Comparison of Frontline FOLFIRINOX with Fluorouracil-Based and Gemcitabine-Based Chemotherapies in Metastatic Ampullary Adenocarcinoma: A Multicenter Study by the Turkish Oncology Group (TOG).

Background: Adenocarcinoma arising from the ampulla of Vater is an extremely rare neoplasm, and there are limited data regarding frontline therapy for metastatic disease. We investigated the outcomes of first-line treatment with FOLFIRINOX by comparing it with other treatments in patients with advanced ampullary adenocarcinoma. Methods: We included 123 patients with advanced ampullary adenocarcinoma who were treated with frontline FOLFIRINOX (n = 32), fluorouracil (FU)-based chemotherapy (n = 20), and gemcitabine-based chemotherapy (n = 65) between August 2007 and January 2024 in this retrospective study. The median progression-free survival (mPFS) and overall survival (mOS) according to treatment and clinicopathological features were calculated using the Kaplan-Meier method. Results: The median age of the patients was 62 years (range, 36-78), and 75,6% of the patients had an ECOG performance status of 0-1. The mOS were 13 months (95% CI, 10.6-14.4), 11 months (95% CI, 10.6-14.4), and 12 months (95% CI, 10.6-14.4), respectively [p = 0.865]. There were no significant differences in OS among the chemotherapeutic agents according to histological subtypes. However, FOLFIRINOX and FU-based treatments appeared more effective in the intestinal subtype, while gemcitabine-based therapies were less effective. In the pancreaticobiliary subtype, FU-based therapies yielded a shorter outcome compared to FOLFIRINOX and gemcitabine-based therapies. Grade 3 or 4 hematologic toxicities were higher in patients treated with FOLFIRINOX. Conclusions: In advanced ampullary adenocarcinoma, despite higher toxicity, frontline FOLFIRINOX showed a trend toward an OS benefit in the intestinal subtype while providing a similar outcome in the pancreaticobiliary subtype.