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Low Use of Genomic Tests Among Oncologists for Lung and Colorectal Cancers

August 2017, Vol 7, No 8

The introduction of targeted cancer drugs has revolutionized cancer treatment, especially in patients with colorectal cancer (CRC) or non–small-cell lung cancer (NSCLC). These drugs have been accompanied by genomic assays that test for certain mutations, such as ALK, KRAS, BRAF, or EGFR, which often help guide cancer treatment decisions by identifying patients who would benefit most from certain therapies over others. However, there are few data regarding the real-world use of genomic tests among oncologists for these cancers.

Stacy W. Gray, MD, AM, Associate Clinical Professor, Division of Clinical Cancer Genetics, City of Hope Comprehensive Cancer Center, Duarte, CA, and colleagues examined the use of genomic tests among oncologists in patients with CRC or NSCLC, and found low use of some guideline-endorsed tests, particularly in nonprofit integrative systems.1

“Understanding how genomic testing is used in practice is an essential first step in efforts to ensure that all individuals who can benefit from personalized cancer care receive the testing they need,” stated Dr Gray and colleagues.

They surveyed 337 medical oncologists between 2012 and 2013 about their use of guideline- and nonguideline-endorsed genetic tests in the past 12 months for patients with CRC or NSCLC.

Current guidelines recommend that patients with CRC undergo KRAS testing and patients with NSCLC undergo EGFR testing. Oncologist-reported rates of genomic testing for patients with CRC were higher for KRAS testing than for BRAF testing, germline screening for Lynch syndrome, mismatch repair and/or microsatellite instability, and Oncotype DX testing.

In addition, more patients with NSCLC were tested for EGFR than for ALK, KRAS, or ERCC1. Overall, 32% of oncologists reported testing ≤5 patients for KRAS and EGFR. These results indicate that although more oncologists use guideline-recommended genomic tests than nonguideline-recommended genomic tests, the use of genomic testing remains low.

“This finding is in line with our prior work that suggested that some oncologists may fail to recommend genomic testing even when it is indicated,” stated Dr Gray and colleagues.

Overall, 16% of oncologists reported that patients’ requests were an important factor in influencing their decisions to order genomic testing, and 31% of oncologists reported that they rarely or never discuss the cost of genomic testing with their patients.

Use of Genomic Tests Varies by Practice Type

Ordering genomic tests varied across practice settings. Oncologists who practiced in nonprofit integrated systems reported less guideline-recommended genomic testing compared with oncologists who practiced in hospitals, single-specialty groups, multispecialty groups, or solo practices.

“Some evidence suggests that hospitals or practices with a medical school or teaching affiliation and those that participate in NCI [National Cancer Institute] clinical research cooperative groups may provide guideline-concordant care more frequently than practices without those affiliations,” noted Dr Gray and colleagues.

The low use of genomic testing among oncologists may be attributed to unfamiliarity with testing benefits, a high proportion of patients who may not benefit from testing, inadequate tissue for testing, patient refusal, or lack of access to tests or to clinical trials, the researchers suggested.

Strategies to Improve Genomic Testing Use

Several approaches can be used to reduce the interpractice variation in the use of genomic tests. Widespread reflexive testing for guideline-recommended predictive somatic tests is one approach. Reflexive testing may be particularly useful to identify EGFR mutations in metastatic lung cancer, because EGFR is an actionable mutation.

Another approach is to implement oncologist-directed clinical decision support tools in the electronic health record that recommend genomic testing.

Whether oncologists order germline or somatic tests for their patients, they should have access to guidelines that define the appropriate role of germline and somatic testing in cancer care, emphasized Dr Gray and colleagues.

“Efforts to increase appropriate test use, such as reflexive testing for somatic alterations with known clinical utility, may help to optimize the delivery of precision cancer care,” concluded Dr Gray and colleagues.


  1. Gray SW, Kim B, Sholl L, et al. Medical oncologists’ experiences in using genomic testing for lung and colorectal cancer care. J Oncol Pract. 2017;13:e185-e196.

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