Test for HER2 in gastroesophageal adenocarcinoma: guidelines

Last Updated: 2016-11-17

By Will Boggs MD

NEW YORK (Reuters Health) - Patients with gastroesophageal adenocarcinoma (GEA) should be tested for HER2 status and be offered HER2-targeted therapy when positive, according to new guidelines.

"These guidelines are unique and are based on HER2 biology in gastric/esophageal adenocarcinoma and distinguish it from HER2 biology in breast cancer," Dr. Jaffer A. Ajani from MD Anderson Cancer Center in Houston, Texas, told Reuters Health by email. "This may be one of the major accomplishments of the guidelines."

HER2 amplification and/or overexpression is present in up to 38% of gastroesophageal adenocarcinomas, which will affect up to 43,280 individuals in the U.S. this year, according to Dr. Ajani and colleagues from the College of American Pathologists, the American Society for Clinical Pathology and the American Society of Clinical Oncology.

The team systematically reviewed 116 published articles in order to develop evidence-based guidelines for HER2 testing in GEA.

While a comparable guideline exists for assessment of HER2 in breast cancer, guidelines specific for GEA were needed because the pattern of HER2 protein overexpression and/or gene amplification in GEA is distinctly different, they note.

The new recommendations for clinicians and pathologists appeared online November 14 in the Journal of Clinical Oncology.

Patients with advanced GEA who are potential candidates for HER2-targeted therapy should have their tumor tissue tested for HER2 status, preferably before initiating trastuzumab therapy, the guideline says. Those with HER2-positive tumors should be offered combination chemotherapy and HER2-targeted therapy as the initial treatment.

The recommendations for pathologists address strategies that can help ensure optimal performance, interpretation, and reporting of established assays in patients with GEA.

"The comprehensive guidelines encompass many details needed to guide the pathologist on sample selection, sample processing, standardization of the laboratories, scoring methods, interpretation, reporting, and finally some guidance to clinicians," Dr. Ajani said.

Coauthor Dr. Angela N. Bartley from St. Joseph Mercy Hospital in Ann Arbor, Michigan, said, "The data and recommendations in the guideline will show that pathologists and clinicians (including oncologists, surgeons, and generalists) must work together to ensure the best outcomes for patients with GEA."

"This begins with communication between the gastroenterologists, surgeons, and pathologists to ensure adequate neoplastic tissue in biopsy and surgical specimens, subsequent proper tissue fixation, validation and quality assurance of the testing methodology, and prompt and clear result reporting so that oncologists may make the best treatment decisions for their patients," she told Reuters health by email.

The authors note, "as the fields of genomics, proteomics, and biotechnology continue to evolve, novel and more accurate methods of assessing HER2 status may become available. Similarly, as more clinical trials are conducted on HER2-directed therapy in GEA, changes in treatment algorithms may necessitate updates to these recommendations in the future."

SOURCE: http://bit.ly/2fVTRBq

J Clin Oncol 2016.