Abstract
BACKGROUND: Leukemia is cancer of the blood or bone marrow, characterized by an unusual increase in white blood cells. It is the sixth most common malignancy in the country in both males and females. The aim of this study was to document some epidemiological features of leukemia in the Northwest of Iran. METHODS: The study subjects (n=669, including 377 males and 292 females) comprised all leukemia cases registered/notified to the clinical and pathology centers of Tabriz and Ardebil cities, from 2003 to 2006. All patients were classified using the ICD-10 based coding system (C91-C95, C77 and C42). Ninety-five percent confidence intervals were calculated to assess the statistical significance of the data. RESULTS: Annual incidence of leukemia was 3.7 [95% CI: 3.3-4.0] and 4.9 [95% CI: 4.2-5.6] per 100 000 population in Tabriz and Ardebil, respectively, with an overall case fatality rate of 13.5 percent [95% CI: 10.8-16.0]. The sex ratio (male/female) was 1.23. Myeloid leukemia (C92) and Hematopoetic and Reticuloendothelial system (C42) accounted proportionally for more than 47 percent of cases in the region. Over the study period, the annual occurrence of leukemia in the region increased from 3.9 [95% CI: 3.4-4.5] to 4.1 [95% CI: 3.5-4.6] per 100 000 population (P>0.1). CONCLUSIONS: The data from this cross-sectional study of leukemia in the North-West of Iran may be used as the baseline information to establish a population-based registry of hema-tologic disorders in the area for health care and research purposes. However, more investiga-tions are needed to develop effective strategies to control the relevant disorders in high-risk groups.