18F-FMT Uptake Seen Within Primary Cancer on PET Helps Predict Outcome of Non–Small Cell Lung Cancer

Abstract

L-[3-(18)F]-alpha-methyl tyrosine ((18)F-FMT) is an amino-acid tracer for PET imaging. We evaluated the prognostic significance of (18)F-FMT PET in patients with non-small cell lung cancer. Ninety-eight patients (80 men and 18 women; age range, 42-82 y; median age, 69 y) with stage I-IV non-small cell lung cancer were enrolled in this study. They included 57 with adenocarcinoma, 31 with squamous cell carcinoma, 5 with large cell carcinoma, and 5 with other conditions. The median follow-up duration was 17.0 mo. A pair of PET studies with (18)F-FMT and (18)F-FDG was performed, and tracer uptake by the primary tumor was evaluated using the maximal standardized uptake value (SUV(max)). Overall survival and disease-free survival were calculated by the Kaplan-Meier method. The prognostic significance was assessed by univariate and multivariate analyses. The best discriminative SUV(max) cutoffs for (18)F-FMT and (18)F-FDG in the primary tumors were 1.6 and 11, respectively. In the univariate analysis, a high SUV(max) was significant in predicting poor overall survival for (18)F-FMT (P = 0.0129) and (18)F-FDG PET (P = 0.0481). According to histologic types, (18)F-FMT and (18)F-FDG uptake were a stronger prognostic predictor in adenocarcinoma than in nonadenocarcinomatous disease. Patients with a high SUV(max) for (18)F-FMT showed significantly worse disease-free survival rates than those with a low SUV(max), and multivariate analysis confirmed that a high SUV(max) for (18)F-FMT was an independent and significant factor in predicting a poor prognosis in patients with adenocarcinoma (P = 0.0191). Uptake of (18)F-FMT in primary tumors was an independent prognostic factor in patients with pulmonary adenocarcinoma.