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Cancer Groups Release New Guideline on HER2 Testing for Breast Cancer Patients

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December 3, 2013

The American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) have joined forces to issue an updated guideline on testing for human epidermal growth factor receptor 2 (HER2) in patients with invasive breast cancer. The updated guideline is based on a review of published studies and was conducted by experts in breast cancer and cancer biomarkers.

About 20% of all people with newly diagnosed breast cancers have tumors that are HER2-positive. This means that the cancers have extra copies of the HER2/neu gene (amplification) and/or high levels of the HER2 protein (over-expression). HER2-positive tumors usually grow faster and spread more easily than HER2-negative tumors.

Importantly, testing identifies patients who could benefit from treatment that targets HER2, such as trastuzumab (Herceptin®) and lapatinib. These therapies can substantially improve survival in individuals with HER2-positive invasive breast cancer.

"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…This guideline update strengthens and clarifies recommendations for HER2 testing based on new evidence," says Antonio C. Wolff, MD, FACP, FASCO, co-chair of the ASCO/CAP HER2 Testing in Breast Cancer Panel and professor of oncology at the Johns Hopkins Kimmel Comprehensive Cancer Center.

One of the guideline's key recommendations is that everyone with invasive breast cancer should be tested to determine their HER2 status. While this is already being done during the care of most patients with invasive breast cancer, this guideline formalizes the recommendation and offers guidance aimed at improving the accuracy of HER2 testing. It provides detailed recommendations, for example, on how to test for HER2 and interpret the results. It also includes key points for health care providers and patients to discuss about HER2. This includes the reasons for the testing, the types of tests used, interpretation of test results, and the potential need for retesting if the cancer recurs.

The ASCO-CAP guideline aims to encourage breast cancer patients to take an active role in their care and aid in discussions with their health care providers. The organizations have also published a patient guide on HER2 testing that includes questions patients may want to ask their doctors.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

Wolff A, et al. Recommendations for Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Update. Journal of Clinical Oncology, Vol 31, No. 31 (November 1), 2013: Pp. 3997-4013. Available online at through Accessed October 15, 2013.

© 2005-2013 American Society of Clinical Oncology (ASCO) Patient Guide on HER2 testing. Available online at through Accessed October 15, 2013.

Menard S, et al. Role of HER2 gene overexpression in breast carcinoma. J Cell Physiol. 2000 Feb; 182(2):150-62. Available online at through Accessed October 15, 2013.

(October 7, 2103) ASCO and the CAP Release Updated Guideline on HER2 Testing in Breast Cancer. ASCO press release. Available online at through Accessed October 15, 2013.