Colon Cancer Breakthrough: Immunotherapy Before Surgery Keeps Patients Cancer-Free for Nearly 3 Years

<p>A groundbreaking clinical trial is rewriting the rulebook for colorectal cancer treatment — with results that have stunned even the researchers behind it.</p><h2>Zero Relapses After Nearly Three Years</h2><p>In the <strong>NEOPRISM-CRC study</strong>, led by researchers at University College London (UCL) and University College London Hospitals (UCLH), patients with stage two or three colorectal cancer received just <strong>nine weeks of pembrolizumab</strong> (an immunotherapy drug) before undergoing surgery.</p><p>The results are extraordinary: <strong>59% of patients had no detectable cancer</strong> after completing immunotherapy and surgery. And after 33 months of follow-up, <strong>not a single patient has relapsed</strong> — including those who still had small traces of cancer after treatment.</p><h2>Why This Matters</h2><p>Under standard care — surgery followed by months of gruelling chemotherapy — approximately <strong>25% of patients</strong> see their cancer return within three years. The NEOPRISM approach appears to offer dramatically better protection with far less treatment burden.</p><p>Bowel cancer is the <strong>fourth most common cancer in the UK</strong>, with around 44,000 new cases annually. While it primarily affects older adults, diagnoses among people under 50 have been rising steadily.</p><h2>Personalised Blood Tests</h2><p>The research team also developed personalised blood tests that can detect whether cancer DNA is still circulating in the bloodstream — potentially allowing doctors to determine early whether treatment has been successful.</p><p>Dr Kai-Keen Shiu, Chief Investigator of the trial, said: <em>"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."</em></p><h2>Who Could Benefit?</h2><p>The trial focused on patients with a specific genetic subtype called <strong>MMR deficient/MSI-high</strong> bowel cancer, which accounts for about <strong>10-15% of cases</strong> — roughly 2,000 to 3,000 patients each year in the UK alone.</p><p>The findings were presented at the <strong>American Association for Cancer Research (AACR) Annual Meeting 2026</strong> in San Diego, marking a major milestone in the shift toward immunotherapy-first cancer treatment.</p><p><em>Sources: University College London, ScienceDaily, AACR Annual Meeting 2026 (May 6, 2026)</em></p>