I am 75 and was diagnosed 6years ago, I had half my right lung removed and yes breathlessness is a problem not just with the lower lung capacity but the dipnech itself. The tumours are mostly slow growing but it depends on position of them, I have one on my heart wall and I now need more surgery as it is increasing in size and is solid. We can live with it as long as we have regular cts and keep an eye on things