Evaluation of thoracic tumors with 18F‐FMT and 18F‐FDG PET‐CT: A clinicopathological study

Abstract

L‐[3‐¹⁸F]‐α‐methyltyrosine (¹⁸F‐FMT) is an aminoacid tracer for positron emission tomography (PET). The aim of this study was to determine whether PET‐CT with ¹⁸F‐FMT provides additional information for the preoperative diagnostic workup as compared with ¹⁸F‐FDG PET. PET‐CT studies with ¹⁸F‐FMT and ¹⁸F‐FDG were performed as a part of the preoperative workup in 36 patients with histologically confirmed bronchial carcinoma, 6 patients with benign lesions and a patient with atypical carcinoid. Expression of L‐type amino acid transporter 1 (LAT1), CD98, Ki‐67 labeling index, VEGF, CD31 and CD34 of the resected tumors were analyzed by immunohistochemical staining, and correlated with the uptake of PET tracers. For the detection of pulmonary malignant tumors, ¹⁸F‐FMT PET exhibited a sensitivity of 84% whereas the sensitivity for ¹⁸F‐FDG PET was 89% (p = 0.736). ¹⁸F‐FMT PET‐CT and ¹⁸F‐FDG PET‐CT agreed with pathological staging in 85 and 68%, respectively (p = 0.151). ¹⁸F‐FMT uptake was closely correlated with LAT1, CD98, cell proliferation and angiogenesis. The specificity of ¹⁸F‐FMT PET for diagnosing thoracic tumors was higher than that of ¹⁸F‐FDG PET. Our results suggest that coexpression of LAT1 and CD98 in addition to cell proliferation and angiogenesis is relavant for the progression and metastasis of lung cancer.