Pre-surgery pembrolizumab linked to zero recurrences in a small bowel cancer trial

In a 32-patient trial of stage 2–3 bowel cancer with MMR-deficient/MSI-high tumors, a short course of pembrolizumab before surgery kept all patients cancer-free for nearly three years; early data showed 59% had no signs of cancer at surgery, and long-term follow-up found no recurrences, a result that may surpass standard chemotherapy for this subset but is limited by size and specificity. Researchers also used tumor DNA blood tests to monitor response and aim to predict who will benefit. Presented at AACR 2026; longer follow-up is needed.