Background. For stage I and II breast cancer, the standard treatment is partial mastectomy followed by radiation treatment. The risk of local recurrence ranges from 6 to 9%. A controversy exists as to whether there is an increased risk of local recurrence as a result of excessive delay between surgery and radiation treatment. A natural experiment associated with a prolonged waiting time in our institution provided an opportunity to evaluate the impact of waiting times for radiation treatment of breast cancer on the risk of local recurrence. / Methods. Between January 1988 and December 1989, 486 patients with stage I or II breast cancer from McGill hospitals were treated with radiotherapy. Their charts were reviewed, and information with regard to prognostic factors, such as age, tumor size, histological grade, number of positive lymph nodes, and margins of resection, was abstracted. The interval between the date of surgery and the date of initial radiation treatment, and events, such as local recurrence, metastases and death, were noted. / Results. At five years, the local recurrence rate was 8%, the metastatic rate 13%, and the disease-free survival rate 89%. In the univariate analysis, the risk of local recurrence was associated with younger age, higher histological grade, and time to radiation treatment. In the multivariate Cox proportional hazard models, higher histological grade and time to radiation treatment were significant. Using recursive partitioning, the risk of local recurrence was almost five times higher for patients who waited in excess of 79 days for radiation treatment. / Conclusion. Delay in radiation treatment is associated with an increased risk of local recurrence of breast cancer.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.29873 |
| Date | January 1999 |
| Creators | Benk, Véronique. |
| Contributors | Battista, R. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Epidemiology and Biostatistics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001681972, proquestno: MQ55038, Theses scanned by UMI/ProQuest. |
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