New HER2 Testing Guidelines

Breast cancer patients recommended to be tested for HER2 status

(RxWiki News) Two leading professional medical societies have joined forces to issue a new recommendation for all newly diagnosed invasive breast cancer patients. The aim of these guidelines is to improve precision treatment of an aggressive form of the disease.

The American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) are now recommending that every individual diagnosed with breast cancer undergo testing for HER2.

HER2 stands for human epidermal growth factor receptor 2 (HER2).

About 15 percent of all breast cancer tumors have high levels of HER2 protein or the HER2 gene. These cancers tend to grow faster and be more aggressive than tumors that don’t have HER2 abnormalities.

"Talk to your oncologist about molecular testing for your cancer."

Antonio C. Wolff, MD, FACP, FASCO, professor of oncology at the Johns Hopkins Kimmel Comprehensive Cancer Center, was co-chair of the ASCO/CAP HER2 Testing in Breast Cancer Panel.

The new guidelines are an update of 2007 recommendations.

Dr. Wolff said in a prepared statement, “Our ability to identify cancer subtypes that will lead to more individualized therapeutic decisions and that are shown to improve clinical outcomes is rapidly improving. Consequently, and more than ever before, society must demand access to high-quality cancer biomarker tests that can help cancer specialists match the right treatments with the right patients.”

There are currently two HER2 tests approved by the US Food and Drug Administration (FDA): immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH).

According to ASCO, IHC testing shows how much HER2 protein is present on the tumor cell surface, while FISH testing measures the number of copies of the HER2 gene inside each cancer cell.

Another HER2 test called bright-field ISH is also available. This test uses a regular light microscope to measure the amplification of the HER2 gene.

The purpose of testing, the two organizations said in a statement, is to “...identify patients who could benefit from effective HER2-targeted therapies, such as trastuzumab (Herceptin), lapatinib (Tykerb), pertuzumab (Perjeta), and T-DM1 (Kadcyla)."

These medications target HER2 and have been shown to extend the lives of patients with HER2 breast cancer.

The organizations have issued these new recommendations:

  • All newly diagnosed invasive breast cancer patients should undergo HER2 testing, using either IHC or ISH technique.
  • If the results of one test are unclear, retesting should be done using an alterative test.
  • If tests results are positive for HER2 abnormalities, the oncologist should discuss anti-HER2 treatment options with the patient.
  • HER2 targeted therapy should not be given to patients whose HER2 tests are negative.
  • The oncologist should rely only on accredited testing laboratories.

The updated guidelines also encourage physicians to discuss with patients the importance of HER2 testing, the types of tests and their interpretation, the need for retesting in new or metastatic (has spread) tumors.

These new guidelines were published October 7 in the Journal of Clinical Oncology.

A number of the panel members disclosed financial relationships with Roche, the manufacturer of Herceptin, Kadcyla and Perjeta, Genomic Health and Clarient – GE Heath.

Review Date: 
October 7, 2013