The lung cancer did not exsist in the early 1900's. Although this epademic happened in 1977 and it Worried the whole world. However the lung cancer is usually caused by smoking or it is caused by a certain gas. This problem was so serious because most people who smoke and have lung cancer but they don't know it until they see a doctor or surgen. Most people know that smoking can increase the risk of lung cancer, and sometimes it can be cured.most people have to live with it for the rest of their lives.