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An evidence-based clinical practice guideline on human epidermal growth factor receptor 2 (HER2) testing for patients with gastroesophageal cancers was recently released by ASCO, the College of American Pathologists (CAP), and the American Society for Clinical Pathology (ASCP). "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" is now available as an early online release published in Archives of Pathology & Laboratory Medicine, American Journal of Clinical Pathology, and Journal of Clinical Oncology.


The guideline provides recommendations about appropriate HER2 testing for patients at key decision points throughout their cancer therapy to determine if they are eligible for targeted therapy. Patients eligible have additional treatment options available to them and they generally experience improved outcomes.


Certain patients with advanced gastric cancer will have more HER2, known as an overexpression of HER2, than other patients. For those patients, the targeted therapy trastuzumab has been shown to improve patient survival when it is added to standard chemotherapy.


"This guideline recommends that assessment of HER2 status be included in the diagnostic protocol for gastroesophageal adenocarcinoma," explained Angela N. Bartley, MD, FCAP, a pathologist at St. Joseph Mercy Health System, Ann Arbor, Mich. "Ultimately, clinicians who use the guideline will help ensure that patients receive the best treatment for their type of cancer."


Bartley represented CAP and was one of the three organizational co-chairs of the international panel of pathology and oncology experts who developed the guideline. The panel's evidence-based process included extensive review of relevant published literature, feedback on draft guidance garnered through an open comment period earlier this year, and revisions based on that open commentary.


"As cancer care evolves to be increasingly personalized, this new guideline helps establish standards for when and how to accurately perform HER2 testing to guide treatment for gastroesophageal adenocarcinoma patients," said co-chair Jaffer A. Ajani, MD, FASCO, a medical oncologist at the MD Anderson Cancer Center in Houston, who represented ASCO for this guideline.


This comprehensive, evidence-based guideline for HER2 testing in gastroesophageal adenocarcinoma (GEA) has a set of 11 recommendations that are separated to support those who treat the patient with cancer and those who perform tumor tissue testing. Some of the recommendations include the following:


* In patients with advanced GEA who are potential candidates for HER2 targeted therapy, the treating clinician should request HER2 testing on tumor tissue.


* Treating clinicians should offer combination chemotherapy and HER2-targeted therapy as the initial treatment for appropriate patients with HER2 positive tumors who have advanced GEA.


* Laboratories/pathologists must specify the antibodies and probes used for the test and ensure assays are appropriately validated for HER2 immunohistochemistry (IHC) and in situ hybridization (ISH) testing on GEA specimens.


* When GEA HER2 status is being evaluated, laboratories/pathologists should perform/order IHC testing first followed by ISH when IHC result is 2+ (equivocal). Positive (3+) or negative (0 or 1+) HER2 IHC results do not require further ISH testing.



"We encourage clinical teams around the world to adopt these guidelines," said Mary Kay Washington, MD, PhD, FASCP, a pathologist at Vanderbilt University Medical Center, Nashville, Tenn., who represented ASCP. "It will help improve patient care by ensuring that only patients likely to benefit from HER2-directed therapy are treated with trastuzumab."