Stereotactic body radiotherapy (SBRT) for non-small cell lung cancer (NSCLC): is FDG-PET a predictor of outcome?
OBJECTIVE
Distant metastases are the dominant mode of failure after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC). The primary study objective was to evaluate if the maximum standardized uptake value (SUV(max)) on pre-treatment FDG-PET/CT predicted clinical outcomes. Secondary objectives were to correlate 3-month post-SBRT SUV(max) and change in SUV(max) with outcomes.


METHODS
Consecutive patients with medically inoperable early-stage NSCLC and an FDG-PET/CT scan before (n=82) and 3 months after (n=62) SBRT.


RESULTS
Median follow up was 2 years. On univariate analysis baseline SUV(max) predicted for distant failure (p=0.0096), relapse free survival (RFS) (p=0.037) and local failure (p=0.044). On multivariate analysis baseline SUV(max) predicted for RFS (p=0.037). Baseline SUV(max) of above 5 was the most statistically significant cut off point for predicting distant failure (p=0.0002). Baseline SUV(max) ≥4.75 (median) was correlated with a higher risk of distant failure (p=0.012) and poorer RFS (p=0.04). Patients with a post-SBRT SUV(max) ≥2 and a reduction of <2.55 had a significantly higher rate of distant failure.


CONCLUSIONS
Pre-SBRT SUV(max) on FDG-PET/CT correlated most strongly with distant failure. A cut off of ≥5 was the most significant. Post-SBRT SUV(max) ≥2 and a reduction of <2.55 were associated with a higher risk of distant failure.
Princess Margaret Hospital, Toronto, Canada.
Katy
K
Clarke
Mojgan
M
Taremi
Max
M
Dahele
Marc
M
Freeman
Sharon
S
Fung
Kevin
K
Franks
Andrea
A
Bezjak
Anthony
A
Brade
John
J
Cho
Andrew
A
Hope
Alexander
A
Sun
D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D008297:Male; D064847:Multimodal Imaging; D015999:Multivariate Analysis; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D016634:Radiosurgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18