SouthernWorldwide.com – Nearly three years after participating in an experimental immunotherapy trial, all patients diagnosed with bowel cancer have remained cancer-free.
The study, spearheaded by researchers from University College London and UCL Hospitals, suggests that a brief pre-operative immunotherapy regimen could yield superior outcomes compared to the current standard of care for a specific group of patients.
This particular trial involved 32 individuals diagnosed with stage 2 or 3 bowel cancer. According to a press release, these patients presented tumors with a distinct genetic characteristic known as MMR-deficient or MSI-high.
This genetic profile, observed in approximately 10% to 15% of bowel cancer cases, signifies a compromised DNA repair system within the body. Researchers hypothesized that this deficiency might render the tumors more vulnerable to immunotherapy drugs, facilitating their identification and elimination.
Instead of undergoing conventional post-operative chemotherapy, these patients received a drug called pembrolizumab prior to their surgeries. The treatment duration extended up to nine weeks.
Initial data indicated that the drug was remarkably effective in shrinking tumors, to the extent that 59% of patients showed no detectable signs of cancer by the time they underwent surgery.
The most recent findings corroborate these early results, revealing that after a follow-up period of 33 months, none of these patients have experienced a recurrence of the disease. This includes individuals who had residual, albeit non-progressing, traces of cancer following surgery.
“The fact that no patients have experienced a cancer recurrence after nearly three years of follow-up is extremely encouraging,” stated chief investigator Dr. Kai-Keen Shiu, a consultant medical oncologist at UCLH and associate professor at UCL. “This strengthens our confidence that pembrolizumab is a safe and highly effective treatment for improving outcomes in patients with high-risk bowel cancers.”
In contrast, with the traditional approach of surgery followed by chemotherapy, approximately 25% of patients with this specific genetic profile would typically see their cancer return within a three-year timeframe, according to the study.
The research team also employed personalized blood tests to monitor the patients. These tests are designed to detect minute fragments of tumor DNA circulating in the bloodstream, enabling clinicians to assess treatment efficacy before surgery.
“When tumor DNA disappeared from the blood, patients were significantly more likely to have no cancer remaining, and this has aligned with the long-term results we are now observing,” explained first author Yanrong Jiang, a clinical PhD student at the UCL Cancer Institute.
The researchers acknowledged certain limitations within the study. It was conducted on a small cohort of only 32 participants and focused exclusively on a particular genetic subset of patients. Consequently, these findings may not be universally applicable to all individuals diagnosed with bowel cancer.
Furthermore, it is necessary to continue monitoring these patients for an extended period to definitively confirm that the cancer does not return.
Despite these caveats, the researchers expressed optimism regarding the future of personalized cancer care.
“What is particularly exciting is that we may now be able to predict who will respond to the treatment using personalized blood tests and immune profiling,” Dr. Shiu commented.
“These tools could assist us in tailoring our approach, identifying patients who are responding well and might require less therapy before and after surgery.”
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The study’s results were presented at the American Association for Cancer Research (AACR) Annual Meeting 2026, held in San Diego last month.
