title: Time interval from breast-conserving surgery to breast irradiation in early stage node-negative breast cancer: 17-year follow-up results and patterns of recurrence.
abstract: OBJECTIVE
  A retrospective chart review was conducted to determine whether the time interval from breast-conserving surgery to breast irradiation (surgery-radiation therapy interval) in early stage node-negative breast cancer had any detrimental effects on recurrence rates.
  
  
  METHODS
  There were 566 patients with T1 to T3, N0 breast cancer treated with breast-conserving surgery and breast irradiation and without adjuvant systemic treatment between 1985 and 1992. The surgery-to-radiation therapy intervals used for analysis were 0 to 8 weeks (201 patients), >8 to 12 weeks (233 patients), >12 to 16 weeks (91 patients), and >16 weeks (41 patients). Kaplan-Meier estimates of time to local recurrence, disease-free survival, distant disease-free survival, cause-specific survival, and overall survival rates were calculated.
  
  
  RESULTS
  Median follow-up was 17.4 years. Patients in all 4 time intervals were similar in terms of characteristics and pathologic features. There were no statistically significant differences among the 4 time groups in local recurrence (P=.67) or disease-free survival (P=.82). The local recurrence rates at 5, 10, and 15 years were 4.9%, 11.5%, and 15.0%, respectively. The distant disease relapse rates at 5, 10, and 15 years were 10.6%, 15.4%, and 18.5%, respectively. The disease-free failure rates at 5, 10, and 15 years were 20%, 32.3%, and 39.8%, respectively. Cause-specific survival rates at 5, 10, and 15 years were 92%, 84.6%, and 79.8%, respectively. The overall survival rates at 5, 10, and 15 years were 89.3%, 79.2%, and 66.9%, respectively.
  
  
  CONCLUSIONS
  Surgery-radiation therapy intervals up to 16 weeks from breast-conserving surgery are not associated with any increased risk of recurrence in early stage node-negative breast cancer. There is a steady local recurrence rate of 1% per year with adjuvant radiation alone.
authors: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada. Electronic address: olga.vujovic@lhsc.on.ca.
authors: Olga
authors: O
authors: Vujovic
authors: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada.
authors: Edward
authors: E
authors: Yu
authors: Station Health Centre, Royal Air Force Lossiemouth, Moray, United Kingdom.
authors: Anil
authors: A
authors: Cherian
authors: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada.
authors: A Rashid
authors: AR
authors: Dar
authors: Department of Biometry, London Regional Cancer Program, London, Ontario, Canada.
authors: Larry
authors: L
authors: Stitt
authors: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada.
authors: Francisco
authors: F
authors: Perera
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008207:Lymphatic Metastasis; D015412:Mastectomy, Segmental / Q000401:mortality*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control*; D009367:Neoplasm Staging; D009864:Ontario / Q000453:epidemiology; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome