FDG-PET and stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer.
OBJECTIVE
To investigate the utility of positron emission tomography (PET) in patients treated with stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) on prospective institutional trials.


METHODS
Fifty-eight patients with medically inoperable stage I NSCLC 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 patients received pre-SBRT FDG-PET to confirm stage I status. All patients 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 patients. 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 patients 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 patients eventually failed in nodal stations by CT and/or PET. Isolated first site of failure was nodal in 6 patients (10%). Out of 28 patients with post-SBRT PET, 4 (14%) had delayed PET imaging (22-26 months after SBRT) showing moderate hypermetabolic 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 NSCLC treated with SBRT is uncommon. Moderate post-SBRT PET hypermetabolic 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.
Hoopes
David J
DJ
Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN, United States.
Tann
Mark
M
Fletcher
James W
JW
Forquer
Jeffrey A
JA
Lin
Pei-Fen
PF
Lo
Simon S
SS
Timmerman
Robert D
RD
McGarry
Ronald C
RC
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D016634:Radiosurgery; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18