Biomarker testing in patients (pts) with metastatic colorectal cancer (mCRC): Survey of U.S. oncologists (ONC) in rural areas and urban clusters.

Abstract

108 Background: In the US, rural areas have higher cancer mortality rates than urban areas. Clinical practice guidelines recommend testing for BRAF and RAS mutations, and deficient mismatch repair (dMMR)/microsatellite instability (MSI) in pts with mCRC. However, data on biomarker testing rates in rural communities are limited. We surveyed ONC in the US who practice in rural areas and urban clusters to identify biomarker testing patterns and barriers. Methods: A web-based survey was administered to board-certified ONC who spend ≥ 40% of their time providing direct care to pts in rural areas or urban clusters (US Census Bureau definition) and who treated ≥ 2 pts with stage IV mCRC in the month prior to the survey. ONC in Maine, Vermont, and West Virginia were excluded (state legislature), as were those employed by the US government, Veterans Affairs, or Kaiser Permanente. Respondents were compensated. Data were analyzed descriptively. Results: From Feb 12 to Mar 18, 2021, 99 ONC (40% medical ONC, 60% hematologists/ONC) completed the survey. Respondents spent 56% and 18% of their time (mean) practicing in urban clusters and rural areas, respectively; 33% were in the South, followed by 26%, 22%, and 18% in the Northeast, Midwest, and West, respectively. 97% of ONC had ordered biomarker tests for pts; 35% referred pts for independent genomic testing. ONC tested biomarkers most commonly for stage IV disease: 72%, 65%, 63%, 59%, and 66% for KRAS, NRAS, BRAF, PD-L1, and dMMR/MSI, respectively (Table). 41% of ONC reported performing reflex testing at their primary practice, most commonly for PD-L1 (62%), KRAS (60%), and dMMR/MSI (52%). DNA-based next-generation sequencing (NGS) was the most common testing method reported. ONC indicated they would test for an actionable biomarker if it were known to occur in ≥ 28% of pts with mCRC. The most commonly cited barriers to testing were insufficient tissue samples and lack of insurance coverage. Although > 50% of ONC agreed telehealth can improve testing rates, 81% noted barriers, including pts lacking technology equipment (56%) and pts being disengaged or unwilling to use telehealth (37%). Further data on testing-related decision making and barriers will be presented. Conclusions: Biomarker testing in rural areas and urban clusters falls short of current guideline recommendations. Further exploration of rural biomarker testing practices and strategies to improve testing are needed.[Table: see text]