Mahmood Reza Gohari - Associate Professor, Hospital Management Research Center, Iran University of Medical Sciences,Tehran, Iran
Parisa Mokhtari Hesari - M.Sc. of Biostatistics, Cancer Quality of Life Department, Breast Cancer Research Center, ACECR,Iran
Zeinab Moghadami Fard - M.Sc. of Biostatistics, Department of Health Management and Information Sciences, TehranUniversity of Medical Sciences, Tehran, Iran
Reza khodabakhshi - Oncologist, Oncology department, Fayazbakhsh Hospital

identifying the risk factors for metastasis is major concern for treatment processes of cancer patients. Metastasis makes patients frail and increase hazard of death. It also decreases physical and psychological quality of life of patients. Aim of this study is determining of prognostic factors formetastasis of breast cancer using conditional regression model. Materials and Methods: in this survival study, hospital records of 246 women with breast cancer who underwent surgery and treatment at hospital Fayyazbakhsh were used. Patients were followed and their final situations recorded until 2012 May. Metastasis free survival estimated with Kaplan-Myier method. To determine the prognostic factors, a conditional regression model called PWP fitted. All statistical analysis was conducted with R software.Results: 202 patients (82.1%) were alive until follow up and 44 patients (17.9%) died.54patients experience metastasis. 11 patients (4.7%) had two metastases. Most of metastases were shown in bone, liver, lung and brain. Median metastasis free survival (MFS) estimated 64 month. One, two and three year MFS were 88%, 80.1% and 76.6%, respectively. Lymph node involvement and HER2 were shown as prognostic factors for metastasis. Age, Estrogen Receptor, Progesterone Receptor, Grade and tumor size variables were not significant (P> 0.05). Conclusions: number of lymph nodes involvement as a prognostic factor involve more nodes and increase risk of metastasis and death. Thus prognosis and treatment of cancer in early stages increase survival of patients.

Breast cancer, Metastasis, Metastasis free survival, Conditional model