title: Impact of delayed radiotherapy on local control in node-negative breast cancer patients treated with breast-conserving surgery and adjuvant radiotherapy without chemotherapy.
abstract: OBJECTIVE
  To evaluate the effect of the surgery-radiotherapy interval (SRI) on local control in node-negative breast cancer patients treated with breast-conserving surgery and adjuvant radiotherapy without chemotherapy.
  
  
  METHODS
  From February 1992 to January 2002, 171 patients with node-negative breast cancer underwent breast-conserving surgery and adjuvant radiotherapy without chemotherapy. The whole breast was irradiated up to 50.4 Gy in 28 fractions followed by a 10-Gy boost to the tumor bed. Forty-four patients received tamoxifen in addition to radiotherapy. Patients were divided into 2 groups according to the length of SRI: <6 weeks (128 patients) versus ≥6 weeks (43 patients). The median follow-up period was 87 months (range, 22-167).
  
  
  RESULTS
  The 8-year local control rates of patients with SRI <6 weeks and ≥6 weeks were 94.5% and 92.7%, respectively (P = 0.1140). When age, tumor size, resection margin status, combination with hormonal therapy, and SRI were incorporated into the Cox proportional hazards model, SRI <6 weeks and age at diagnosis ≥40 years were associated with increased local control (P = 0.0343 and 0.0264, respectively). In the subgroup analysis, SRI <6 weeks was correlated with a higher local control rate for patients aged <40 years (P = 0.0142). Among older patients, however, there was no statistical difference in local control according to SRI (P = 0.6655). Treatment interval had no impact on overall and distant metastasis-free survival.
  
  
  CONCLUSIONS
  Early radiotherapy within 6 weeks of breast-conserving surgery is associated with increased local control in patients with node-negative breast cancer not undergoing chemotherapy.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyubo
authors.initials: K
authors.lastname: Kim
authors.forename: Eui Kyu
authors.initials: EK
authors.lastname: Chie
authors.forename: Wonshik
authors.initials: W
authors.lastname: Han
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.forename: Sung W
authors.initials: SW
authors.lastname: Ha
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000532:radiotherapy* / Q000601:surgery*; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011878:Radiotherapy / Q000379:methods; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal