title: Neoadjuvant Chemotherapy for Breast Cancer, Is Practice Changing? A Population-Based Review of Current Surgical Trends.
abstract: BACKGROUND
  Neoadjuvant chemotherapy in breast cancer is used to downstage locally advanced and inoperable tumors. Expanded benefits of neoadjuvant chemotherapy include downstaging of tumors to allow breast-conserving surgery (BCS) and assessment of in vivo tumor response. We sought to identify patterns and predictors of neoadjuvant chemotherapy use to determine if this has translated into population-level clinical practice.
  
  
  METHODS
  All patients undergoing surgery for invasive breast cancer between January 2012 and June 2014 were identified from our provincial synoptic operating room database. Data regarding patient demographics, hospital, operating surgeon, preoperative tumor characteristics, neoadjuvant treatment, and type of surgery performed were collected. Descriptive statistics and multivariable analysis were used to identify predictors of neoadjuvant chemotherapy.
  
  
  RESULTS
  A total of 4186 patients were identified, 363 (8.53%) of whom underwent neoadjuvant chemotherapy. A significant increase was seen in the use of neoadjuvant chemotherapy over time. In multivariable analysis, neoadjuvant chemotherapy was associated with prechemotherapy tumor size, multicentricity, lymph node positivity, and decreasing patient age. In addition, there was significant variability in neoadjuvant chemotherapy use between operating surgeons. Of those patients who underwent neoadjuvant chemotherapy, 68.9% were not pretreatment candidates for BCS. At the time of definitive surgery, 72.1% had mastectomy, with 18.7% opting for contralateral prophylactic mastectomy. As reported, this was due to the tumor being advanced/too large (50.4%), patient preference (12.6%), multicentricity (8.8%) and margins, genetics, and previous radiotherapy (4%).
  
  
  CONCLUSIONS
  A significant increase in the use of neoadjuvant chemotherapy over time was identified, and treatment with mastectomy as definitive surgical management remained high. There was significant variability in neoadjuvant chemotherapy use by the operating surgeons, in addition to factors generally associated with more locally advanced/aggressive tumors.
authors.affiliation: Department of Surgical Oncology, University of Calgary, 1331 29 Street Northwest, Calgary, AB, T2N 4N2, Canada, peter.graham@albertahealthservices.ca.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Graham
authors.forename: Mantaj S
authors.initials: MS
authors.lastname: Brar
authors.forename: Tianne
authors.initials: T
authors.lastname: Foster
authors.forename: Mike
authors.initials: M
authors.lastname: McCall
authors.forename: Antoine
authors.initials: A
authors.lastname: Bouchard-Fortier
authors.forename: Walley
authors.initials: W
authors.lastname: Temple
authors.forename: May Lynn
authors.initials: ML
authors.lastname: Quan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D055815:Young Adult
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human