title: Eleven-year follow-up results in the delay of breast irradiation after conservative breast surgery in node-negative breast cancer patients.
abstract: OBJECTIVE
  This retrospective review was conducted to determine if delay in the start of radiotherapy after conservative breast surgery had any detrimental effect on local recurrence or disease-free survival in node-negative breast cancer patients.
  
  
  METHODS
  A total of 568 patients with T1 and T2, N0 breast cancer were treated with breast-conserving surgery and breast irradiation, without adjuvant systemic therapy, between January 1, 1985 and December 31, 1992 at the London Regional Cancer Centre. The time intervals from definitive breast surgery to breast irradiation used for analysis were 0 to 8 weeks (201 patients), greater than 8 to 12 weeks (235 patients), greater than 12 to 16 weeks (91 patients), and greater than 16 weeks (41 patients). Kaplan-Meier estimates of time to local-recurrence and disease-free survival rates were calculated.
  
  
  RESULTS
  Median follow-up was 11.2 years. Patients in all 4 time intervals were similar in terms of age and pathologic features. No statistically significant difference was seen between the 4 groups in local recurrence or disease-free survival with surgery radiotherapy interval (p = 0.521 and p = 0.222, respectively). The overall local-recurrence rate at 5 and 10 years was 4.6% and 11.3%, respectively. The overall disease-free survival at 5 and 10 years was 79.6% and 67.0%, respectively.
  
  
  CONCLUSIONS
  This retrospective study suggests that delay in the start of breast irradiation of up to 16 weeks from definitive surgery does not increase the risk of recurrence in node-negative breast cancer patients. The certainty of these results is limited by the retrospective nature of this analysis.
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Centre, London, Ontario, Canada. olga.vujovic@lhsc.on.ca
authors.forename: Olga
authors.initials: O
authors.lastname: Vujovic
authors.forename: Edward
authors.initials: E
authors.lastname: Yu
authors.forename: Anil
authors.initials: A
authors.lastname: Cherian
authors.forename: A Rashid
authors.initials: AR
authors.lastname: Dar
authors.forename: Larry
authors.initials: L
authors.lastname: Stitt
authors.forename: Francisco
authors.initials: F
authors.lastname: Perera
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018275:Carcinoma, Lobular / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors