Analysis of the Prognostic Role of the Number of Cancer Foci in Bulgarian Patients with Multiple Breast Cancer

Ipsilateral synchronous primary multiple breast cancer (MBC) is a relatively unknown subject compared to unifocal breast cancer (UBC) and includes the group of multifocal (MFBCs) and multicentric BC (MCBC). The aim of our research is to evaluate the prognostic value of the number of cancer lesions for overall survival (OS) and local recurrence-free survival (LFS) in Bulgarian patients with MBC and UBC. A retrospective study was conducted over 685 Bulgarian women with BC, diagnosed and treated for a period of ten years (March 2009 – March 2019) at the Department of Surgery, University Hospital “Tsaritsa Yoanna – ISUL”, Medical University of Sofia. The results from dividing the patients into two main groups according to the number of primary lesions showed that cases diagnosed with UBC were 513 (74.9%) and the ones with MBC – 172 (25.1%). The largest subgroup included females with 2 to 3 tumours (n=134, 78%), followed by cases with 4 to 6 lesions (n=35, 20.3%) and women with 6 to 8 foci (n=3, 1.7%). The statistical analysis of OS showed significant difference between the two main groups UBC and MBC, p=0.003. When comparing the subgroups of patients with MBC according to the absolute number of multiple foci we also established differences in OS even though with no significant value, p=0.570. Statistical analysis of LFS among patients with different number of synchronous cancer foci reports significant difference – p=0.041. MBC unites various lesions with different clinical manifestation, histopathological characteristics and more aggressive prognosis in comparison with UBC.