title: Radiation therapy and survival in breast cancer patients with 10 or more positive axillary lymph nodes treated with mastectomy.
abstract: OBJECTIVE
  Adjuvant loco-regional radiation (XRT) frequently is recommended after mastectomy and adjuvant systemic therapy in patients with 10 or more positive axillary lymph nodes (ALN) to reduce the high loco-regional failure rate observed in this subset. In this study, we explored the possibility that adjuvant loco-regional radiation therapy (LR-XRT) also could decrease distant failure and improve overall survival (OS) in this subset of poor-prognosis patients.
  
  
  METHODS
  Retrospectively, 618 breast patients with 10 or more positive ALN were studied. The median follow-up time was 7.5 years. All patients received systemic adjuvant therapy and 35% also received adjuvant radiation therapy. Loco-regional failure, distant failure, and OS analyses were adjusted for age, tumor size, number of positive ALN, and estrogen receptor (ER) status using Cox regression model.
  
  
  RESULTS
  As expected, patients had a very high risk of loco-regional and distant failure. At 5 years, 30% of patients had loco-regional failure as a first event and 54% had distant failure. Radiation dramatically reduced loco-regional failure (hazards rate ratios [RR]=0.29; 95% confidence interval [CI], 0.19 to 0.45). The adjusted 5-year loco-regional failure rate was 13% with radiation and 38% without radiation (P=.0001). Radiation also was associated with improved distant control (RR=0.75; 95% CI, 0.58 to 0.96). The adjusted 5-year distant failure rate was 48% with radiation and 58% without radiation (P=.02). OS also improved with radiation (RR=0.68; 95% CI, 0.53 to 0.85). The adjusted 5-year OS was 56% with radiation and 42% without radiation (P=.001).
  
  
  CONCLUSIONS
  In this cohort of high-risk breast cancer patients, XRT was associated with less loco-regional and distant failure and improved OS. This suggests that improved loco-regional control might decrease secondary systemic spread and improve survival.
authors.affiliation: Division of Medical Oncology, University of Texas Health Science Center at San Antonio, 78284-7884, USA. sami_diab@oncology.uthscsa.edu
authors.forename: S G
authors.initials: SG
authors.lastname: Diab
authors.forename: S G
authors.initials: SG
authors.lastname: Hilsenbeck
authors.forename: C
authors.initials: C
authors.lastname: de Moor
authors.forename: G M
authors.initials: GM
authors.lastname: Clark
authors.forename: C K
authors.initials: CK
authors.lastname: Osborne
authors.forename: P M
authors.initials: PM
authors.lastname: Ravdin
authors.forename: R M
authors.initials: RM
authors.lastname: Elledge
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D018714:Radiotherapy, Adjuvant; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate