In monarchE, among patients with HR+, HER2- invasive EBC, high risk of recurrence was defined as having either ≥4 positive axillary lymph nodes (ALNs), or 1–3 positive ALNs in combination with ≥1 of the following high-risk features: primary invasive tumor size ≥5 cm, histological Grade 3 tumor, or tumor with central Ki-67 index ≥20% [19, 20]. Here, ERBB2 is linked to neoplasm.