Positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose in oncology Part IIIb: Therapy response monitoring in colorectal and lung tumours,head and neck cancer, hepatocellular carcinoma and sarcoma

Positron emission tomography (PET) using 18 F-fluorodeoxyglucose (FBG) is c onsidered to be a very useful adjunct to anatomic imaging techniques and is now primarily used for oncological indications. These indications include diagnosis, staging: and therapy monitoring. In this review, we discuss the articles in which FBG-PET is clinically used for monitoring therapy in lung and colorectal tumours, head and neck cancer, sarcoma, and hepatocellular carcinoma, It is found that the amount of FDG uptake strongly correlates wi th response to therapy: a decrease in FDG uptake after therapy indicates a positive response to therapy. However, this conclusion is based on small nu mbers of patients. whereas the exact response mechanism is still unknown. M oreover, in these case series, the interval between tumour therapy and FBG- PET. as well as the method of quantification, SUV or tumour-to-non-tumour r atios, differ per study. Finally, dynamic imaging is a recommended techniqu e by some authors, but it is not a standard technique in clinical practice to evaluate tumour therapy. Therefore, further study is required which has to deal with these major issues before it is possible to draw definite conc lusions.