18F-FDG-PET SUV AS A PROGNOSTIC MARKER OF INCREASING SIZE IN THYROID CANCER TUMORS

Objective: Positron emission tomography/computed tomography (PET/CT) scans with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (18F-FDG) are used in high-risk thyroid cancer patients to identify metastasis. The prognostic significance of increases in standardized uptake values (SUVs) has not been clearly defined. This pilot study investigated the correlation between SUV increases and subsequent changes in individual lesion size. Methods: A retrospective chart review of patients with histologically confirmed thyroid cancer who were monitored with serial 18F-FDG-PET/CT scans from 2008 to 2013 was performed. Forty-seven patients were selected for analysis. A mixed-effects statistical model was used after data normalization. Results: For a 10% increase in SUV, a 6% increase in tumor area was observed (P<.0001). Analysis on cube root-transformed data from serial scans was significant in 4 of 5 groups: scans 1 to 2 (P = .0001), scans 2 to 3 (P = .0005), scans 3 to 4 (P = .008), scans 4 to 5 (P = .66), and overall (P<...