FDG-PET and stereotactic body radiotherapy (SBRT) for stage I XXXX .

@entity1 @entity2495 @entity1149
PURPOSE: To investigate the utility of positron emission tomography (PET) in @entity1 treated with stereotactic body radiotherapy (SBRT) for stage I @entity1149 ( @entity1149 ) on prospective institutional trials. @entity1 AND METHODS: Fifty-eight @entity1 with medically inoperable stage I @entity1149 who participated in prospective phase I and II trials of SBRT, had >or=2 years of follow-up, and received FDG-PET imaging are the focus of this evaluation. Fifty-seven of 58 @entity1 received pre-SBRT FDG-PET to confirm stage I status. All @entity1 received stereotactic body frame immobilization and treatment with 7-10 photon beams. SBRT total doses ranged from 24 to 72Gy in three fractions. No elective nodal irradiation was undertaken. Regular follow-up with planned CT imaging was performed on all @entity1 . Post-SBRT FDG-PET was not mandated by protocol and was typically ordered upon concern for disease recurrence. Thirty-eight post-SBRT PET studies were performed in 28 @entity1 at a median 17.3 months following SBRT. RESULTS: With a median follow-up of 42.5 months, the 3-year actuarial overall survival and local control for this select subset of our SBRT experience were 48.9% and 74.8%, respectively. Pre-SBRT FDG-PET SUV did not predict 3-year overall survival or local control. Fourteen of 57 @entity1 eventually failed in nodal stations by CT and/or PET. Isolated first site of failure was nodal in 6 @entity1 (10%). Out of 28 @entity1 with post-SBRT PET, 4 (14%) had delayed PET imaging (22-26 months after SBRT) showing moderate @entity2495 activity (SUV 2.5-5.07), but no evidence of local, nodal, or distant recurrence by clinical examination and conventional imaging performed 20-26 months following these concerning PET findings. CONCLUSIONS: Isolated nodal recurrence following PET-staged I @entity1149 treated with SBRT is uncommon. Moderate post-SBRT PET @entity2495 activity may persist 2 years following treatment without definite evidence of recurrence. Further study is needed to confirm these results in larger populations with longer follow-up.
