title: Irradiation effect after mastectomy on breast cancer recurrence in patients presenting with locally advanced disease.
abstract: BACKGROUND
  Current guidelines recommend postmastectomy irradiation (PMI) for patients with tumors >5 cm and/or ≥4 positive lymph nodes. This study evaluates the effect of PMI on recurrence and survival within tumor size and node status groups.
  
  
  METHODS
  Locoregional and distant recurrences and survival for different tumor and treatment characteristics were analyzed in 2,797 patients with invasive breast cancer treated with mastectomy.
  
  
  RESULTS
  Tumor size, positive nodes, extranodal extension, lymphatic/vascular invasion, estrogen receptor/progesterone negative, HER-2 positive, and high grade were associated with significantly increased recurrence. In patients with ≥4 positive nodes and patients with tumors >5 cm and positive nodes, PMI decreased local and distant recurrence (overall 53% vs 24%, P < .001) and increased disease-free survival (P < .001) but not overall survival. In patients with less disease, a benefit from PMI irradiation could not be identified.
  
  
  CONCLUSIONS
  PMI is indicated for patients with ≥4 positive nodes or patients with tumors >5 cm and positive nodes.
authors.affiliation: Department of Surgery, Swedish Cancer Institute, Swedish Medical Center, Seattle, WA 98104, USA.
authors.forename: Angie R
authors.initials: AR
authors.lastname: Taras
authors.forename: Jason D
authors.initials: JD
authors.lastname: Thorpe
authors.forename: Astrid D
authors.initials: AD
authors.lastname: Morris
authors.forename: Mary
authors.initials: M
authors.lastname: Atwood
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Lowe
authors.forename: J David
authors.initials: JD
authors.lastname: Beatty
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis / Q000532:radiotherapy / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000532:radiotherapy*; D009367:Neoplasm Staging; D011184:Postoperative Period; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome