The majority of women at all ages were treated with anthracycline-based adjuvant chemotherapy and there was no difference in the choice of immediate surgical management between either age groups or between genetic risk groups.
Significantly more women in the ≤35 years age group had grade 3 (P < 0.01) and ER-negative (P < 0.02) tumours compared with women diagnosed in the older age group (>35 but ≤40 years). There was no significant difference in tumour size or lymph node status based on age categories. Compared with women with no family history, women falling into the 10% of the cohort estimated from family history to be most likely to carry BRCA1 or BRCA2 gene mutations, high genetic risk women had significantly more grade 3 tumours (P < 0.001) and a nonsignificant trend towards more ER-negative tumours.