AUTHOR=San-Román-Gil María , Martínez-Delfrade Iñigo , Albarrán-Fernández Víctor , Guerrero-Serrano Patricia , Pozas-Pérez Javier , Chamorro-Pérez Jesús , Rosero-Rodríguez Diana , Sotoca-Rubio Pilar , Barrill-Corpa Ana Maria , Alia-Navarro Víctor , González-Merino Carlos , García-de-Quevedo-Suero Coral , López Victoria , Ruz-Caracuel Ignacio , Perna-Monroy Cristian , Ferreiro-Monteagudo Reyes TITLE=Case report: Efficacy of immunotherapy as conversion therapy in dMMR/MSI-H colorectal cancer: a case series and review of the literature JOURNAL=Frontiers in Immunology VOLUME=15 YEAR=2024 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1352262 DOI=10.3389/fimmu.2024.1352262 ISSN=1664-3224 ABSTRACT=

Immunotherapy has demonstrated a role in the therapeutic landscape of a small subset of patients with colorectal carcinoma (CRC) that harbor a microsatellite instability (MSI-H) status due to a deficient DNA mismatch repair (dMMR) system. The remarkable responses to immune checkpoint inhibitors (ICIs) are now being tested in the neoadjuvant setting in localized CRC, where the dMMR/MSI-H status can be found in up to 15% of patients, with remarkable results obtained in NICHE2 and 3 trials, among others. This case series aims to report our experience at a tertiary center and provide a comprehensive analysis of the possible questions and challenges to overcome if ICIs were established as standard of care in a neoadjuvant setting, as well as the potential role they may have as conversion therapy not only in locoregional advanced CRC but also in oligometastatic disease.