Long-term Survival and Prognostic Factors of Breast Cancer

Background: Breast cancer survival rate is an important index for assessment of treatment effect in reducing the mortality. We aimed to determine the fifteen-year survival rate for breast cancer at a referral center in Iran and its correlated factors.Methods: This survival study enrolled patients with breast cancer who referred to Motamed Cancer Institute (MCI) from 1998 to 2016. The survival rate was calculated using the Kaplan-Meier method. The relationship of demographic, clinical and therapeutic factors with overall survival (OS) was studied using Cox's proportional hazard model.Results: Totally, 3443 patients were studied. Their mean age and follow-up period were 47.7 ( +/- 11.43) years and 61.66 ( +/- 52.1) months, respectively. The median follow-up time was 48.4 months (range: 1-413 months), 49.7% of the patients had high school or higher education, and 71.3% presented in the early stage of the disease. Death occurred in 505 (14.7%) of the patients. The overall 2-, 5-, 7-, 10-and 15-year survival rates were 93%, 82%, 78%, 74%, and 66%, respectively. Lymph node involvement (HR = 2.07; 95% CI: 1.38-3.09), tumor size >= 5 cm (HR = 2.83; 95% CI: 1.59-2.04), being single/divorced/widowed (HR = 1.65; 95% CI: 1.13-2.4), and education level < high school diploma (HR = 1.57; 95% CI: 1.13-2.17) were independent predictors of breast cancer survival.Conclusion: The five-year breast cancer survival rate in this study was higher than reported by some other studies in Iran, which could be due to the multidisciplinary treatment approach in MCI. Tumor size and lymph node involvement as indicators of delayed diagnosis may affect breast cancer survival, even though their true effect due to lead-time bias should be considered. The correlation of education level with survival confirms the importance of awareness and the need to establish strategies for early diagnosis in Iranian women.