Pre-Surgery Immunotherapy Shows Promise for Durable Bowel Cancer Control
A clinical trial investigating a short course of immunotherapy before surgery for a specific type of bowel cancer has reported that none of the treated patients have experienced a cancer recurrence after 33 months of follow-up.
The findings, based on a 32-patient study, suggest this approach may offer durable cancer control for patients with a particular genetic profile.
Trial Design and Key Results
The NEOPRISM-CRC clinical trial involved 32 patients with stage two or three bowel cancer characterized as MMR deficient or MSI-high. Participants received up to nine weeks of the immunotherapy drug pembrolizumab prior to surgery, instead of the standard treatment of surgery followed by chemotherapy.
Initial trial results showed that 59% of patients had no signs of disease after the pre-operative treatment and subsequent surgery. The latest data, with a median follow-up of 33 months, indicates that none of the patients in the trial have experienced a cancer recurrence to date.
Researchers estimate that approximately 25% of patients receiving standard surgery and post-operative chemotherapy for this cancer stage relapse within three years.
Background and Patient Population
Bowel cancer is the fourth most common cancer in the United Kingdom, with around 44,000 cases diagnosed annually. The MMR deficient/MSI-high genetic profile targeted in this trial is present in an estimated 10-15% of patients with stage two or three bowel cancer. This equates to roughly 2,000-3,000 cases per year in the UK.
Supporting Research and Analysis
As part of the trial, researchers conducted analyses to understand treatment effectiveness and identify predictive markers:
- Personalized blood tests were designed to detect cancer DNA in the bloodstream. Researchers reported that the disappearance of tumour DNA from the blood correlated with having no cancer remaining after treatment and matched the long-term outcomes.
- Immune profiling from tumour tissue samples taken before treatment began was also analyzed and may help predict which patients are likely to respond to the immunotherapy.
The translational work for this aspect of the trial was conducted by University College London (UCL) and the biotechnology company Personalis.
Researcher Statements
Trial investigators provided the following statements regarding the findings:
- Dr. Kai-Keen Shiu, Chief Investigator from UCL Cancer Institute and University College London Hospitals (UCLH), stated the results are encouraging and strengthen confidence in pembrolizumab as a safe and effective treatment. He noted that personalized blood tests and immune profiling may help predict treatment response and tailor approaches.
- Professor Marnix Jansen, leading the translational research from UCL Cancer Institute and UCLH, said the results confirm the durability of responses and provide biological insights into why immunotherapy is effective in this context.
- Yanrong Jiang, first author of the latest abstract and a clinical PhD student at UCL Cancer Institute, stated the research team was able to follow patients closely using personalized blood tests and that these tests may help guide treatment decisions.
Trial Logistics and Presentation
The trial was led by a team from UCL and UCLH. Patient recruitment also involved University Hospital Southampton, St. James's University Hospital in Leeds, and the Christie NHS Foundation Trust in Manchester.
The latest findings are scheduled for presentation at the American Association for Cancer Research Annual Meeting in April 2026.