Lung cancer: stage 4

Lung cancer is a terrible diagnosis, which every year is like a sentence, I hear many citizens of our country. Because of this disease survives no more than fifteen percent of patients, claiming one million lives per year worldwide. This disease occurs because of damage to cell DNA by the impact of unfavorable factors from the external environment. Such factors may be Smoking, work associated with hazardous substances in industries, inhalation of various harmful substances such as tar, coke, esters. Also the emergence of this disease may be preceded by chronic inflammatory processes in the respiratory tract. There are two varieties of this disease: small cell and small cell does not, which is divided into four stages.