The median (IQR) time from diagnosis of MBC to first radiotherapy treatment for BRM was 16.8 (7.1-34.7) months in HR-positive/ERBB2-negative cancer, 19.8 (12.2-35.1) months in ERBB2-positive/HR-positive cancer, 15.0 (7.1-30.1) months in ERBB2-positive/HR-negative cancer, 7.5 (2.3-17.4) months in TNBC, and 14.1 (3.0-30.1) months in unknown subtypes (Table 2). Here, ERBB2 is linked to cancer.