Should HER2 Testing Be Routinely Performed in Patients with Gastric Cancer?
The short answer is yes! New evidence-based guidelines for human epidermal growth factor receptor 2 (HER2) testing in advanced gastric and gastroesophageal adenocarcinoma (GEA) have been released jointly by the College of American Pathologists (CAP), American Society for Clinical Pathology (ASCP), and American Society of Clinical Oncology (ASCO).
Currently, HER2 is the only marker that can be used to guide treatment choices in advanced GEA. Testing for HER2 may help identify individual patients who could benefit from targeted therapy with the anti-HER2 monoclonal antibody Herceptin®, (trastuzumab). Research suggests that adjunctive therapy with Herceptin may increase overall survival in advanced GEA compared with chemotherapy alone.1
Herceptin is a targeted therapy that has made important contributions to improved outcomes among women with HER2-positive breast cancer. HER2 is also overexpressed in some stomach cancers. The HER2 pathway is a biological pathway involved in cellular replication and growth. Herceptin targets and blocks the HER2-protein and is used for the treatment of both early-stage and more-advanced HER2-positive cancers.
The guidelines were published online November 14 in the Archives of Pathology & Laboratory Medicine, American Journal of Clinical Pathology, and Journal of Clinical Oncology.2
A key point about the new guidelines is that they recommend HER2 testing during the initial diagnosis of advanced GEA and at important other points during treatment. The guidelines point out that the evidence does not support HER2 testing in patients with resectable tumors. They acknowledge that not all patients with advanced GEA may be candidates for anti-HER2 therapy, and advise that HER2 testing not be required in such patients. When the HER2 status is unclear because of technical issues, such as inadequate tissue sampling, additional tumor sampling may be pursued if it can be done safely.
- Bang Y-J, Van Cutsem E, Feyereislova A et al.. Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomised controlled trial. Lancet. 2010; 376:687-697.
- Bartley A, Washington M, Colasacco C, et al. HER2 Testing and Clinical Decision Making in Gastroesophageal Adenocarcinoma: Guideline From the College of American Pathologists, American Society for Clinical Pathology, and the American Society of Clinical Oncology. DOI: 10.1200/JCO.2016.69.4836 Journal of Clinical Oncology– published online before print November 14, 2016
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