Results of CT Scan

When you are diagnosed with cancer, typically you see three types of doctors; a surgeon, an oncologist and a radiation oncologist. My radiation oncologist is Dr. Hodgins and he was responsible for planning and executing my radiation treatment. The last time I had seen him was in late January when I was finishing up my treatment. He called me last week and wanted me to come in to see him since it had been awhile.
I told him that I had a CT scan last Thu but had not yet heard from my surgeon who had ordered the test. He was able to go on line and pull up the scan. The scan showed really good results. There were no masses, edema or swelling in my pelvis other than the original tumor which is now about 1.5 cm in size (originally it was over 6 cm in size). A CT scan will show the tumor mass but will not show metabolic activity. Metabolic activity indicates if the tumor is alive or dead. A PET scan will show tumor mass and metabolic activity but because of the amount of whole body radiation involved they don't want to do those very often. I am scheduled to have a PET at the end of July. He told me that what may happen is that in July when I have the PET scan it may show that there is a small mass still there but the mass is dead (no metabolic activity). He said if that is the case he would recommend that I not have the surgery to remove my anus and rectum. He said that he has most likely done so much damage to my anus and rectum with the radiation that it will not be able to function normally. That means that I would have the ileostomy for the rest of my life. He said the surgery to remove the anus and rectum is quite painful difficult with lots of side effects (Derek had read that it has a 5% mortality rate) and that I should avoid it if possible.
I guess I had thought that the tumor was either there or not. I never considered the possibility that it could still be there but dead. Wow....there is so much information to absorb. I feel like Derek and I will experts when this is all over.