Trends in the kidney cancer incidence and mortality in the Slovak and Czech Republics in 1980-2005 - in the context of an international comparison.

Incidence rates of kidney cancer vary in global standards more than tenfold, the highest worldwide rates are repeatedly registered in the Czech Republic (hereafter CR) and in other geographically neighbouring countries in Central Europe, including the Slovak Republic (hereafter SR). The aim of the study was to analyse the changes in time trends of incidence and mortality from kidney cancer in two geographically close countries (CR and SR) and to compare detected differences with the worldwide data. In spite of high rates of incidence and its global growth in analyses in 1980 - 2005, the character of its progress in time was changed in both countries. While in 1980 - 1994 the incidence of kidney cancer in males and females in both analysed countries increased significantly, after 1994 (to 2005) stagnation in males in SR and significant slowdown of its growth in males in CR were reported. In females in SR after 1994 significant slowdown of the incidence growth was reported and in CR there was even its non-significant fall. Mortality trend in both sexes in both countries in 1980-2005 was slower than the incidence. After 1994 (to 2005) in males in SR statistically non-significant slowdown of mortality growth was reported, in CR it was statistically significant fall of mortality rates. In women after 1994 (to 2005) statistically non-significant decrease was reported, in CR the decrease was significant. The increase of total incidence of the disease is not explained only by the growth of asymptomatic localized tumors due to high quality diagnostic methods, but it likely reflects actual growth of new cases of the disease. Assumed partial cause of the mortality stabilization and slowdown of the incidence growth after its previous culmination in 1994 is the decline of smoking and obesity prevalence in the last decades in men, although this fact does not reflect situation in women. More striking mortality decrease in CR in comparison with SR might be influenced by potentially more radical surgical therapy (rate of the amount of surgery within primary therapy according to the data in National Cancer Registry CR raises, in SR the data are not available) and by more significant increase of the disease rate in the clinical stages I and II in CR (in SR only short-time data are available).