It all depends on the stage lung cancer is found in. It is usually not detected until an advanced stage when it is harder to treat. My brother was diagnosed at stage 3b lung cancer a little over 8 months ago and given 1 to 5 years survival. Unfortunately, he only made it 8 months. There are too many variables to really predict the outcome.
If you open the door even a little bit - the devil will fling it open. Keep it closed with prayer.
My brother-in-law was diagnosed with inoperable lung cancer about 10 years ago and was discouraged by the cancer specialists in his town to consider the quality of life should he consider chemo. He and his wife flew to Houston and got a second opinion. They disagreed totally and told them they felt he had an extremely good chance of overcoming it. It would have one of 2 effects: either it would do nothing or it would wipe it out. B/c his health was extremely good, they gave a very, very strong regiment of chemo. After many months of this after they felt his body had taken all it could take, they stopped the treatments did a scan and it showed only a small amount left. They told him that the chemo still in his body would continue to fight that and that it would probably get it. Can't remember exactly when this was but I know it had to be at least 10 years ago. He goes for a yearly check up now and so far it has been cleaned. So yes, there are survivors. And this was his 2nd bout with lung cancer. Just a few years before that, an xray by accident found a spot on his lung. 5 surgeons consulted - 3 said to wait and 2 said to operate. He chose to operate to remove that part of his lung.
So, don't hesitate to be extremely agressive and go for a 2nd opion.