title: Real-world outcomes of postmastectomy radiotherapy in breast cancer patients with 1-3 positive lymph nodes: a retrospective study.
abstract: OBJECTIVE
  To assess the treatment outcomes and to explore the determinants of clinical outcome in breast cancer patients with 1-3 positive nodes who did or did not receive postmastectomy radiotherapy (PMRT) in a tertiary care referral cancer center in Northern Thailand.
  
  
  METHODS
  We investigated a retrospective cohort of registered breast cancer patients at the Faculty of Medicine, Chiang Mai University, Thailand from 2001-2007. Analysis was performed using Cox regression models to identify factors affecting the overall survival (OS) and relapse-free survival (RFS) rates. Comparisons were made between two cohorts: women who received adjuvant PMRT (74 patients) and women who did not receive adjuvant PMRT (81 patients).
  
  
  RESULTS
  A total of 155 patients were included with a median follow-up period of 4.45 years. There was a statistically significant 4-year OS difference between the two groups of patients: 100% for the PMRT group and 93.1% for the non-PMRT group (P = 0.044). The 4-year RFS was 85.9% for patients receiving PMRT and 78.3% for patients who did not receive PMRT (P = 0.291). On multivariate analysis of OS, using hormonal treatment was the only significant independent factor associated with improved OS. On multivariate analysis of RFS, none of the variables were significantly associated with improved RFS. PMRT was notfound to be a prognostic variable related to the outcome of patients using a logistic regression model.
  
  
  CONCLUSIONS
  Our retrospective, hospital-based analysis demonstrated that PMRT improved the treatment outcome in terms of OS for women with 1-3 node positive early-stage breast cancer.
authors.affiliation: Division of Therapeutic Radiology and Oncology, Faculty of Medicine, Chiang Mai University, 110 Intawarorod Road, Chiang Mai, 50200, Thailand.
authors.forename: Imjai
authors.initials: I
authors.lastname: Chitapanarux
authors.forename: Ekkasit
authors.initials: E
authors.lastname: Tharavichitkul
authors.forename: Somvilai
authors.initials: S
authors.lastname: Jakrabhandu
authors.forename: Pitchayaponne
authors.initials: P
authors.lastname: Klunklin
authors.forename: Wimrak
authors.initials: W
authors.lastname: Onchan
authors.forename: Jirawattana
authors.initials: J
authors.lastname: Srikawin
authors.forename: Nantaka
authors.initials: N
authors.lastname: Pukanhaphan
authors.forename: Patrinee
authors.initials: P
authors.lastname: Traisathit
authors.forename: Roy
authors.initials: R
authors.lastname: Vongtama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D009367:Neoplasm Staging; D015995:Prevalence; D018714:Radiotherapy, Adjuvant / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D013785:Thailand / Q000453:epidemiology; D016896:Treatment Outcome
keywords: 1–3 positive nodes; Thai; breast cancer; postmastectomy radiotherapy