Central Pathology Laboratory Review of HER2 and ER in Early Breast Cancer: An ALTTO Trial BIG 2-06 / NCCTG N063D (Alliance) Ring Study

摘要

Background/PurposeChoice of therapy for breast cancer relies on human epidermal growth factor receptor-2 (HER2) and estrogen receptor (ER) status. Before randomization in the phase III adjuvant ALTTO trial for HER2-positive disease, HER2 and ER were centrally reviewed by Mayo Clinic (Rochester, MN and Scottsdale, AZ) for North America and by the European Institute of Oncology (IEO; Milan, Italy) for rest of world (except China). Discordance rates (local vs. central review) differed between Mayo and IEO. Among locally HER2-positive cases, 5.8% (Mayo) and 14.5% (IEO) were centrally HER2-negative. Among locally ER-positive cases, 16.2% (Mayo) and 4.2% (IEO) were centrally ER-negative. Among locally ER-negative cases, 3.4% (Mayo) and 21.4% (IEO) were centrally ER-positive. We, therefore, performed a ring study to identify features contributing to these differing discordance rates.