title: Pathological Characteristics of Both Tumors in Bifocal and Bicentric Breast Cancer.
abstract: OBJECTIVE
  The objective of the present study was to describe the biological characteristics of each lesion in patients with bifocal/bicentric (BF/BC) breast cancer.
  
  
  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.
  
  
  CONCLUSIONS
  Immunohistochemistry should be performed only on the main tumor in cases of BF/BC cancer.
authors.affiliation: Department of Surgical Oncology, René Huguenin Center, St Cloud, France.
authors.forename: Rabab
authors.initials: R
authors.lastname: Mosbah
authors.affiliation: Department of Surgical Oncology, René Huguenin Center, St Cloud, France Equipe d'Accueil 7285, Risk and Safety in Clinical Medicine for Women and Perinatal Health, University Versailles-Saint-Quentin, Montigny-le-Bretonneux, France.
authors.forename: Roman
authors.initials: R
authors.lastname: Rouzier
authors.affiliation: Department of Pathology, René Huguenin Center, St Cloud, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Guinebretière
authors.affiliation: Department of Biostatistics, Curie Institute, Paris, France.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Falcou
authors.affiliation: Public Health Curie Institute, René Huguenin Center, St Cloud, France.
authors.forename: Denise
authors.initials: D
authors.lastname: Stevens
authors.affiliation: Department of Surgical Oncology, René Huguenin Center, St Cloud, France Equipe d'Accueil 7285, Risk and Safety in Clinical Medicine for Women and Perinatal Health, University Versailles-Saint-Quentin, Montigny-le-Bretonneux, France delphine.hequet@gmail.com.
authors.forename: Delphine
authors.initials: D
authors.lastname: Héquet
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D019394:Ki-67 Antigen; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: Multifocality; breast cancer; multicentricity