Multiple versus unifocal breast cancer: clinicopathological and immunohistochemical differences

Multiple breast cancer (MBC) is a controversial topic due to the lack of a consensus regarding its definition, classification issues and imprecise management recommendations in current reference guidelines. In four years, 756 patients with breast cancer (BC) were surgically treated in our Unit, 91 (12.03%) of them being pathologically diagnosed as MBCs. We present the results of our retrospective case-control study that performed a comparison between the clinicopathological characteristics and immunohistochemical (IHC) profiles of our MBC group versus a control group, represented by a sample of 184 cases randomly chosen from those with unifocal breast cancer (UBC). Starting from the premise of increased biological aggressivity of MBC, showed by several reports, we proposed to research the possible differences between these groups and to highlight their potential predictive and/or prognostic value. We found that MBC patients have a poorer prognosis than UBC ones - younger age at diagnosis [more cases less than 50 years old (p=0.03)], a lower frequency of T1 and a higher rate of T3 tumors [when using aggregate tumor size measuring method (p