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 . Most cancers that start in the lung , known as primary lung cancers , are carcinomas . Treatment and long-term outcomes depend on the type of cancer , the stage ( degree of spread ) , and the person 's overall health . This makes it the most common cause of cancer-related death in men and second most common in women after breast cancer .