[Synchronous bilateral breast cancer: risk factors, diagnosis, histology and treatment]

Synchronous bilateral breast carcinoma (SBBC) is not uncommon. Women with unilateral breast carcinoma are at increased risk for developing contralateral disease. The purpose of this study was to evaluate risk factors, diagnostic circumstances, histological characteristics and therapeutic methods for SBBC.

Between July 1992 and May 2006, 62 patients with SBBC were treated at Tenon hospital (Paris, France). Population was divided into two sub-groups corresponding with two successive periods. Epidemiological characteristics, diagnostic circumstances, therapeutic methods and histological characteristics were analysed.

Global incidence of SBBC during this period was 2.6%. The patients presenting a CSBS had a family antecedent of breast cancer in 23.7% of the cases. The most frequent situation associated a palpable tumour and an infraclinic contralateral lesion (43.5%). MRI made diagnosis possible in seven tumours. Among the patients 38.7% had a bilateral mastectomy and 33.9% profited from the technique of the ganglion sentinel. The proportions of invasive lobular carcinomas and the multifocal tumours were 17.7%. The tumours had the same histological type in 78.3% of the cases and the expression of oestrogen receptors was identical in 91.4% of the cases.

The principal risk factors of CSBS are a family history of breast cancer, the histological type lobular invasive and the multifocal character of the first tumour. A conservative surgery is possible as well as the use of the technique of the ganglion sentinel. The CSBS have histological similarities, probably due to environmental factors.