S18 Ep43: Neoadjuvant Immunotherapy and Short Treatment Courses Drive Paradigm Shifts in CRC Management

The treatment of colorectal cancer is undergoing a paradigm shift as neoadjuvant immunotherapy moves to the forefront of clinical practice. Dr. Pashtoon Kasi, Medical Director of GI Medical Oncology at City of Hope, highlights how mismatch repair deficient (MSI-high) tumors exhibit exceptional sensitivity to checkpoint blockade, often resulting in complete pathological responses. Recent clinical trials, including the NICHE and NEST studies, demonstrate that brief courses of neoadjuvant immunotherapy are feasible and effective, even in mismatch repair proficient (MSS) tumors, by modulating the tumor microenvironment. Furthermore, the integration of circulating tumor DNA (ctDNA) as a biomarker provides a precise, real-time assessment of minimal residual disease. These advancements offer promising alternatives to traditional surgery-first approaches, particularly for younger patients facing rising rates of early-onset colorectal cancer, where maximizing curative potential remains the primary clinical objective.