title: Timing of breast cancer surgery, menstrual phase, and prognosis: Systematic review and meta-analysis.
abstract: BACKGROUND
  For over 25 years, there has been a debate revolving around the timing of breast cancer surgery, menstrual cycle, and prognosis.
  
  
  METHODS
  This systematic review synthesizes and evaluates the body of evidence in an effort to inform evidence-based practice. A keyword and reference search was performed in PubMed and Web of Science to identify human studies that met the inclusion criteria. A total of 58 studies (48 international and 10 U.S.-based) were identified. We provided a narrative summary on study findings and conducted a meta-analysis on a subset of studies where quantitative information was available.
  
  
  RESULTS
  Findings from both qualitative and quantitative analyses were inconclusive regarding performing breast cancer surgery around a specific phase of the menstrual cycle.
  
  
  CONCLUSIONS
  Based on the Institute of Medicine criteria, evidence is insufficient to recommend a change in current primary breast cancer surgery practice based on menstrual phase.
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States. Electronic address: klonoffc@illinois.edu.
authors.forename: Hillary
authors.initials: H
authors.lastname: Klonoff-Cohen
authors.affiliation: Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois at Urbana-Champaign, United States.
authors.forename: Ruopeng
authors.initials: R
authors.lastname: An
authors.affiliation: California Emerging Infections Program, United States.
authors.forename: Theodora
authors.initials: T
authors.lastname: Fries
authors.affiliation: Department of Kinesiology and Community Health University of Illinois at Urbana-Champaign, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Le
authors.affiliation: Department of Psychology, San Diego State University, United States.
authors.forename: Georg E
authors.initials: GE
authors.lastname: Matt
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008408:Mastectomy; D008597:Menstrual Cycle; D011379:Prognosis
keywords: Breast cancer; Luteal phase; Menstrual cycle; Premenopausal; Surgery