New bowel cancer immunotherapy treatment ‘highly effective’ in improving survival rates

A groundbreaking new treatment regime for bowel cancer patients which involves immunotherapy before surgery has shown remarkable success in improving survival rates and significantly reducing the need for chemotherapy.

Research suggests zero relapses among patients receiving this innovative approach, far exceeding expected outcomes from conventional methods.

The trial, led by University College London (UCL) and University College London Hospitals NHS Foundation Trust (UCLH), presented its findings at the American Association for Cancer Research (AACR) meeting in San Diego, California.

It builds on earlier work demonstrating that a nine-week course of pre-operative immunotherapy using the drug pembrolizumab led to substantial tumour shrinkage in individuals with stage two or three bowel cancer.

Crucially, 59% of patients exhibited no signs of disease following pembrolizumab treatment and their subsequent planned bowel cancer operation.

Now, 33 months later, none of these patients have experienced a return of their cancer.

This includes those who were disease-free post-treatment and even those who initially had small amounts of residual cancer, which did not grow or spread during the follow-up period.

This outcome stands in stark contrast to standard treatment, where approximately a quarter of patients undergoing surgery and post-operative chemotherapy typically see their cancer return within three years.

The NEOPRISM-CRC trial involved 32 patients with stage two or three bowel cancer and a specific genetic profile (MMR deficient/MSI-high), recruited from five hospitals across the UK, highlighting the potential for a far more effective treatment pathway.

Around 10-15% of patients with stage two or three bowel cancer have this genetic profile, making up around 2,000-3,000 bowel cancer cases per year in the UK.

While the study looked at this specific group of patients, researchers are hopeful their approach can be extended to others with bowel cancer.

Dr Kai-Keen Shiu, chief investigator from the UCL Cancer Institute and a consultant medical oncologist at UCLH, said: “Seeing that no patients have experienced a cancer recurrence after almost three years of follow-up is extremely encouraging and strengthens our confidence that pembrolizumab is a safe and highly effective treatment to improve outcomes in patients with high-risk bowel cancers.

“What is particularly exciting is that we now may be able to predict who will respond to the treatment using personalised blood tests and immune profiling.

“These tools could help us tailor our approach, identifying patients who are doing well and may need less therapy before and after surgery versus patients at higher risk of disease progression or relapse who need additional treatment.”

Patients were given up to nine weeks of pembrolizumab prior to bowel surgery, instead of the usual treatment of surgery followed by three to six months of chemotherapy, then monitored over time.

UCLH patient Christopher Burston was diagnosed with bowel cancer in February 2023 after taking part in routine screening.

Mr Burston, 73, of Portland, Dorset, received three doses of immunotherapy over nine weeks, followed by surgery.

He said: “The outcome of the surgery was essentially that the cancer had melted away – these were the doctor’s words.

“The immunotherapy had had an almost immediate effect.”

Over three years later, he remains cancer-free.

“The recovery went fine,” he said. “I didn’t have any problems. And since then, I’ve been feeling pretty much back to normal.

“I feel very lucky that I’ve reached the stage where my main problem is age rather than cancer or any illness.

“I am able to play guitar, tend my garden and walk the dog very much as before and I look forward to spending time with friends and family.”