Exploring the Science of KRAS Gene Testing

Posted by The Evidence Blog on December 12, 2012

By Diane Allingham-Hawkins, PhD, FCCMG, FACMG, Director of the Hayes Genetic Test Evaluation Program

Understanding the intricacies of specific genetic tests is the first step in determining the most cost-effective approach to testing for individuals with suspected genetic diseases. Given the recent explosion of genetic tests, it’s not surprising that our clients often experience coverage policy dilemmas. That’s why Hayes will begin to offer genetic testing algorithms in January 2013. These interactive decision trees are designed to eliminate the guess-work and help our clients to make evidence-based decisions about who should receive these tests. Subscribers to the GTE program will be able to use these algorithms to answer the question, “At what point in the continuum of care is it appropriate to use this test for this patient?”

Take, for example, KRAS gene testing for patients with colorectal cancer. Cancer patients can respond differently to certain cancer therapies, depending on their genetic makeup. Because of this, certain genetic tests can be used to identify patients who are the best suited for a particular cancer treatment. The KRAS gene test can be used to help determine the best treatment options available for patients with advanced colorectal cancer.

The KRAS gene test looks for specific changes in a gene called KRAS that have been linked to differences in treatment response. KRAS gene testing identifies those patients who will not benefit from treatment with medications that reduce the activity of the epidermal growth factor receptor, or EGFR, a protein that promotes tumor growth. These medications include Erbitux® (cetuximab) and Vectibix™ (panitumumab) and are often referred to as anti-EGFR therapies. The KRAS gene test uses DNA, extracted directly from the patient’s tumor, and looks for the presence or absence of specific changes in the KRAS gene.

The KRAS gene test was designed for patients with advanced colorectal cancer who might be treated with anti-EGFR therapy (including cetuximab and panitumumab). If treatment with an anti-EGFR medication is not being considered, this test is not necessary.

Keep in mind that the KRAS gene test is not designed to predict disease outcome (such as the chance of a cure or the length of survival). Also, while KRAS gene testing can identify patients who should not be treated with anti-EGFR therapy, it does not predict how patients who are treated with these medications will respond.

If you’re confused about the proper application of genetic, genomic, and proteomic tests such as the KRAS gene test, rely on Hayes to support your efforts to identify the appropriate use of these tests in specific patient populations.

Topics: Hayes Blog, Genetic Testing

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