It's a good question. Nobody has done a study like that. One could do it. That would be something that the CIHR, the Instituts de recherche en santé du Canada, should get into, because it's worth it.
You can almost pick them out. Typically, a non-smoker radon-exposed person would have a typical non-smoking cancer. They would have an adenocarcinoma with an early presentation at a late stage that was very sensitive to treatment. They would more likely be a woman. If they're also a smoker, on the other hand, they would tend to approach a smoker's type of cancer, which is a squamous cell cancer, more likely small cell, more likely less advanced at time of diagnosis, presenting based on an X-ray, not on symptoms, and not very responsive to treatment.
If you smoke, it pushes it towards the smoking zone.