What is the utility of FDG PET for response assessment in cancer patients?
FDG PET is useful for accurate early quantitative assessment of tumor response to therapy and provides the opportunity to change treatment promptly in the case of a nonresponse, thereby ameliorating or preventing unnecessary side effects while maximizing the chance for an improved outcome. Early response assessment, days to weeks after the initiation of therapy, is often possible because changes in tumor metabolism precede changes in tumor size. In general, a reduction in tumor FDG uptake after therapy is more likely to be associated with a histopathologic response and improved patient survival than is a lack of change
