CONCLUSIONS AND RELEVANCE: In this cohort study, adjuvant (m)FOLFIRINOX and other multiagent chemotherapy regimens were associated with improved OS following resection of localized pancreatic adenocarcinoma after preoperative (m)FOLFIRINOX, whereas single-agent adjuvant chemotherapy was not. The impact of adjuvant chemotherapy on OS may be lower in subgroups such as patients with 8 or more preoperative cycles of (m)FOLFIRINOX, those having radiological response, and those with …