In a study reported in JCO Precision Oncology, Gutierrez et al found that most patients in a U.S. sample diagnosed with metastatic colon cancer between 2013 and 2017 did not receive guideline-aligned genomic testing for RAS, BRAF, and microsatellite instability/mismatch repair–deficiency (MSI/dMMR) aberrations. The findings are consistent with earlier reports indicating suboptimal adherence to testing guidelines.
Study Details
The study involved 1,497 patients with pathologically confirmed metastatic colon cancer diagnosed between January 2013 and December 2017 identified from electronic health records in the COTA Real World Data database. Patients were treated at 23 practices in the United States, including both community (n = 345, 23%) and academic centers (n = 1,152, 77%). Not all testing guidelines applied to all patients during the entire period examined.
“Despite guideline recommendations and significant therapeutic implications, overall biomarker testing rates in [metastatic colon cancer] remain suboptimal. Adherence to guideline-recommended biomarker testing would potentially reduce exposure to expensive and ineffective therapies, resulting in improved patient outcomes.”— Gutierrez et al
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Key Findings
Guideline-aligned testing for RAS, BRAF, and dMMR was performed in 41% (610 of 1,497), 43% (235 of 546), and 51% (276 of 546) of patients to whom guidelines applied during the period examined.
Guideline-aligned RAS testing was more likely among patients treated at an academic center vs community center (44% vs 29%, P < .001), those presenting with de novo metastatic disease vs progressing from an earlier stage (43% vs 25%, P <.001), those diagnosed at age < 65 years vs ≥ 65 years (44% vs 35%, P < .001), and female vs male patients (45% vs 37%, P < .01).
Guideline-aligned BRAF testing was more likely among patients treated at an academic center vs community center (47% vs 25%, P < .001), those presenting with de novo metastatic disease vs progressing from an earlier stage (46% vs 23%, P < .001), and female vs male patients (48% vs 38%, P < .05). Greater likelihood of guideline-aligned dMMR testing was not associated with any factors examined in the study.
Among 177 patients (12% of population) who received anti-EGFR therapy, 50 (28%) had complete guideline-aligned biomarker testing.
The investigators concluded, “Despite guideline recommendations and significant therapeutic implications, overall biomarker testing rates in [metastatic colon cancer] remain suboptimal. Adherence to guideline-recommended biomarker testing would potentially reduce exposure to expensive and ineffective therapies, resulting in improved patient outcomes.”
Stuart L. Goldberg, MD, of the John Theurer Cancer Center, Hackensack University Medical Center, and Cota Healthcare, New York, is the corresponding author for the JCO Precision Oncology article.
Disclosure: The study was supported by Guardant Health. For full disclosures of the study authors, visit ascopubs.org.
