Inclusion Criteria:  New invasive estrogen and/or progesterone receptor-positive (ER+ and/or PR+), HER2-negative (HER2-) invasive breast carcinoma diagnosis as per ASCO-CAP guidelines The primary tumour characteristics are either: Grade 1 and ≤5 cm on microscope exam, OR Grade 2 and ≤3 cm on microscope exam, OR Grade 3 and ≤1 cm on microscope exam Treated with standard loco-regional therapy: breast conserving surgery followed by adjuvant radiotherapy OR total mastectomy Axillary lymph node-negative (N0) Able to provide oral consent and complete questionnaires in French or English as per study protocol  Exclusion Criteria:  Metastatic cancer