Adjuvant immune checkpoint inhibitors combined with chemotherapy and lenvatinib for biliary tract cancer after curative resection: A single-center retrospective study.

e16269 Background: Surgery is the cornerstone of curative treatment for biliary tract cancer (BTC), yet only about 30% of patients qualify for resection. Even after surgery, the 3-year recurrence rate approaches 80%, and the BILCAP study shows up to 50% recurrence despite adjuvant therapy. Thus, more effective adjuvant strategies are urgently needed to reduce recurrence after curative therapy. Recent TOPAZ-1 and KN966 results demonstrate that immune checkpoint inhibitors (IO) plus chemotherapy improve BTC survival, while studies of IO combined with GEMOX and lenvatinib show promising efficacy. These data support further evaluation of IO plus chemotherapy and lenvatinib as adjuvant treatment post-surgery. Methods: This single-center, retrospective study enrolled patients with BTC who underwent curative surgery (R0/R1 resection) between July 2021, and December 2025. Eligible patients received adjuvant therapy consisting of immune checkpoint inhibitors (IO) in combination with chemotherapy (GEMOX, capecitabine, or S-1) and lenvatinib, administered according to guideline-recommended dosing. The primary endpoint was relapse-free survival (RFS), while secondary endpoints included overall survival (OS) and safety. Results: A total of 25 patients were included, among whom 16 (64%) were male; the median age was 61 years (range, 42–73). ECOG performance status was 0 in 22 patients (88%) and 1 in 3 patients (12%). Diagnoses included intrahepatic cholangiocarcinoma in 10 cases (40%), extrahepatic cholangiocarcinoma in 9 cases (36%), and gallbladder cancer in 6 cases (24%). Disease stage was stage I in 13 patients (52%), stage II in 3 (12%), stage III in 6 (24%) and stage IV in 3 (12%). Lymph node status was N− in 18 patients and N+ in 7 patients. The proportion of R0 resections was 76%. Treatment regimens included immunotherapy (durvalumab, sintilimab, toripalimab, etc.) plus GEMOX and lenvatinib in 11 patients; immunotherapy plus capecitabine and lenvatinib in 9 patients; and immunotherapy plus S-1 and lenvatinib in 5 patients. The median follow-up duration was 11.7 months. The median number of IO cycles was 10 (range, 1–34), and the median number of chemotherapy cycles was 6 (range, 1–8). Median RFS was 14.8 months, and the 1-year OS rate was 94.74%. Adverse events occurred in 9 patients (36%), with grade ≥3 treatment-related events observed in 20%. Common AEs included myelosuppression, elevated liver enzymes, and hypothyroidism. Conclusions: Adjuvant IO-based therapy with chemotherapy and lenvatinib may delay recurrence after curative resection of BTC, with a favorable safety and tolerability profile. Further prospective studies are warranted to confirm these findings and optimize adjuvant strategies in BTC.