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Cigarette smoking and trends in lung cancer incidence in Lithuania: an analysis by histological type.

OBJECTIVE
The aim of this study was to investigate time trends of lung cancer incidence by histological type in Lithuania during the period from 1996 to 2005. The results were evaluated in relation to tobacco smoking trends.


MATERIAL AND METHODS
The incidence rates of the most common lung cancer cell types (squamous cell carcinoma, adenocarcinoma, small cell carcinoma, other types, and morphologically not specified cases) were studied using data from the Lithuanian Cancer Registry. The world standard population was used for age adjustment. Data on tobacco smoking in Lithuania were obtained from various published sources.


RESULTS
Among men, squamous cell carcinoma was the most common type of lung cancer. The age-adjusted rates of squamous cell carcinoma decreased from 25 per 100,000 in 1998-1999 to 19.1 per 100,000 in 2004-2005; the incidence rates for adenocarcinoma and small cell carcinoma rose to around 7 per 100,000 in 2002-2003. Among women, adenocarcinoma was the most common histological type. The incidence rates for adenocarcinoma increased to 1.9 per 100,000 until 2002-2003 and thereafter did not change. The rates of squamous cell carcinoma in women were relatively stable at around 1.1 per 100,000. In 2000, the prevalence of regular smoking among men and women peaked at 51.5% and 15.8%, respectively; there was a significant change from smoking nonfilter cigarettes to filter cigarettes.


CONCLUSIONS
The decreasing squamous cell carcinoma rates among men and increasing adenocarcinoma rates among men and women are similar to those reported in other European countries and may be due to a shift from nonfilter type cigarettes to filter type.