HER2 test guidelines change, benefit uncertain

Longtermsurvivor

Updated Testing Guidelines Make More Women Eligible for Herceptin, Yet Benefit Uncertain

ROCHESTER, Minn. -- Changes to HER2 testing guidelines for breast cancer in 2013 significantly increased the number of patients who test HER2-positive, according to a new study by Mayo Clinic researchers published in the Journal of Clinical Oncology. Cancers that have an excess of HER2 protein or extra copies of the HER2 gene are called HER2-positive and can be treated with drugs like Herceptin that target HER2. HER2 stands for human epidermal growth factor receptor 2. (Journal of Clinical Oncology)

--Mayo Clinic

http://www.newswise.com/articles/view/658042/?sc=sptn

excerpt:

ewswise — ROCHESTER, Minn. — Changes to HER2 testing guidelines for breast cancer in 2013 significantly increased the number of patients who test HER2-positive, according to a new study by Mayo Clinic researchers published in the Journal of Clinical Oncology. Cancers that have an excess of HER2 protein or extra copies of the HER2 gene are called HER2-positive and can be treated with drugs like Herceptin that target HER2. HER2 stands for human epidermal growth factor receptor 2.

Mayo Clinic researchers found that the number of HER2-positive breast cancers doubled after testing guidelines were changed by the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) in 2013. "The new guidelines were established to reduce the number of equivocal cases, where HER2 status is uncertain, but we found that they did just the opposite," says senior study author Robert Jenkins, M.D., Ph.D., the Ting Tsung and Wei Fong Chao Professor of Individualized Medicine Research and Professor of Laboratory Medicine and Pathology at Mayo Clinic. "The number of equivocal cases went up, resulting in additional testing and a much larger number of women with cancers ultimately labeled as HER2-positive.

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In their analysis, the researchers found a near doubling in the proportion of HER2 FISH-positive cases interpreted using AC2013 (23.6 percent), compared to the FDA criteria (13.1 percent) or AC2007 (11 percent). The Mayo researchers previously reported a 13 percent HER2-positivity rate using the FDA criteria in their clinical practice in 2000, and that rate had remained constant until the implementation of AC2013. Since the implementation of AC2013, an additional 10-15 percent of women with breast cancer are considered eligible for HER2-directed therapies, even though it is unknown if they would benefit from addition of HER2-directed treatments.

"Women who receive false positive results are not only exposed to the risks of HER2-directed therapies, but they also miss out on the treatments that could be effective against their cancer. That is counter to the goal of personalized medicine, which is to give the right drug to the right patient at the right time," says Dr. Jenkins. "Given the medical, financial and psychosocial aspects of these targeted therapies, it is prudent that we prospectively identify the most optimal candidates for treatment."