), N1 (HR 2.9, p = 0.01) and N2 -stage (HR 3.6, p = 0.006), R1 status at the posterior margin (HR 3.0, p = 0.009) and a visible mass on CT (HR 2.0, p = 0.039). Conclusion: Routine histopathological assessment of individual resection margins may aid in predicting recurrence of AA. Future studies to assess if routine mesopancreas excision during pancreaticoduodenectomy can reduce the incidence of R1 status at the posterior margin are warranted. Highlights: The value of examining different resection margins in ampullary carcinoma is unclear. R1 status at the posterior but not the SMV -margin, predicts disease free survival. T-stage, N-stage and visible mass on CT also independently predict disease free survival. Individual margin reporting may identify patients that benefit from adjuvant therapy. Strategies to avoid positive posterior resection margins warrant further evaluation.