Adjuvant therapy (AT) in patients (pts) with radically resected ampullary adenocarcinoma (AA): A monocentric retrospective analysis

e16142 Background: Ampullary adenocarcinoma (AA) is a rare tumor. Radical surgery is the only curative treatment for localized AA. The role of AT is not clearly defined and previous evidence in literature is poor and controversial. Hence, we retrospectively analyzed radically resected AA pts at our Institution, investigating the impact of AT on survival and the role of possible prognostic and/or predictive factors. Methods: Radically resected AA pts were retrospectively included in the analysis, divided into two groups: pts receiving AT and pts undergoing only postoperative observation (PO). The following variables were collected: gender; age (≤ 65 vs > 65 years); baseline ECOG PS (0 vs ³ 1); histologic subtype (pancreatobiliary vs intestinal); tumor stage (T1-2 vs T3-4); nodal status (N0 vs N+), margin status (R0 vs R+); radiotherapy (yes vs no), AT regimen [Gemcitabine (GMZ)-based vs fluoropyrimidine (FP)-based treatment)]. The objective of the analysis was to evaluate the impact of AT on overall survival (OS). Univariate and multivariate analyses were performed. Results: From 2007 to 2021, a total of 69 pts with radically resected AA were identified: 41 (59%) pts received AT, 28 (41%) PO. The median age was 65 years (41-81), 42 (61%) were males, ECOG PS was ³ 1 in 45 (65%) pts. Tumor characteristics were: 31 (45%) pancreatobiliary, 26 (38%) intestinal, 9 (13%) mixed subtype and 3 (4%) not available; 41 (59%) pts had T3-T4 stage tumor; 34 (49%) were N+. Out of 41 pts receiving AT, 27 (66%) pts were treated with FP-based AT, 14 (34%) with GMZ-based AT; 16 (23%) pts received also RT. In the overall population, median OS was 59.8 months. At the univariate analysis, there was a statistically significant association of T status with OS (p 0.03), confirmed at multivariate analysis (p 0.03). Further variables (ECOG PS, AT, nodal status and histologic subtype) were not associated with survival. Among the 41 pts receiving AT, median OS was 58.7 months. At the univariate analysis, AT regimen was significantly associated with OS (p 0.02), and it was confirmed at the multivariate analysis. In particular, median OS was 59.8 and 28.3 months in pts receiving FP- and GMZ-based AT, respectively [HR 0.26, (95% CI: 0.09-0.78), p = 0.001]. Conclusions: Among pts with radically resected AA, AT, compared with PO, was not associated with a significant survival benefit. However, among pts receiving AT, FP-based regimen seems to significantly improve OS in comparison to GMZ-based regimen, independently of histologic subtype. Our findings, from a retrospective and limited case series, add to controversial literature data and miss to clarify the real impact of AT in radically resected AA pts. A randomized trial of AT vs PO would provide further information in this setting.