Squamous cell carcinoma of the palatine tonsils: FDG standardized uptake value ratio as a biomarker to differentiate tonsillar carcinoma from physiologic uptake.
OBJECTIVE
To quantify fluorine 18 ((18)F) fluorodeoxyglucose (FDG) uptake in the palatine tonsils to identify a sensitive and specific metric for distinguishing physiologic asymmetric uptake from squamous cell carcinoma (SCC).


METHODS
This HIPAA-compliant retrospective study was approved by institutional review board. Informed consent requirements were waived. Twenty-six patients (seven female, 19 male; mean age, 53.46 years + or - 10.45 [standard deviation]) with tonsillar SCC were included. Twenty-six patients (seven female, 19 male; mean age, 61.77 years + or - 10.12) with head and neck carcinomas not involving the tonsils were included as control subjects. Tonsil standardized uptake values (SUVs) were measured bilaterally in each group. Independent-samples t test was used to compare mean SUVs, and Pearson correlation was used to evaluate association of FDG uptake between tonsils within control subjects.


RESULTS
The mean maximum SUV (SUV(max)) of tonsil tumors was 9.36 + or - 4.54, which was significantly higher than that of contralateral cancer-free tonsils (2.54 + or - 0.88; P < .0001) and tonsils in control subjects (2.98 + or - 1.08; P < .0001). In patients with tonsillar cancer, the mean difference in SUV(max) between tonsils was 10.43 + or - 7.07, which was significantly greater than that in control subjects (0.62 + or - 0.54; P < .0001). The mean SUV(max) ratio between tonsils in patients with carcinoma was 3.79 + or - 1.69, which was threefold higher than in control subjects (1.18 + or - 0.13; P < .0001). For receiver operating characteristic analysis using SUV(max) ratio to differentiate benign uptake from SCC, the area under the curve was 1.00 (95% confidence interval: 1.00, 1.00). A cutoff ratio of 1.48 had 100% sensitivity and specificity.


CONCLUSIONS
The SUV(max) ratio represents an accurate imaging biomarker for differentiating tonsillar SCC from physiologic (18)F-FDG uptake.
Davison
Jessica M
JM
Department of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, Level 3, Boston, MA 02118, USA.
Ozonoff
Al
A
Imsande
Heather M
HM
Grillone
Gregory A
GA
Subramaniam
Rathan M
RM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism; D003287:Contrast Media / Q000493:pharmacokinetics; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014066:Palatine Tonsil / Q000000981:diagnostic imaging* / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D036542:Tomography, Spiral Computed; D014067:Tonsillar Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D014283:Triiodobenzoic Acids / Q000493:pharmacokinetics
D015415:Biomarkers; D003287:Contrast Media; D019275:Radiopharmaceuticals; D014283:Triiodobenzoic Acids; D019788:Fluorodeoxyglucose F18; C054871:ioversol