No Recurrence in Bowel Cancer Trial After 33 Months
A clinical trial investigating pre-operative immunotherapy for a specific type of bowel cancer has reported that no patients experienced a recurrence of their cancer after a median follow-up of 33 months. The trial, known as NEOPRISM-CRC, was led by researchers from University College London (UCL) and University College London Hospitals (UCLH).
Trial Details
The NEOPRISM-CRC trial involved 32 patients with stage two or three bowel cancer who possess a specific genetic profile known as mismatch repair deficient (MMR deficient) or microsatellite instability-high (MSI-high). This genetic profile is present in an estimated 10-15% of patients with stage two or three bowel cancer, representing approximately 2,000 to 3,000 cases annually in the UK.
Instead of receiving the standard treatment of surgery followed by three to six months of chemotherapy, patients in the trial received up to nine weeks of the immunotherapy drug pembrolizumab prior to surgery. Patients were recruited from five UK hospitals: UCLH, University Hospital Southampton, St. James's University Hospital in Leeds, and the Christie NHS Foundation Trust in Manchester.
Results
Initial results from the trial showed that 59% of patients had no signs of disease after receiving pembrolizumab and undergoing surgery. The latest follow-up data indicates that after a median of 33 months, none of the treated patients have experienced a cancer recurrence. This includes patients who had small residual traces of cancer detected after treatment that did not grow or spread.
Researchers estimate that approximately 25% of patients with this specific genetic profile who receive standard surgery and post-operative chemotherapy relapse within three years.
Research and Monitoring
The research team analyzed blood samples from patients to monitor the treatment's effectiveness. They used personalized blood tests to detect circulating tumor DNA. According to the researchers, the disappearance of tumor DNA from the blood correlated with having no cancer remaining at the time of surgery and matched the long-term outcomes of no recurrence. Immune profiling from tumor tissue taken before treatment was also used to help predict patient response.
Translational work for the trial was conducted by UCL and the biotechnology company Personalis.
Statements from Researchers
Dr. Kai-Keen Shiu, Chief Investigator of the trial from UCL Cancer Institute and UCLH, stated that the results strengthen confidence in pembrolizumab as a treatment. He noted that personalized blood tests and immune profiling may help predict treatment response and tailor approaches for individual patients.
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 that the research team was able to follow patients closely using personalized blood tests. She noted that the disappearance of tumor DNA from the blood matched long-term results.
Patient Case
Christopher Burston, a patient in the trial, was diagnosed with stage three bowel cancer in February 2023. He received three doses of pembrolizumab over nine weeks, followed by surgery in May 2023. Medical imaging indicated the tumor had significantly reduced after immunotherapy. Over three years later, he remains cancer-free.
Limitations and Context
The trial involved a small number of patients (32) and focused on a specific genetic subset of bowel cancer. Researchers note that longer follow-up is needed to confirm that the cancer does not return. The results were scheduled for presentation at the American Association for Cancer Research (AACR) Annual Meeting in April 2026.
Bowel cancer is the fourth most common cancer in the UK, with approximately 44,000 cases diagnosed annually. Five-year survival rates for bowel cancer are reported as approximately 90% for stage one, 65% for stage three, and 10% for stage four.