Usually 1 month. Once tumors have spread in the lungs, surgery is no longer an option. It is better to make peace and be ready to travel than it is to attempt chemo or radiation in stage 4 lung cancer. Many stage 4 cancers are untreatable without even furthering damage.
No exact figures as each case different. Recommend reading the Cancer Research statistics by following link below :-
www.cancerhelp.org.uk
www.cancerhelp.org.uk