Abstract 105P
Background
Multiple breast cancer (MBC) consists of two large groups – multifocal BC (MFBC) and multicentric BC (MCBC). Cases with MBC are relatively less studied compared to the ones with unifocal breast cancer (UBC) in Bulgaria regarding precise staging, different surgical approaches, treatment options and prognosis due to the lack of universal definition separating MFBC from MCBC. The goal of the study was to evaluate the prognostic value of the number of cancer foci for overall survival (OS) and local recurrence-free survival (LFS) in patients with MBC and UBC in Bulgaria.
Methods
Six hundred and eighty-five females with histologically and immunohistochemically verified BC, diagnosed and treated for a period of ten years (March 2009 – March 2019) at the Breast Unit of University Hospital “Queen Joanna – ISUL”, Medical University – Sofia, Bulgaria were retrospectively analyzed. For the aim of the investigation the cohort of 685 patients were divided in two main groups according to the number of tumor foci – first group of patients diagnosed with UBC (n=513, 74,9%) and second one with MBC (n=172, 25,1%). The last one was further classified into 3 subgroups: women with 2 to 3, 4 to 6 and 6 to 8 multiple cancers in the same breast.
Results
The largest subgroup included patients with 2 to 3 tumors (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 established differences in OS even though with no significant value, p=0,570. Statistical analysis of LFS between patients with different numbers of synchronous cancer foci reports significant difference – p=0,041.
Conclusions
The peculiarity of MBC as a pathology sets a series of unsettled problems in diagnostic and therapeutic aspects on a large scale. Unacquainted additional tumors during medical imaging diagnosis led to incorrectly defining the disease as unifocal. The reasons behind these diagnostic gaps could be found in imperfection of the chosen imaging modality and lack of knowledge regarding MBC.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.