Comparison of the histopathology and prognosis of bilateral versus unilateral multifocal multicentric breast cancers

Multiple breast cancers may present with different clinical and biological characteristics. The data indicate that multifocal (MF), multicentric (MC), and bilateral synchronous (BS) breast cancers (BC) are more aggressive and have an equivalent or moderately poorer survival rate compared with unilateral cases. However, a comparison of these multiple breast cancers has not been covered in the literature. The aim of this study was to describe the histopathological characteristics of patients suffering from MF, MC, and BS breast carcinoma and to compare their prognoses. Retrospective data for MF, MC, and BS breast carcinoma patients treated in five different breast cancer units in Turkey between 2003 and 2012 were collected. MF and MC cancers were defined as more than one lesion in the same quadrant or in separate quadrants, respectively. There were 507 patients (271 MF, 147 MC, and 89 BS) treated in this time period. BS breast carcinoma patients were younger than the other groups (44.83 ± 9.6, 47.27 ± 11.6, and 51.11 ± 11.8 years for BS, MF, and MC breast carcinoma patients, respectively). MFBC and MCBC patients in this study were younger than the ages reported in Western literature, but this result was similar to the ages reported in Eastern literature. The five-year survival rates and recurrence rates were not statistically different among groups (P = 0.996 and P = 0.263, respectively). According to univariate analyses, tumor size, histological grade, and lymph node status were statistically significant factors that affected survival. However, only lymph node involvement was significant for survival according to multivariate analyses. The clinical significance of MF, MC, and BS breast cancers is still unclear and their influence on prognosis is controversial. Disease-free and overall survival rates of BS breast cancers might be similar to MF and MC breast cancers.