BACKGROUND The role of adjuvant chemotherapy (AC) in patients with ampullary adenocarcinoma (AA) remains controversial. This study aimed to determine if AC could improve the prognosis of patients with resected AA.

STUDY DESIGN This study enrolled patients diagnosed with AA at 9 tertiary teaching hospitals. Patients who did and did not receive AC were matched 1:1 using propensity score. The overall survival (OS) and recurrence-free survival (RFS) were compared between the 2 groups.

RESULTS Of the 1,057 patients with AA, 883 underwent curative-intent pancreaticoduodenectomy, and 255 received AC. Because patients with advanced-stage AA received AC more frequently, the no AC group unexpectedly had a longer OS (not reached vs 78.6 months; p < 0.001) and RFS (not reached vs 18.7 months; p < 0.001) than did the AC group in the unmatched cohort. In the propensity score-matched cohort (n = 296), no difference between the 2 groups in terms of OS (95.9 vs 89.8 months, p = 0.303) and RFS (not reached vs 25.5 months; p = 0.069) was found. By subgroup analysis, patients with advanced stage (pT4 or pN1-2) showed longer OS in the AC group than in the no AC group (not reached vs 15.7 months, p = 0.007: 89.8 vs 24.2 months, p = 0.006, respectively). There was no difference in RFS according to AC in the propensity score-matched cohort.

CONCLUSIONS Given its favorable long-term outcomes, AC can be recommended for patients with resected AA, especially those in the advanced stage (pT4 or pN1-2).