Long-term Survival and Prognostic Factors of Breast Cancer.

Abstract

Breast cancer survival rate is an important index for assessment of treatment effect in reducing the mortality. Weaimed to determine the fifteen-year survival rate for breast cancer at a referral center in Iran and its correlated factors. This survival study enrolled patients with breast cancer who referred to Motamed Cancer Institute (MCI) from 1998 to2016. The survival rate was calculated using the Kaplan-Meier method. The relationship of demographic, clinical and therapeuticfactors with overall survival (OS) was studied using Cox's proportional hazard model. 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 schoolor higher education, and 71.3% presented in the early stage of the disease. Death occurred in 505 (14.7%) of the patients. Theoverall 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 ofbreast cancer survival. The five-year breast cancer survival rate in this study was higher than reported by some other studies in Iran, whichcould be due to the multidisciplinary treatment approach in MCI. Tumor size and lymph node involvement as indicators ofdelayed diagnosis may affect breast cancer survival, even though their true effect due to lead-time bias should be considered. Thecorrelation of education level with survival confirms the importance of awareness and the need to establish strategies for earlydiagnosis in Iranian women.