We know immunotherapy works in MSI-H colorectal cancer. The question is, how long do we actually need to treat patients? Well, grateful we’re finally getting some answers ahead of #ESMO2026 A new multicenter study from China published in @jitc evaluated 129 patients with dMMR/MSI-H CRC who achieved a clinical complete response to PD-1 inhibition and pursued non-operative management. 66 stopped treatment, 63 continued maintenance. At 3 years: ▪️DFS: 96.2% vs 98.3% (p=0.508) ▪️OS: 100% vs 98.3% ▪️Only 2 local regrowths, both in the observation group and both successfully salvaged. ▪️No distant metastases. Meanwhile, 15.9% of patients continuing maintenance developed grade ≥2 treatment-related toxicity during maintenance. But what actually constitutes a complete response? Radiographically, patients may have persistent abnormalities due to fibrosis rather than viable tumor. In my practice, I use ctDNA and biopsy, alongside imaging and endoscopy, to help guide these decisions. A residual mass doesn’t necessarily mean residual cancer. Yes, China only. Yes, retrospective. And importantly, these were predominantly patients with localized disease who achieved cCR, not all patients with mCRC. I’ve been using these data in abstract form to guide discussions with patients almost weekly. In fact, I was literally discussing this study with a colleague a few hours ago, without realizing the full paper had come out (@patel_riya7 ). We know immunotherapy can produce durable responses. Maybe we don’t need to keep treating patients for years… @OncoAlert @TheGutOncLab jitc.bmj.com/content/14/10/e…