[Effect of the level of "tar" in tobacco smoke on the risk of the occurrence of malignant tumors].

Carcinogenic effect exerted by smoking on people depends on the chemical composition of tobacco smoke. It has been shown that relative risk of lung cancer, as well as its incidence and mortality are closely related to "tar" yield. Cigarettes produced in the USSR contain still high levels of "tar" and nicotine. A decrease of "tar" levels in the Soviet cigarettes may cause in 15-20 years a substantial reduction of lung cancer incidence and mortality in young and middle-aged people.