PATIENTS with bowel cancer, who were given short-course immunotherapy before surgery, instead of post-operative chemotherapy, remained cancer-free after nearly three years of follow-up, according to new results from the NEOPRISM-CRC trial.
The NEOPRISM-CRC trial
The ongoing trial, presented at the American Association for Cancer Research Annual Meeting 2026 in April, saw 32 patients with stage two or three bowel cancer and MMR deficient/MSI-high bowel cancer from five UK hospitals.
Patients were given up to nine weeks of pembrolizumab before bowel surgery, instead of standard surgery then three to six months of chemotherapy.
Initial results of the trial, led by University College London and University College London hospitals NHS Foundation Trust, found that 59% of patients had no signs of disease after pembrolizumab treatment and their planned surgery.
Latest findings, presented at the American Association for Cancer Research Annual Meeting 2026 in April, build on earlier results showing that nine weeks of pre-operative pembrolizumab immunotherapy led to major tumour shrinkage.
None of the treated patients have experienced relapse now, 33 months later.
This includes those who had no signs of cancer post-treatment and patients who still had small amounts remaining, which did not grow or spread during follow-up.
Dr Kai-Keen Shiu, Chief Investigator of the trial, UCL Cancer Institute, consultant medical oncologist, UCLH, said that results strengthen the case for pembrolizumab as a safe and highly effective treatment to improve high-risk bowel cancer outcomes.
Around 25% of patients who have standard surgery and post-operative chemotherapy are expected to relapse after three years.
Results from the NEOPRISM-CRC trial, however, suggest that a short course of neoadjuvant immunotherapy can provide more durable, long-lasting cancer control for stage two and three bowel cancer, compared with surgery and chemotherapy.
Reference
University College London. Groundbreaking bowel cancer trial follow-up shows zero relapses. 2026. Available at: https://www.ucl.ac.uk/news/2026/apr/groundbreaking-bowel-cancer-trial-follow-shows-zero-relapses. Last accessed: 9 May 2026.
Featured image: Prasit Rodphan on Adobe Stock
