New HER2 Testing Evidence Can Aid in Treatment Decision-Making for Upper GI Cancers

Two studies provide new evidence on HER2 testing to help in treatment decision-making—specifically, that local testing generally agrees with central laboratory testing in patients with gastric cancer or gastroesophageal junction adenocarcinoma (Abstract 434), and that loss of HER2 overexpression upon repeated biopsies is relatively common, suggesting that subsequent testing in certain patients may be warranted (Abstract 436).