Hi, Thanks for writing in. The cancer seems to be under control for you but the COPD requires close monitoring. The PET scan shows you are clear from cancer and have also been treated with brain radiation therefore the cancer is less likely to be a cause of concern. However you should always keep a close watch for any health related problems which might indicate recurrent cancer. Please follow up with your oncologist regularly. The COPD is a condition where there is obstruction to the flow of air in the smaller airways which is persistent. You require to do spirometry and lung function tests to know your lung volumes and with medicines and oxygen you might be able to maintain almost normal lung functioning. The survival rates of COPD depends on the stage of condition but it has higher survival than cancer. You might like to have small frequent meals and increase your breathing capacity by doing breathing rehabilitation techniques. Please do not worry.