Risk Factors of Metastasis in Women with Breast Cancer in Isfahan, Iran

Breast cancer is one of the most common malignancies in women and its metastasis plays an important role in mortality, treatment failures and complications. The objective of this study was to evaluate the risk factors of metastatic breast cancer. In a retrospective cohort study, breast cancer patients in Isfahan, Iran were followed up for ten years. The existence of metastasis was considered as the dependent variable while independent variables included age at diagnosis, hormone receptor status, family history, number of lymph nodes dissected in surgery and involved ones, number of pregnancies, age at first pregnancy and menarche, menstrual status, histopathology and tumor size. All data was collected from patient's profiles and analyzed using logistic regression in SPSS16. A total of 685 patients with breast cancer were studied during 1999-2009. While 91.4% of cases had no metastasis, distant metastasis was found in 8.6% of subjects. Sites of metastasis according to prevalence were lung (4.7%), bone (2.6%), other organs (1.1%), and liver (0.3%). Number of involved lymph nodes (P = 0.043) and number of pregnancies (P = 0.022) had significant relationships with metastasis. We concluded that less pregnancies and more involved lymph nodes indicate a high probability of metastasis occurrence. Therefore, survival improvement might be possible with early diagnosis of breast cancer, using prophylactic treatments, and identifying metastatic cases by diagnostic tests.