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Title: Timing of Radiotherapy and Outcome in Patients Receiving Adjuvant Endocrine Therapy

Journal Article · · International Journal of Radiation Oncology, Biology and Physics
 [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10]
  1. Department of Oncology, Sahlgrenska University Hospital, Gothenburg (Sweden)
  2. Department of Mathematics and Statistics, University of Vermont College of Engineering and Mathematical Sciences, Burlington, VT (United States)
  3. Department of Medicine, Research Unit in Medical Senology, European Institute of Oncology, Milan (Italy)
  4. Department of Radiotherapy, Centro di Riferimento Oncologico, Aviano (Italy)
  5. Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne (Australia)
  6. Department of Radiation Oncology, Groote Shuur Hospital and University of Cape Town, Cape Town (South Africa)
  7. International Breast Cancer Study Group Statistical Center, Frontier Science and Technology Research Foundation, Boston, MA (United States)
  8. International Breast Cancer Study Group Coordinating Center, Bern (Switzerland)
  9. European Institute of Oncology, Milan (Italy)
  10. Institut fuer Radiotherapie, Klinik Hirslanden, Zuerich (Switzerland)

Purpose: To evaluate the association between the interval from breast-conserving surgery (BCS) to radiotherapy (RT) and the clinical outcome among patients treated with adjuvant endocrine therapy. Patients and Methods: Patient information was obtained from three International Breast Cancer Study Group trials. The analysis was restricted to 964 patients treated with BCS and adjuvant endocrine therapy. The patients were divided into two groups according to the median number of days between BCS and RT and into four groups according to the quartile of time between BCS and RT. The endpoints were the interval to local recurrence, disease-free survival, and overall survival. Proportional hazards regression analysis was used to perform comparisons after adjustment for baseline factors. Results: The median interval between BCS and RT was 77 days. RT timing was significantly associated with age, menopausal status, and estrogen receptor status. After adjustment for these factors, no significant effect of a RT delay {<=}20 weeks was found. The adjusted hazard ratio for RT within 77 days vs. after 77 days was 0.94 (95% confidence interval [CI], 0.47-1.87) for the interval to local recurrence, 1.05 (95% CI, 0.82-1.34) for disease-free survival, and 1.07 (95% CI, 0.77-1.49) for overall survival. For the interval to local recurrence the adjusted hazard ratio for {<=}48, 49-77, and 78-112 days was 0.90 (95% CI, 0.34-2.37), 0.86 (95% CI, 0.33-2.25), and 0.89 (95% CI, 0.33-2.41), respectively, relative to {>=}113 days. Conclusion: A RT delay of {<=}20 weeks was significantly associated with baseline factors such as age, menopausal status, and estrogen-receptor status. After adjustment for these factors, the timing of RT was not significantly associated with the interval to local recurrence, disease-free survival, or overall survival.

OSTI ID:
21491774
Journal Information:
International Journal of Radiation Oncology, Biology and Physics, Vol. 80, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2010.02.042; PII: S0360-3016(10)00334-2; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
Country of Publication:
United States
Language:
English