Retrospective study of disparities in biomarker testing among patients with metastatic colorectal cancer

Among patients with metastatic colorectal cancer (mCRC), data are limited on disparate biomarker testing and its associations with clinical outcomes on a national scale. A retrospective study using the National Cancer Database included 41,061 patients with mCRC diagnosed between 2010 and 2017. Among these patients, 28.8% received KRAS testing and 43.7% received MSI testing. Factors associated with a reduced likelihood of microsatellite instability and KRAS testing between diagnosis and first –course therapy were older age, treatment at community facilities, lower educational level in area of residence, and treatment at South Central regional facilities. Receiving MSI-testing was associated with overall survival improvement (HR 0.93; p<0.001). The authors conclude that findings of this study highlight the sociodemographic-based disparities in biomarker testing, which can inform the development of strategies that promote equity in cancer care and improve outcomes for underserved populations.