Clarification on a few things! - 1247825

No, radiation doesn't cause COPD, but it can cause damage to lung tissues that can make radiated lung tissue not function, and this can be added to the loss of lung function from COPD that developed from other causes.

Stage IIIB and stage IV aren't really thought of the same way, even if they have somewhat similar prognoses. The difference is that, with the exception of what was previously called "wet IIIB" with a pleural effusion and should now be categorized as stage IV, stage IIIB NSCLC can still be treated with curative intent, while stage IV is really not conventionally considered to be curable. That's a significant difference.

-Dr. West