Breast cancer arising within fibroadenoma: collective analysis of case reports in the literature and hints on treatment policy

BACKGROUND: Breast cancer arising within a fibroadenoma (BcaFad) is rare; the rate varies from 0.002% to 0.125% in fibroadenoma specimens. Owing to its rarity, the clinicopathologic feature and treatment principle of BcaFad is still not clear. Therefore, the aim of this study was to perform a collective analysis of case reports in the literature to identify the characteristics and optimal treatment for BcaFad. METHODS: We analyzed an aggregated sample of 30 patients with BcaFad from case reports in the literature (n =24 cases) and our present study (n =6 cases). We collected and analyzed the clinicopathologic features and prognoses of patients with BcaFad, as well as treatments they received. RESULTS: The patients’ mean age at diagnosis was 46.9 years. Twenty BcaFad patients (66.7%) received breast-conserving surgery (BCS), and nine other patients (30.0%) were treated with mastectomy. The rate of lymph node metastasis in BcaFad patients was 23.8%. The breakdown of the histological types of BcaFad was invasive ductal carcinoma (53.3%), followed by ductal carcinoma in situ (23.3%), lobular carcinoma in situ (16.7%) and invasive lobular carcinoma (13.3%). More than half of patients with positive hormone receptor status received hormone therapy. Most BcaFad patients with lymph node metastases received chemotherapy, and 20.0% of BcaFad patients treated with BCS received further radiotherapy. Only one patient had recurrence after surgery, and another had lung metastasis when diagnosed with BcaFad. CONCLUSIONS: Most BcaFad patients could be managed by BCS. Adjuvant radiotherapy could be performed, but was not mandatory. Chemotherapy should be considered as a treatment option in the presence of lymph node metastasis.