Percentage of patients diagnosed with gastroesophageal adenocarcinoma (GEA) cancer (primary or metastatic) for which biopsies, resection, or metastatic specimens have HER2 evaluation conducted using the current ASCO/CAP recommended manual system or computer-assisted system consistent with the optimal algorithm. INSTRUCTIONS: This measure should be submitted when quantitative HER2 evaluation is conducted during the performance period for patients with gastroesophageal adenocarcinoma. This measure may be submitted by eligible clinicians who perform the quality actions described in the measure based on the services provided and the measure-specific denominator coding. This measure has two performance rates that contribute to the overall performance score: 1. Percentage of all pathology reports for GEA cancer biopsies or resection specimens (primary or metastasis) for patients with known GEA that have HER2 immunohistochemistry (IHC) evaluation conducted using the current ASCO/CAP recommended optimal scoring algorithm completed. 2. Percentage of pathology reports GEA cancer patients with equivocal (IHC 2+) human epidermal growth factor receptor 2 (HER2) testing result that had a follow-up HER2 evaluation completed using in-situ hybridization (ISH). The overall performance score is a weighted average of: (Numerator 1 + Numerator 2)/(Denominator 1 + Denominator 2).