Long-Term Outcomes and Surgical Conversion After Immunotherapy in Microsatellite Instability-H Biliary Tract Cancers.

Authors

Priyanshi Shah, Anina Peersen, Vaibhav Sahai, Amit Mahipal, Nikolas Naleid, Mitesh Borad, Tanios Bekaii-Saab, Mohamad Bassam Sonbol, Umair Majeed, Hani M Babiker, Conor D J O'Donnell, Midhun Malla, Garima Gupta, Caitlyn B Conboy, Lionel Kankeu Fonkoua, Leslie A Washburn, Thorvardur R Halfdanarson, Nicole Peterson, Robert R McWilliams, Ryan M Carr, Rondell P Graham, Patrick Starlinger, Rory Smoot, Susanne Warner, Sumera L Ilyas, Gregory J Gores, Lewis Roberts, Julie Heimbach, Fang-Shu Ou, Nguyen H Tran

Published in

JCO precision oncology. Volume 10. Issue 7. Pages e2501156. Epub Jul 10, 2026.

Abstract

Deficient mismatch repair/microsatellite instability (dMMR, MSI-H) in biliary tract cancers (BTCs) is observed in 1%-5% of tumors. MSI-H across solid tumors has demonstrated durable response to immune checkpoint inhibitors (ICIs) regardless of the anatomic location. Here, we describe clinical outcomes and surgical conversion of MSI-H BTC treated with ICIs.
We conducted a multicenter, retrospective analysis of BTC patients with dMMR/MSI-H between 2017 and 2024 at Mayo Clinic, University of Michigan, and University Hospitals Seidman Cancer Center. Outcomes of interest were surgical resection rate, rate of pathologic response, 2-year overall survival (OS; time from initiation of treatment to death/last follow-up), and time to treatment discontinuation (TTD; time from initiation of treatment to cessation because of any cause). Analyses were descriptive.
Thirty patients with MSI-H BTC were identified: 19 with cholangiocarcinoma, three with gallbladder cancer, and 8 with BTC undefined. The median age at diagnosis was 61.5 years (range, 26-86). Twenty-six (86.7%) patients had advanced stage at diagnosis. Twenty-seven patients (90%) received first-line systemic therapy, and 13 (48.1%) continued onto second line. Six patients (23.1%) were restaged to resectable from advanced disease after ICI therapy and underwent resection; all remained recurrence-free at last follow-up. Of these six patients, 3 (50%) achieved a pathologic complete response. Among those receiving first-line therapy, the median TTD was 9.9 months (95% CI, 5.7 to 14.5 months) and the 2-year OS was 73% (95% CI, 56% to 94%).
ICI therapy in patients with MSI-H BTC demonstrated durable response and downstaged some BTC to a resectable stage. dMMR/MSI-H should be performed up-front to guide treatment decisions.

PMID:
42430699
Bibliographic data and abstract were imported from PubMed on 11 Jul 2026.

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