Abstract
BACKGROUND: In non-small cell lung cancer (NSCLC), (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) uptake determined by PET and presence of circulating tumor cells (CTCs) in the peripheral blood independently predict outcomes. For (18)F-FDG PET/CT staging interpretation, standardized uptake values (SUV(max/avg)) are routinely used in clinical reporting. The goal was to investigate whether (18)F-FDG uptake measured by SUV(max/avg), but also measures of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) (MTV × SUV(avg)), are associated with CTCs. METHODS: Prospectively, 7.5 mL blood was drawn from NSCLC patients at the time of staging 18F-FDG PET/CT and from healthy control subjects. CTCs were identified by immunofluorescent staining (CK8/18/19(pos)/EpCAM(pos)/CD45(neg)/DAPI(pos) nucleus). (18)F-FDG PET/CTs were analyzed for SUV(max), SUV(avg), MTV, and TLG. RESULTS: In 16 NSCLC patients with stage I-IIIA, MTV and TLG, in contrast to SUV(max) and SUV(avg), were positively associated with CTCs (linear regression analysis). No CTCs were detectable in 20 healthy control subjects. CONCLUSIONS: This pilot study demonstrates that (18)F-FDG PET/CT TLG correlates with CTCs in NSCLC patients without distant metastases. TLG might be a more appropriate marker for hematogenous micrometastatic potential than SUVs.