Conversation: The conversation between human and AI assistant.
[|Human|] Hi, my mother has just found out she has stage 3 going into stage 4 lung cancer. My question is she never had breathing problems until about three months ago. And they said she also has COP. Her doctor said that come from smoking forty years ago. Is this true.
[|AI|]  Thanks for your question on Chat Doctor. I can understand your concern. Yes, previous history of smoking can cause lung cancer at present. Cigarette smoke causes permanent damage to cells. When these cells are under malignant transformation, they great tumor nodule which slowly progress into lung cancer. Besides smoking, COPD is also a risk factor for lung cancer. So carcinogenic effect of smoking is aggravated by COPD and combination of both these cause lung cancer in her. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.