A recent article in the Journal of Clinical Oncology recommends to oncologists that all patients with invasive breast cancer, including recurrent disease, should be tested for HER 2 status and these tests should adhere to specific criteria to define positive, equivocal, and negative results.

The American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) have released updated recommendations for HER2 testing in breast cancer. The new guideline endorses HER2 testing for every primary, recurrent, and metastatic tumor. Additionally, the report advocates retesting in patients who previously tested HER2-negative but demonstrate clinical behavior suggestive of HER2-positive or triple-negative disease at the time of recurrence.

HER2 is a protein involved in normal cell growth. It is  found on some types of cancer cells, including breast and ovarian. Cancer   cells removed from the body may be tested for the presence of HER2/neu to   help decide the best type of treatment. HER2/neu stands for human epidermal   growth factor receptor 2. The accurate identification of patients with  HER2-positive breast cancer remains an area of high interest, since   HER2-targeted therapies can substantially improve their survival.

The first test ideally should be performed on a core biopsy specimen from a patient with newly diagnosed breast cancer. If there is discordance, a section of the tumor from the excisional specimen should be tested. If this test is negative and concerns remain, the updated guideline recommends retesting in a different block from the patient’s tumor. If all three tests are negative, no additional testing is recommended

This is an update of guidelines previously published in 2007. The update does not represent a dramatic overhaul but instead clarifies test criteria, definitions, and processes, said Eric Weiner, MD, a breast cancer specialist in the Susan F Smith Center for Women’s Cancers at Dana Farber Cancer Institute.  “What this guideline states is that if more than 10% of the tumor meets the criteria for HER2 positivity, than it is called HER2 positive.”

Primary Source: Journal of Clinical Oncology