Chemotherapy response evaluation with FDG-PET in patients with colorectal cancer

L. de Geus-Oei, H. van Laarhoven, E. Visser, R. Hermsen, B. van Hoorn, Y. Kamm, P. Krabbe, F. Corstens, C. Punt and W. Oyen

Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Feb, 2008



The aim of this prospective study was to evaluate the value of F-18-fluorodeoxyglucose-positron emission tomography (FDG-PET) for early assessment of chemotherapy response in patients with advanced colorectal cancer.Dynamic FDG-PET was carried out before and at 2 (n = 50) and 6 months (n = 19) after the start of treatment. Quantitative Patlak analysis [metabolic rate of glucose (MRGlu)] and a simplified method to measure glucose metabolism [standardized uptake value (SUV)] were evaluated. The predictive value of changes in glucose metabolism was assessed with Cox proportional regression analysis. Overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier estimates.There was an increase in the rates of death (P = 0.049 for DeltaMRGlu PET1-2; P = 0.017 for DeltaSUV PET1-2; P = 0.032 for DeltaMRGlu PET1-3; P = 0.048 for DeltaSUV PET1-3) and progression (P = 0.026 for DeltaMRGlu PET1-2; P = 0.035 for DeltaSUV PET1-2; P = 0.041 for DeltaMRGlu PET1-3; P = 0.081 for DeltaSUV PET1-3) associated with worse response as assessed by PET on Cox proportional regression analysis. The OS and PFS analysis showed a significant predictive value at broad ranges of DeltaMRGlu and DeltaSUV cut-off levels.The degree of chemotherapy-induced changes in tumor glucose metabolism is highly predictive for patient outcome. The use of FDG-PET for therapy monitoring seems clinically feasible since simplified methods (SUV) are sufficiently reliable.