Pathological Characteristics of Both Tumors in Bifocal and Bicentric Breast Cancer.

ABSTRACT

AIM: The objective of the present study was to describe the biological characteristics of each lesion in patients with bifocal/bicentric (BF/BC) breast cancer. PATIENTS AND METHODS: We retrospectively reviewed the charts of 205 patients diagnosed with BF/BC cancer. The degree of concordance between the two lesions was assessed using Pearson product-moment correlation coefficients. RESULTS: A total of 205 patients were included. Both tumors displayed the same histological type in 182 patients (89%). The same grade was found for both tumors in 178 of the cases (96.7% and 100% for grade 3 lesions). Immunohistochemical concordance between the two tumors was excellent, with correlation coefficients of 0.98, 0.96 and 0.99 for estrogen receptors (ER), progesterone receptors (PR) and Ki67, respectively. Human Epidermal growth factor Receptor 2 (HER2) status was available for both tumors in 177 cases (86%), with a perfect concordance. We did not find any differences in molecular sub-type between tumor foci. CONCLUSION: Immunohistochemistry should be performed only on the main tumor in cases of BF/BC cancer.