biostudies-literaturePapke DJNational Cancer InstituteNCI NIH HHS1746-1751https://www.ebi.ac.uk/biostudies/studies/S-EPMC9444979biostudies-literatureUnknown31(9)<h4>Background</h4>In 2017, DNA mismatch repair/microsatellite instability (MMR/MSI) testing was nationally recommended for advanced colorectal cancers based on favorable immune checkpoint inhibitor responses among patients with MMR-deficient/MSI-high tumors.<h4>Methods</h4>Patients ages ≥20-years-old presenting with stage IV colorectal adenocarcinoma from 2010 to 2017 were identified from the National Cancer Database. 2017 was the latest year with available testing utilization data. Patient, tumor, socioeconomic, and care setting characteristics were evaluated for association with upfront MMR/MSI testing in 2017 using multivariable logistic regression and average adjusted predicted probabilities (%AAP).<h4>Results</h4>Among 72,830 stage IV colorectal cancers, upfront MMR/MSI testing levelCancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive OncologyUnderutilization of Guideline-Recommended Mismatch Repair/Microsatellite Instability Biomarker Testing in Advanced Colorectal Cancer.PMC9444979K12 CA090354P30 CA008748K12CA090354Schrag DLindeman NIPapke DJIorgulescu JBfalseUnderutilization of Guideline-Recommended Mismatch Repair/Microsatellite Instability Biomarker Testing in Advanced Colorectal Cancer.<h4>Background</h4>In 2017, DNA mismatch repair/microsatellite instability (MMR/MSI) testing was nationally recommended for advanced colorectal cancers based on favorable immune checkpoint inhibitor responses among patients with MMR-deficient/MSI-high tumors.<h4>Methods</h4>Patients ages ≥20-years-old presenting with stage IV colorectal adenocarcinoma from 2010 to 2017 were identified from the National Cancer Database. 2017 was the latest year with available testing utilization data. Patient, tumor, socioeconomic, and care setting characteristics were evaluated for association with upfront MMR/MSI testing in 2017 using multivariable logistic regression and average adjusted predicted probabilities (%AAP).<h4>Results</h4>Among 72,830 stage IV colorectal cancers, upfront MMR/MSI testing level2022-01-01T00:00:00Z2022 Sep2025-04-19T13:31:40.478Z2025-04-19T13:31:40.478ZS-EPMC94449793576797610.1158/1055-9965.EPI-22-027910.1158/1055-9965.epi-22-0279