ERBB2 and neoplasm: Pre-surgical tumor size (21–50 mm, >50 mm, or attached to chest wall vs. <20 mm), nodal stage (N1, N2, or N3 vs. N0), and proxy subtype (luminal B [HER2-negative], luminal B [HER2-positive], HER2-enriched or basal vs. luminal A), were associated with compliance with recommended chemotherapy (OR <1.00 and P < 0.001 for all comparison).