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Uptake of KRAS Testing and Anti-EGFR Antibody Use for Colorectal Cancer in the VA
Daniel J Becker1,2, Kyung M Lee3, Steve Y Lee4
1NYU Grossman School of Medicine, New York, NY.
Abstract:
Advances in precision oncology, including RAS 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 KRAS molecular testing, guideline recommended since 2010, in the Veterans Affairs Healthcare System (VA).
Materials And Methods:
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, KRAS testing, and EGFR mAb treatment.
Results:
Among 5,943 patients diagnosed with stage IV CRC, only 1,053 (17.7%) had KRAS 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 v < 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 KRAS 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 KRAS wild-type (WT) went untreated with EGFR mAb and 8.8% (401/4,570) with no KRAS testing received EGFR mAb. Among KRAS-WT patients, survival was better for patients who received EGFR mAb treatment (29.6 v 18.8 months; P < .001).
Conclusion:
We found underuse of KRAS 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 KRAS-WT tumors. Efforts to understand barriers to precision oncology are needed to maximize patient benefit.
Insights
KRAS testing for colorectal cancer (CRC) is underused, especially in older patients. Guideline-discordant care, including not using EGFR mAb for KRAS wild-type tumors, was frequent, impacting patient survival.
Area of Science:
- Oncology
- Molecular Diagnostics
- Health Services Research
Background:
- Precision oncology advances, like RAS testing for colorectal cancer (CRC), improve patient outcomes.
- KRAS molecular testing is recommended for predicting response to epidermal growth factor receptor monoclonal antibodies (EGFR mAbs).
Purpose of the Study:
- To evaluate the uptake and clinical use of KRAS molecular testing in the Veterans Affairs Healthcare System (VA).
- To assess the association between patient characteristics and KRAS testing.
- To identify rates of guideline-discordant care regarding EGFR mAb treatment in advanced CRC patients.
Main Methods:
- Retrospective cohort study of stage IV CRC patients in the VA (2006-2015).
- Data collected from VA Corporate Data Warehouse and commercial laboratories.
- Multivariable analyses used to examine associations between patient factors, KRAS testing, and EGFR mAb treatment.
Main Results:
- Only 17.7% of 5,943 stage IV CRC patients underwent KRAS testing, with rates increasing from 2.3% (2006) to 28.4% (2013).
- Older patients and those at lower-volume CRC centers were less likely to be tested.
- High rates of guideline-discordant care observed: 64.3% of KRAS wild-type (WT) patients did not receive EGFR mAb, and 8.8% of untested patients did.
Conclusions:
- KRAS testing is underutilized in advanced CRC, particularly among older patients and those treated at lower-volume centers.
- Significant rates of guideline-discordant underuse of EGFR mAb for KRAS-WT tumors were found.
- Further research is needed to address barriers to precision oncology and maximize patient benefits.
