All participants in a study involving bowel cancer patients remained cancer-free nearly three years after undergoing an experimental treatment.
Conducted by researchers at University College London and UCL Hospitals, the study indicates that a brief course of immunotherapy prior to surgery might yield better results than current treatments for certain patients.
The trial examined 32 individuals diagnosed with stage 2 or 3 bowel cancer. These patients possessed tumors demonstrating a particular genetic profile known as MMR-deficient or MSI-high, which occurs in about 10% to 15% of bowel cancer cases. According to researchers, this profile suggests a malfunctioning DNA repair system. Interestingly, this might actually facilitate the action of immunotherapy drugs in targeting tumors more effectively.
Instead of following up their surgeries with typical chemotherapy, these patients were administered a drug called pembrolizumab prior to their operations, with treatment lasting up to nine weeks.
Initial findings showed that the drug was so effective in shrinking tumors that 59% of the patients had no detectable cancer by the time of their surgery.
Now, data from over 33 months indicates that none of these patients have experienced a recurrence of cancer, even those who had small traces remaining post-surgery that did not grow or spread further.
Dr. Kai-Keen Shiu, the lead investigator and a consultant medical oncologist at UCLH, expressed optimism, stating that the absence of cancer recurrence after nearly three years of follow-up is immensely encouraging. He emphasized that it bolsters confidence in pembrolizumab as a safe and effective treatment option for patients with high-risk bowel cancers.
Traditionally, with the standard approach of surgery followed by chemotherapy, around 25% of patients sharing this genetic profile would see their cancer return within a three-year span.
The research team monitored patients using personalized blood tests designed to detect micro-fragments of tumor DNA in the bloodstream, enabling doctors to assess treatment effectiveness before surgery.
When tumor DNA was absent from the blood, patients were likely to have no remaining cancer, a correlation that aligns with the long-term outcomes being reported now.
The researchers did caution about certain limitations—this trial was small, focusing on just 32 patients and a specific genetic subset, which could mean the results are not universally applicable.
Doctors highlighted the need for extended follow-up to ensure that cancer doesn’t return; however, the researchers are enthusiastic about the potential of personalized care in the future.
Shiu noted the exciting possibility of predicting patient responses based on personalized blood tests and immune profiling, which could lead to a tailored approach. This would allow identification of patients who are doing well and might need less intensive therapy to manage their care effectively.
The outcome of this study was recently shared at the American Association for Cancer Research (AACR) Annual Meeting held in San Diego last month.
