title: Simulations model for predicting survival in women receiving adjuvant therapy for early breast cancer.
abstract: OBJECTIVE
  In 1990, a worldwide overview of the randomized trials of all aspects of the systemic treatment of early breast cancer was undertaken by the Early Breast Cancer Trialists' Collaborative Group. We used the overview data to develop a simulations model to assess and compare the potential benefits of various adjuvant therapies.
  
  
  METHODS
  The model consists of an expert system, a simulations module, a graphical user interface, and an output module.
  
  
  RESULTS
  The model has shown that tamoxifen benefited all women regardless of age or estrogen-receptor status. However, absolute gains in disease-free survival and life expectancy compared with controls were higher in women younger than 50 years of age. Prolonged chemotherapy showed absolute benefits in disease-free survival and life expectancy for all age groups and all nodal states, but the magnitude of absolute benefit appeared smaller in older women. The magnitude of the absolute gain in disease-free survival and life expectancy achieved by ovarian ablation in patients younger than 50 years of age was equal to or better than that attained by tamoxifen or prolonged chemotherapy. Ovarian ablation added to chemotherapy in young patients has demonstrated an improvement in disease-free survival and life expectancy superior to that achieved by chemotherapy alone. On the other hand, particularly for women younger than 50 years, the magnitude of the survival gain accomplished by combining tamoxifen and chemotherapy versus each modality alone was greater for disease-free survival than for life expectancy.
  
  
  CONCLUSIONS
  We illustrate the development process and outcome of a robust tool for reasoning and decision-making. The limitations of the model are discussed.
authors.affiliation: College of Medicine and Medical Sciences, King Faisal University, Al-Khobar, Saudi Arabia.
authors.forename: E M
authors.initials: EM
authors.lastname: Ibrahim
authors.forename: F M
authors.initials: FM
authors.lastname: Nassim
authors.forename: R E
authors.initials: RE
authors.lastname: Ibrahm
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality*; D017024:Chemotherapy, Adjuvant; D002986:Clinical Trials as Topic; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008017:Life Expectancy; D008875:Middle Aged; D008954:Models, Biological; D015996:Survival Rate