A Model for Predicting DNA Mismatch Repair-deficient Colorectal Cancer

Abstract

Background/aim: Identifying patients with DNA mismatch repair-deficient (dMMR) colorectal cancer (CRC) is vital to improve treatment and identify patients with Lynch syndrome (LS). We developed a prediction model for dMMR CRC using clinicopathologic features.

Patients and methods: We reviewed the medical records of 1,147 patients who underwent resection of stage I-IV CRC in whom universal screening for LS using immunohistochemistry for MMR proteins had performed. Univariate and multivariate logistic regression analyses were used to build a prediction model of dMMR CRC.

Results: The prevalence of dMMR CRC was 5.2%. Age (≥75 years), tumor location (right-sided colon), main histologic features (poor differentiation), maximum tumor size (≥65 mm), and stage (I/II) were independent significant variables related to dMMR. We created a formula for predicting the likelihood of dMMR, and the probability ranged from 0.2% to 83%.

Conclusion: dMMR CRC can be identified efficiently using clinicopathologic features obtained in daily clinical practice.

Keywords: Defective mismatch repair; Lynch syndrome; anti-PD-1 blockade; colorectal cancer; microsatellite instability.