e15585 Background: Microsatellite instability–high (MSI-H) colon cancer represents a distinct molecular subset with prognostic and therapeutic implications particularly in the era of immunotherapy. However, real-world data from community oncology settings in India remains limited. Methods: This retrospective study evaluated MSI-H colon cancer patients from March 2018 to May 2025 at Western India community oncology centers. PFS and OS were analyzed using Kaplan-Meier. Results: A total of 1100 colon cancer patients were evaluated out of which 358 underwent MSI testing most patients had an ECOG PS of 0–1 (87.8%) 95% CI, NA–NA) (p = 0.001). Median PFS was 25.9 months (95% CI, 15.96–35.8) in MSI-stable cohort vs 71.9 months (95% CI, 0.0–168.02) in the MSI-H cohort (p = 0.006). Conclusions: This real-world analysis from Western India identifies MSI-H colon cancer as a biologically distinct entity with right-sided predominance and superior survival outcomes; however, underutilization of MSI testing and immunotherapy underscores the need for systematic MSI assessment to facilitate timely, biomarker-driven treatment in community oncology settings.
Maniar et al. (Thu,) studied this question.