Uptake of KRAS Testing and Anti-EGFR Antibody Use for Colorectal Cancer in the VA

• Published in: JCO precision oncology Vol. 5
• Main Authors: Becker, Daniel J, Lee, Kyung M, Lee, Steve Y, Lynch, Kristine E, Makarov, Danil V, Sherman, Scott E, Morrissey, Christy D, Kelley, Michael J, Lynch, Julie A
• Format: Journal Article
• Language: English
• Published: United States 2021
• Subjects: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal - therapeutic use; Cohort Studies; Colorectal Neoplasms - diagnosis; Colorectal Neoplasms - drug therapy; Colorectal Neoplasms - genetics; ErbB Receptors - antagonists & inhibitors; Female; Genetic Testing; Humans; Male; Middle Aged; Proto-Oncogene Proteins p21(ras) - genetics; Retrospective Studies; Veterans Health Services
• ISSN: 2473-4284
• DOI: 10.1200/PO.20.00359

Advances in precision oncology, including
testing to predict response to epidermal growth factor receptor monoclonal antibodies (EGFR mAbs) in colorectal cancer (CRC), can extend patients' lives. We evaluated uptake and clinical use of
molecular testing, guideline recommended since 2010, in the Veterans Affairs Healthcare System (VA).
We conducted a retrospective cohort study of patients with stage IV CRC diagnosed in the VA 2006-2015. We gathered clinical, demographic, molecular, and treatment data from the VA Corporate Data Warehouse and 29 commercial laboratories. We performed multivariable analyses of associations between patient characteristics,
testing, and EGFR mAb treatment.
Among 5,943 patients diagnosed with stage IV CRC, only 1,053 (17.7%) had
testing. Testing rates increased from 2.3% in 2006 to 28.4% in 2013. In multivariable regression, older patients (odds ratio, 0.17; 95% CI, 0.09 to 0.32 for ≥ age 85
< 45 years) and those treated in the Northeast and South regions were less likely, and those treated at high-volume CRC centers were more likely to have
testing (odds ratio, 2.32; 95% CI, 1.48 to 3.63). Rates of potentially guideline discordant care were high: 64.3% (321/499) of
wild-type (WT) went untreated with EGFR mAb and 8.8% (401/4,570) with no
testing received EGFR mAb. Among
-WT patients, survival was better for patients who received EGFR mAb treatment (29.6
18.8 months;
< .001).
We found underuse of
testing in advanced CRC, especially among older patients and those treated at lower-volume CRC centers. We found high rates of potentially guideline discordant underuse of EGFR mAb in patients with
-WT tumors. Efforts to understand barriers to precision oncology are needed to maximize patient benefit.