What are the American College of Clinical Oncology and the College of American Pathologists guidelines on HER2 testing in breast cancer?

Updated: May 14, 2019
  • Author: Maurie Markman, MD, MS; Chief Editor: Karl S Roth, MD  more...
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Answer

Answer

ERBB2 is a transmembrane tyrosine kinase receptor and a member of the ErbB protein family (ie, the epidermal growth factor receptor [EGFR] family). ERBB2 is most commonly known as HER2 and sometimes also as NEU. For this article, it will be referred to as HER2. HER2 gene product is overexpressed in 18-20% of invasive breast cancers. [1]

The American Society of Clinical Oncology and the College of American Pathologists issued the following updated recommendations for HER2 testing in breast cancer [2] :

  • HER2 status should be determined in all patients with invasive breast cancer on the basis of 1 or more test results.

  • HER2-positive status is indicated by evidence of protein overexpression or gene amplification.

  • When results are equivocal, reflex testing should be performed with an alternative assay, and repeat testing should be considered if results are discordant with other findings.

  • Laboratories should be able to show high concordance with a validated HER2 test on a large and representative set of specimens, and testing must be performed in an accredited laboratory.

  • Providers should recommend HER2-targeted therapies if the patient's HER2 test result is positive and such treatment is clinically appropriate. Most experts do not recommend HER2-targeted therapy if the HER2 test result is negative and there is no histopathologic discordance with HER2 testing. Delay the decision to recommend HER2-targeted therapy if the HER2 test result is equivocal. Reflex testing should be done on the same specimen.

These recommendations have also been adapted and studied in other countries, such as England, France, and Italy. [3, 4, 5]


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