Potential Suboptimal Use of Guideline-Endorsed Genomic Testing in Non–Small Cell Lung and Colorectal Cancers


Key Points

  • Many oncologists reported no MMR/MSI or germline Lynch syndrome testing in colorectal cancer patients and no ALK testing in NSCLC patients.
  • Genetic testing rates were lower in nonprofit integrated health-care delivery systems vs other settings and higher among high-volume oncologists.

In a study reported in the Journal of Oncology Practice, Gray et al found that many medical oncologists did not use genomic testing endorsed by guidelines in place in 2012 and 2013 in patients with non–small cell lung cancer (NSCLC) and colorectal cancer.

The study involved a survey of U.S. medical oncologists caring for patients in diverse practice and health-care settings in 2012 and 2013. Of the oncologists invited to participate, 337 of them (53%) completed the survey. Among them, 86% and 84% reported treating patients with colorectal cancer and NSCLC, respectively, within the prior 12 months.

Likelihood of Testing

Oncologists reported a higher use (P < .001) of guideline-endorsed tests (eg, KRAS for colorectal cancer and EGFR for NSCLC) than non–guideline-endorsed tests (eg, Oncotype DX Colon and ERCC1 for NSCLC). In patients with colorectal cancer, testing rates were higher for KRAS than for guideline-endorsed screening for Lynch syndrome (ie, mismatch repair [MMR] proteins by immunohistochemistry/microsatellite instability [MSI] testing), somatic BRAF testing, and germline Lynch syndrome testing, and nonendorsed Oncotype DX Colon. In patients with NSCLC, testing rates for EGFR were higher than those for guideline-endorsed ALK and KRAS and nonendorsed ERCC1.

A sizable proportion of oncologists reported that no patients with colorectal cancer had MMR/MSI testing (24%) or germline Lynch syndrome testing (32%) and that no patients with NSCLC had ALK testing (11%); 32% reported that ≤ 5 patients had KRAS and EGFR testing for colorectal cancer and NSCLC. Oncologists ordered genetic testing far more frequently than did pathologists or surgeons, and more patients of higher-volume vs lower-volume oncologists underwent genetic testing.

In multivariable analysis, fewer patients in nonprofit integrated health-care delivery systems underwent testing than did patients in hospital or office-based single-specialty group settings (P = .004 for a trend in colorectal cancer, P < .001 for a trend in NSCLC). High patient volume (incidence rate ratio [IRR] = 1.36, P < .001, for colorectal cancer; IRR = 1.31, P < .001, for NSCLC) and patient requests (colorectal cancer only; P = .02 for trend) were also associated with a greater likelihood of testing.

The investigators concluded: “Genomic test use for [colorectal cancer] and NSCLC varies by test and practice characteristics. Research in specific clinical contexts is needed to determine whether the observed variation reflects appropriate or inappropriate care. One potential way to reduce unwanted variation would be to offer widespread reflexive testing by pathology for guideline-endorsed predictive somatic tests.”

The study was supported by National Cancer Institute grants, the American Cancer Society, and the National Human Genome Research Institute.

Stacy W. Gray, MD, of the City of Hope Comprehensive Cancer Center, is the corresponding author of the Journal of Oncology Practice article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.