Laryngeal cancer in Kazakhstan - ethnic, age and gender differences over time.

The purpose of the present study was to provide an assessment of the incidence of cancer of the larynx in Kazakhstan with especial attention to ethnicity and gender, as well as age. The retrospective design covered all new cases of laryngeal cancer in 11 years (1999-2009). The total number was 4,967 cases, 4,535 (91.3%) in males and 432 (8.7%) in women, with a gender ratio of 10.5:1. Patients of Kazakh (31.2%) and Russian (51.4%) ethnicity accounted for the vast majority (82.6%), with Russians predominating in both sexes, but particularly in females. Age peak in Kazakhs was 70 years and older (14.6 ± 0.70/0000), and in Russians was 60-69 years (21.6 ± 1.30/0000). In the dynamics, the rates had the tendency to decrease more markedly in Russian than Kazakh men, especially in the younger groups, while increase was noted in the youngest females of both ethnicities, but again greater in Russians, presumably reflecting change in underlying lifestyle factors.