Hey mate, I got back into it slowly, but I knew i had to build myself up for the lung op. Then post the lung op I just walked to start with, but, within a few months of having my lung chopped I was doing 1 hr cardio classes at gym....then it all came to a crashing halt with the 5cm tumor in my lung needing to be "fried" to steal your term!! I am just starting walking agin now and I am like months past treatment. But this last treatment has really affected the condition of my lung and breathing. But I'm slowly getting there....also have 10kilos extra to drag around with me know!!!
Just take it easy, let your body be your guide and don't push yourself.
Cheers
Shell xx
P.S. i'm about to PM you!