My mother completed SBRT for a LUL stage 1B lung tumor, no confirmed biopsy, with 5 treatments of 10Gy on November 21, 2012 (5 wks ago). At time of diagnosis PET SUV was 10.5 and 1.5 for adjustcent nodule, with CEA > 20. I have the following questions and would greatly appreciate your opinion.
1. After how long post treatment would it be reasonable to expect the SUV/level off and repeat the PET scan?
2. When would treatment reflect in the blood CEA counts?
3. Can CT lung scan show increased size at this point (5wks post treatment) due to inflammation?
My mother's radiation oncologist did repeat CT last week, and wants to wait 12 weeks post SBRT to repeat PET scan.
On the other hand medical onc wants to repeat PET 6 wks post SBRT and expects CEA to go to 0 by then.
Which one of these would be the followup protocol? I've read her lung is probably a 'mess' right now. Just wondering if it's too soon to make a treatment decision should the CT scan show a larger mass or PET SUV not 0 or CEA not 0.
Thanks for your help and Happy Holidays!