Comparison of integrin αvβ3 expression and glucose metabolism in primary and metastatic lesions in cancer patients: A PET study using 18F-galacto-RGD and 18F-FDG

Abstract

The expression of αvβ3 and glucose metabolism are upregulated in many malignant lesions, and both are known to correlate with an aggressive phenotype. We evaluated whether assessment of αvβ3 expression and of glucose metabolism with PET using 18F-galacto-RGD and 18F-FDG provides complementary information in cancer patients. Methods: Eighteen patients with primary or metastatic cancer (non-small cell lung cancer [NSCLC], n = 10; renal cell carcinoma, n = 2; rectal cancer, n = 2; others, n = 4) were examined with PET using 18F-galacto-RGD and 18F-FDG. Standardized uptake values (SUVs) were derived by volume-of-interest analysis. 18F- Galacto-RGD and 18F-FDG PET results were compared using linear regression analysis for all lesions (n = 59; NSCLC, n = 39) and for primaries (n = 14) and metastases to bone (n = 11), liver (n = 10), and other organs (n = 24) separately. Results: The sensitivity of 18F-galacto-RGD PET compared with clinical staging was 76%. SUVs for 18F-FDG ranged from 1.3 to 23.2 (mean ± SD, 7.6 ± 4.9) and were significantly higher than SUVs for 18F-galacto-RGD (range, 0.3-6.8; mean ± SD, 2.7 ± 1.5; P = 0.001). There was no significant correlation between the SUVs for 18F-FDG and 18F-galacto-RGD for all lesions (r = 0.157; P = 0.235) or for primaries, osseous or soft-tissue metastases separately (P > 0.05). For the subgroup of lesions in NSCLC, there was a weak correlation between 18F-FDG and 18F-galacto-RGD uptake (r = 0.353; P = 0.028). Conclusion: Tracer uptake of 18F-galacto-RGD and 18F-FDG does not correlate closely in malignant lesions. Whereas 18F-FDG PET is more sensitive for tumor staging, 18F- galacto-RGD PET warrants further evaluation for planning and response evaluation of targeted molecular therapies with antiangiogenic or α vβ3-targeted drugs. Copyright © 2008 by the Society of Nuclear Medicine, Inc.