Background: Incidence of primary bilateral breast cancer (BC) is rare and does not exceed 5%. BRCA1/2 mutation carriers diagnosed with breast cancer have a strong life time risk of developing contralateral breast cancer (53% versus 2%).
Patients and methods: A group of 108 patients with bilateral breast cancer, who reported at our Cancer Centres from 2000 to 2002, were subjected to genetic testing. Similarities and differences between BRCA1/2 carriers and non-carriers were analysed in terms of family history, pathology of tumour, age of diagnosis, developing contralateral BC and second primary cancer.
Results: BRCA1/2 mutations were detected in 32 of 108 patients. Family history of BC was identified in 46.9% of these patients compared with 22.4% of non-carriers (P <0.05). Synchronous BC was diagnosed significantly rarer [4 of 32 (12.5%)] in BRCA1/2 carriers than in the non-carrier group [26 of 76 (34.2%)]. In addition, patients with BRCA mutations were younger when they were diagnosed than non-carriers. BRCA1/2 carriers had a significantly higher incidence of medullary BC (13.6% versus 1.7%) and developed ovarian cancer significantly more frequently than non-carriers (12 of 32 and 1 of 72 patients, respectively).
Conclusions: Patients with bilateral BC having BRCA mutations are significantly younger than non-carriers. They also have a significantly higher family history of BC and an increased risk of developing ovarian cancer. The differences in clinical aspects of BRCA carriers with bilateral BC should be considered in clinical management.