Chemotherapy use increased for: tumors with size 11-30 mm (OR = 2.72) or > 30 mm (OR: 2.65), ductal carcinoma (OR = 2.10), tumors with LVI (OR = 2.16), SBR grade 2 (OR = 3.05) or grade 3 (OR = 25.95), HER2+ (OR = 3.12), SN macro-metastases (OR = 3.70), and for women age between 41 and 75 years old (OR = 13.9) or < =40 years (OR = 75.8) (Table 4). This evidence concerns the gene ERBB2 and breast ductal adenocarcinoma.