Incidence and prognostic impact of HER2-positivity loss after dual HER2-directed neoadjuvant therapy for HER2-positive breast cancer

Loss of HER2-positivity can occur in patients with residual disease after neoadjuvant treatment. A retrospective trial at Cedars-Sinai Medical Center (Los Angeles, CA) investigated the incidence and prognostic impact of HER2-positivity loss after neoadjuvant dual HER-targeted therapy plus chemotherapy for HER2-positive breast cancer. The study showed that almost half of patients with residual disease lost HER2-positivity. The majority (88%) of these patients were classified as HER2-low. The loss of HER2-positivity may not confer negative prognostic impact, although the follow-up time was short.