They found a mass on my lung and also I had pneumonia , The mass shrunk on the pet scan,that was 3 weeks after they first found it and are doing a CT scan in 3 months. Now a woman from my Facebook page said her husband mass shrunk on its own and that I should get them to do a biopsy now and not wait if she had waited for the follow up CT her husband might not be here today. he has his last treatment today . so now I am a wreck and wondering if I should push for a biopsy or wait and see what happens in 3 months ? Help ! Has anyone else had a mass shrink before treatment and then turned out to be cancer ?