Use of 18F-FDG PET/CT as a predictive biomarker of outcome in patients with head-and-neck non-squamous cell carcinoma.

OBJECTIVE: The purpose of this article is to establish whether pretreatment (18)F-FDG uptake predicts disease-free survival (DFS) and overall survival in patients with head-and-neck non-squamous cell carcinoma (SCC). MATERIALS AND METHODS: Eighteen patients (six women and 12 men; mean [± SD] age at diagnosis, 57.89 ± 13.54 years) with head-and-neck non-SCC were included. Tumor FDG uptake was measured by the maximum standardized uptake value (SUV(max)) and was corrected for background liver FDG uptake to derive the corrected SUV(max). Receiver operating characteristic analyses were used to predict the optimal corrected SUV(max) cutoffs for respective outcomes of DFS (i.e., absence of recurrence) and death. RESULTS: The mean corrected SUV(max) of the 18 head-and-neck tumors was 5.63 ± 3.94 (range, 1.14-14.29). The optimal corrected SUV(max) cutoff for predicting DFS and overall survival was 5.79. DFS and overall survival were significantly higher among patients with corrected SUV(max) < 6 than among patients with corrected SUV(max) ≥ 6. The mean DFS for patients with corrected SUV(max) < 6 was 25.7 ± 11.14 months, and the mean DFS for patients with corrected SUV(max) ≥ 6 was 7.88 ± 7.1 months (p < 0.018). Among patients with corrected SUV(max) < 6, none died, and the mean length of follow-up for this group was 35.2 ± 9.96 months. All of the patients who died had corrected SUV(max) ≥ 6, and the overall survival for this group was 13.28 ± 12.89 months (p < 0.001). CONCLUSION: FDG uptake, as measured by corrected SUV(max), may be a predictive imaging biomarker for DFS and overall survival in patients with head-and-neck non-SCC.

Squamous cell carcinoma of the palatine tonsils: FDG standardized uptake value ratio as a biomarker to differentiate tonsillar carcinoma from physiologic uptake.

PURPOSE: 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). MATERIALS AND 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. CONCLUSION: The SUV(max) ratio represents an accurate imaging biomarker for differentiating tonsillar SCC from physiologic (18)F-FDG uptake.