Standardized Breast Cancer Mortality Rate Compared to the General Female Population of Iran

Introduction: Breast cancer is the most common cancer in women.Improvements of early diagnosis modalities have led to longer survival rates. Thisstudy aimed to determine the 5, 10 and 15 year mortality rates of breast cancerpatients compared to the normal female population. Materials and Methods: Thefollow up data of a cohort of 615 breast cancer patients referred to IranianBreast Cancer Research Center (BCRC) from 1986 to 1996 was considered asreference breast cancer dataset. The dataset was divided into 5 year age groupsand the 5, 10 and 15 year probability of death for each group was estimated. Theannual mortality rate of Iranian women was obtained from the Death Registrysystem. Standardized mortality ratios (SMRs) of breast cancer patients werecalculated using the ratio of the mortality rate in breast cancer patients over thegeneral female population.Results: The mean age of breast cancer patients at diagnosis time was 45.9(±10.5) years ranging from 24-74. A total of 73, 32 and 2 deaths were recorded at5, 10 and 15 years, respectively, after diagnosis. The SMRs for breast cancerpatients at 5, 10 and 15 year intervals after diagnosis were 6.74 (95% CI, 5.5-8.2), 6.55 (95%CI, 5-8.1) and 1.26 (95%CI, 0.65-2.9), respectively. Conclusion:Results showed that the observed mortality rate of breast cancer patients after 15years from diagnosis was very similar to expected rates in general femalepopulation. This finding would be useful for clinicians and health policy makersto adopt a beneficial strategy to improve breast cancer survival. Further follow-uptime with larger sample size and a pooled analysis of survival rates of differentcentres may shed more light on mortality patterns of breast cancer.