title: Comparison of outcomes of breast conserving therapy in multifocal and unifocal invasive breast cancer.
abstract: BACKGROUND
  There is controversy about whether breast conserving therapy (BCT) should be contraindicated in multifocal (MF) breast cancer. Few studies have reported on the oncologic safety of BCT in MF breast cancer.
  
  
  METHODS
  We reviewed a prospective database of 1,169 women with invasive breast cancer who were treated with segmentectomy and whole breast irradiation from 1991 through 2009 and followed at our institution. Multifocal breast cancer was defined as 2 or more distinct tumors excised with a single incision or segmentectomy. We compared 2 groups, MF and unifocal breast cancer patients, with respect to demographics, tumor characteristics, adjuvant systemic therapy, local recurrence (LR), disease-free survival (DFS), and overall survival (OS).
  
  
  RESULTS
  One hundred sixty-four patients with MF and 999 with unifocal invasive breast cancer were treated with BCT. Median follow-up was 112 months. Compared with the unifocal group, patients in the MF group had higher 10-year LR (0.6% vs 6.1%, p < 0.001) and lower 10-year DFS (97.7% vs 89.3%, p < 0.001) and OS (98.4% vs 85.8%, p < 0.001). On multivariable analysis, multifocality was independently significantly associated with local recurrence-free survival (LRFS), DFS, and OS.
  
  
  CONCLUSIONS
  Our data suggest that BCT in MF breast cancer is oncologically safe but may result in a slightly inferior outcome compared with BCT in unifocal breast cancer.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. alice.chung@cshs.org
authors.forename: Alice P
authors.initials: AP
authors.lastname: Chung
authors.forename: Kelly
authors.initials: K
authors.lastname: Huynh
authors.forename: Travis
authors.initials: T
authors.lastname: Kidner
authors.forename: Parisa
authors.initials: P
authors.lastname: Mirzadehgan
authors.forename: Myung-Shin
authors.initials: MS
authors.lastname: Sim
authors.forename: Armando E
authors.initials: AE
authors.lastname: Giuliano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D016896:Treatment Outcome