Lung cancer is an illness.
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body . Lung cancer . Worldwide in 2012 , lung cancer occurred in 1.8 million people and resulted in 1.6 million deaths . Overall , 17.4 % of people in the United States diagnosed with lung cancer survive five years after the diagnosis , while outcomes on average are worse in the developing world .