Immune-related adverse events (irAEs) represent a major obstacle in treating solid tumors. This research collects real-world evidence on the frequency of immune-mediated diarrhea and colitis (IMDC) among patients with advanced non-small cell lung cancer (aNSCLC) undergoing immune checkpoint inhibitor (ICI) therapy, while examining how a multidisciplinary approach (MDA) influences IMDC handling and outcomes. Data were retrospectively compiled from sequential aNSCLC patients receiving ICIs alone or combined with chemotherapy from September 2013 through July 2022. For those who developed IMDC, colonic biopsy samples underwent blinded reassessment, and the effects of adopting an MDA were measured against established clinical metrics. Out of 607 enrolled patients, 84 (13.8%) presented with IMDC. Histology re-examination showed frequent microscopic colitis (28%), where collagenous features corresponded to extended symptom persistence (P = .01). IMDC appeared more often in women (P = .05) and those with PD-L1-positive tumors (P = .014), and it was associated with extended progression-free survival (17.0 vs 5.8, P < .001) as well as overall survival (28.3 vs 9.5, P < .001). Adopting the MDA led to higher utilization of diagnostic procedures, including fecal calprotectin assays (P < .001), colonoscopies (P < .001), and gastroenterologist consultations (P = .017), together with notable reductions in progression to grade 3 severity (P = .046) and relapse upon ICI rechallenge (P = .016). Hospital admissions fell from 17.2% to 3.8% (P: ns). The data emphasize the substantial clinical burden of IMDC and advocate integrating an MDA to refine management of this irAE, thereby advancing patient outcomes. A prospective study for confirmation is underway.
