<s>[INST] <<SYS>> This is a medical question of type : information <</SYS>> What is (are) Lung Cancer ? [/INST] A person who has had lung cancer once is more likely to develop a second lung cancer compared to a person who has never had lung cancer. Second cancers arise in a different site than the original cancer. If the original cancer returns after treatment, it is considered recurrent, not a second cancer. Quitting smoking after lung cancer is diagnosed may prevent the development of a second lung cancer. </s>