Cancer Treatment Response Assessment/Prediction

摘要

Positron emission tomographic (PET) imaging with the glucose analog fluorine 18 fluorodeoxyglucose (FDG) has been evaluated in numerous studies to monitor tumor response in patients undergoing chemo- and chemoradiotherapy. The clinical value of FDG PET for differentiation of residual or recurrent viable tumor and therapy-induced fibrosis or scar tissue has been documented for malignant lymphomas and various solid tumors. Furthermore, there are now several reports suggesting that quantitative assessment of therapy-induced changes in tumor FDG uptake may allow prediction of tumor response and patient outcome very early in the course of therapy. In nonresponding patients, treatment may be adjusted according to the individual chemo- and radiosensitivity of the tumor tissue. This indicates that FDG PET has an enormous potential to "personalize" treatment and to reduce the side effects and costs of ineffective therapy. Since new "targeted" forms of anticancer therapy (eg, protein kinase inhibitors) are expected to be effective only in a relatively small subset of patients, early prediction of tumor response by FDG PET is expected to become even more important for clinical trials and patient management in the future. The use of in-line PET/computed tomography (PET/CT) instead of stand-alone PET for treatment monitoring poses some methodological challenges for the quantitative analysis of PET scans but also provides the opportunity to integrate morphological and functional information. This may allow definition of new parameters for assessment of tumor response, but it will also facilitate the use of PET imaging in research studies as well as in clinical practice.