The therapeutic impact of 18F-FDG whole body PET

Abstract

Summary Aims: An explorative analysis of the diagnostic as well as therapeutic impact of 18F-FDG whole body PET on patients with various tumours in the setting of an university hospital radiation therapy was performed. Patients and methods: 222 FDG PET investigations (148 initial stagings, 74 restagings) in 176 patients with diverse tumour entities (37 lung carcinoma, 15 gastrointestinal tumours, 38 head and neck cancer, 30 lymphoma, 37 breast cancer, 19 sarcoma and 16 other carcinomas) were done. All PET scans were evaluated in an interdisciplinary approach and consecutively confirmed by other imaging modalities or biopsy. Unconfirmed PET findings were ignored. Proportions of verified PET findings, additional diagnostic information (diagnostic impact) and changes of the therapeutic concept intended and documented before PET with special emphasis on radiooncological decisions (therapeutic impact) were analysed. Results: 195/222 (88%) FDG-PET findings were verified, 104/222 (47%) FDG-PET scans yielded additional diagnostic information (38 distant, 30 additional metastasis, 11 local recurrencies, 10 primary tumours and 15 residual tumours after chemoptherapy). The results of 75/222 (34%) scans induced changes in cancer therapy and those of 58/222 (26%) scans induced modifications of radiotherapeutic treatment plan (esp. target volumes). Conclusion: 18F-FDG whole body PET is a valuable diagnostic tool for therapy planning in radiooncology with a high impact on therapeutic decisions in initial staging as well as in restaging. Especially in a curative setting it should be used for definition of target volumes.