Use of PET/CT for staging and radiation therapy planning in patients with non-small cell lung cancer.

Positron emission tomography (PET) and more recently PET/computed tomography (CT) scanning represent major advances in the imaging of lung cancer and have an especially high impact on the management of patients who are candidates for potentially curative or "radical" radiotherapy (RT). This article reviews the current status of PET and PET/CT for staging patients before RT and considers the use of PET and PET/CT images for target volume definition. The relevant literature on the use of PET for staging lung cancer is reviewed and placed in the context of patients who are candidates for RT. Research that specifically considers the use of PET for RT planning is considered critically and some promising areas for future research are discussed. The available literature is almost exclusively devoted to non small cell lung cancer (NSCLC) with few relevant studies of small cell lung cancer (SCLC). The primary PET radiopharmaceutical shown to have value for staging and RT planning is 18F-fluorodeoxyglucose (FDG). In prospective studies where PET imaging was used to stage radical RT candidates, 25-30% of patients were excluded from radical therapy because of PET detected advanced disease. In all studies where "PET-assisted" and conventional target or treatment volumes were compared, there were major differences between PET and conventional volumes. Because PET-assisted staging is proven to be significantly more accurate than conventional staging and because all studies show major differences between PET-assisted and conventional treatment volumes in NSCLC, routine use of PET/CT for RT planning is recommended.