18F-FAMT-PET is useful for the diagnosis of lymph node metastasis in operable esophageal squamous cell carcinoma.

ABSTRACT

BACKGROUND: The role and potential usefulness of positron emission tomography (PET) scanning in certain tumors has been widely investigated in recent years. (18)F-FAMT (L-[3-(18)F]-α-methyltyrosine) is an amino acid tracer for PET. This study investigated whether PET/CT with (18)F-FAMT provides additional information for preoperative diagnostic workup of esophageal squamous cell carcinoma compared with that obtained by (18)F-FDG (fluorodeoxyglucose) PET or CT. METHODS: PET/CT studies with (18)F-FAMT and (18)F-FDG were performed as a part of the preoperative workup in 21 patients with histologically confirmed esophageal squamous cell carcinoma. RESULTS: For the detection of primary esophageal cancer, (18)F-FAMT-PET exhibited a sensitivity of 76.2%, whereas the sensitivity for (18)F-FDG-PET was 90.5% (P = 0.214). (18)F-FAMT uptake in primary tumors showed significant correlation with depth of invasion (P = 0.005), lymph node metastasis (P = 0.045), stage (P = 0.031), and lymphatic invasion (P = 0.029). In the evaluation of individual lymph node groups, (18)F-FAMT-PET exhibited 18.2% sensitivity, 100% specificity, 71.9% accuracy, 100% positive predictive value, and 70.0% negative predictive value, compared with 24.2%, 93.7%, 69.8%, 66.6%, and 70.2%, respectively, for (18)F FDG-PET. CT exhibited 39.4% sensitivity, 85.7% specificity, 69.8% accuracy, 59.1% positive predictive value, and 73.0% negative predictive value. The specificity of (18)F-FAMT-PET is significantly higher than that of (18)F-FDG-PET (P = 0.042) and CT (P = 0.002). (18)F-FAMT-PET did not have any false-positive findings compared to those with (18)F-FDG-PET. CONCLUSIONS: Our findings suggest that the addition of (18)F-FAMT-PET to (18)F-FDG-PET and CT would permit more precise staging of esophageal cancer.