title: Identification of Risk Factors for Locoregional Recurrence in Breast Cancer Patients with Nodal Stage N0 and N1: Who Could Benefit from Post-Mastectomy Radiotherapy?
abstract: BACKGROUND
  The locoregional recurrence (LRR) rate was reported as high as approximately 20% in stage I-II breast cancer following mastectomy. To investigate the risk factors for LRR in pT1-2N0-1 breast cancer patients treated with mastectomy but not radiation, and to define a subgroup of patients at high risk of LRR who may benefit from postmastectomy radiotherapy (PMRT).
  
  
  METHODS
  In total, 390 patients with pT1-2N0M0 (n = 307) and pT1-2N1M0 (n = 83) breast cancer who underwent total mastectomy without adjuvant radiotherapy from 2002 to 2011 were enrolled in the study.
  
  
  RESULTS
  After a median follow-up period of 5.6 years (range, 0.6-11.3 years), 21 patients had 18 systemic relapses and 12 LRRs including six in the chest wall and eight in the regional nodal area. The 5-year LRR-free survival (LRRFS) rates were 97.0% in pN0, 98.8% in pN1, and 97.4% in all patients. Multivariate analysis revealed that age < 50 years (Hazard Ratio, 11.4; p = 0.01) and no adjuvant chemotherapy (Hazard Ratio, 10.2; p = 0.04) were independent risk factors for LRR in pN0 patients. Using these factors, the 5-year LRRFS rates were 100% without any risk factors, 96.4% with one risk factor, and 86.7% with two risk factors. In pN1 patients, multivariate analysis revealed that having a hormone receptor negative tumor (Hazard Ratio, 18.3; p = 0.03) was the only independent risk factor for LRR. The 5-year LRRFS rates were 100.0% for luminal type, and 92.3% for non-luminal type cancer.
  
  
  CONCLUSIONS
  Patients with pT1-2N0-1 breast cancer who underwent total mastectomy without PMRT could be stratified by nodal stage and risk factors for LRR. PMRT may have of value for node negative patients aged less than 50 years and who are not treated with adjuvant chemotherapy, and for non-luminal type patients with one to three positive nodes.
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.|Department of Radiation Oncology, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Eunjin
authors.initials: E
authors.lastname: Jwa
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.|Departments of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyung Hwan
authors.initials: KH
authors.lastname: Shin
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
authors.forename: Hyeon Woo
authors.initials: HW
authors.lastname: Lim
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Jung
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
authors.forename: Seeyoun
authors.initials: S
authors.lastname: Lee
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
authors.forename: Han-Sung
authors.initials: HS
authors.lastname: Kang
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
authors.forename: EunSook
authors.initials: E
authors.lastname: Lee
authors.affiliation: Center for Breast Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.|Department of Radiation Oncology, Soonchunhyang University College of Medicine, Seoul, Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis