Breast cancer in women ≤35 years:: Review of 1002 cases from a single institution

Background: Early-onset breast cancer may differ with respect to etiology, clinical features and outcome compared with breast cancer in older women. To gain further insight, we retrospectively reviewed the clinical features and outcome of women less than or equal to 35 years with primary breast cancer seen at our institution over a 30-year period. Patients and methods: Charts were reviewed for women with operable breast cancer diagnosed less than or equal to 35 years of age seen at the Princess Margaret Hospital (PMH), Toronto from 1965-1994. Results: One thousand eighty-six women with non-metastatic invasive breast cancer, aged 18.3-35.6 years (median 32.1 years) were referred to PMH. Symptoms at presentation included: self-detected breast lump (83%), other breast symptom (10%), physician diagnosis (4%) and unknown (3%). Tumor size was known in 936 (>2 cm in 61%) and nodal status in 888 (lymph node positive in 52%). Modified radical mastectomy was performed in 568 (57%) and breast-conservation surgery (BCS) in 422 (42%). Five hundred sixteen (51%) patients received adjuvant radiotherapy and five hundred thirty-four (53%) adjuvant systemic therapy. Two hundred ninety-three (29%) patients had a family history of breast cancer (FH). Contralateral breast cancer (CBC) occurred more frequently in women with FH (P range 0.042-0.008). Local recurrence (LR) was 37% and 73% at 10 years in those treated by BCS with and without radiotherapy, respectively. At 10 years, disease-free survival (DFS) was 30% and overall patient survival 48%. Conclusions: In this cohort, breast cancer was usually self-diagnosed and tumors were >2 cm at presentation in approximately two-thirds of cases, suggesting the possibilities of a delay in diagnosis, more aggressive tumors or both. Our results are compatible with the known association of breast cancer FH with increased CBC. Our data also corroborates the suggestion that positive genetic testing in this age group should lead to consideration of more aggressive ipsilateral and contralateral breast management. In those receiving adjuvant irradiation after BCS, the LR rate was high, but did not impact on overall survival.