Aim: The purpose of the present paper is to assess clinical value of PET in oncology on the basis of published studies.
Methods: Clinical value of PET in oncology was evaluated by a panel of recognized experts in the framework of an interdisciplinary consensus conference. On the basis of PET studies, well documented in the international literature, the value of PET for solving clinical questions was classified according to the following categories (classes 1a, 1b, 2a, 2b, 3): "appropriate" (1a), "mostly acceptable" (1b), "helpful" (2a), "value as yet unknown" (2b), "useless" (3).
Results: 2-fluorodeoxyglucose (FDG) acts as the radiopharmaceutical of choice for PET in clinical oncology. PET is indicated (1a) for diagnosing relapse in high grade glioma (FDG) or low grade glioma (C-11 methionine or F-18 fluorotyrosine), differential diagnosis of solitary peripheral pulmonary nodules in high risk patients and for diagnosis of pancreatic carcinoma. PET may be clinically used (1b): In "low-grade" glioma, search for unknown primary in head and neck tumors, suspicion of relapse in non-small cell bronchial carcinoma (NSCBC) and colorectal carcinoma, lymphnode staging in NSCBC, pancreatic carcinoma, muscle invasive bladder carcinoma and testicular cancer. Staging of Hodgkin's disease (HD, stage I/II vs III), early therapy control in patients with a residual mass or suspicion of relapse in HD and in high grade NHL, lymph node staging and search for distant metastases in malignant melanoma (Breslow > 1.5 mm), search for lymph node or distant metastases in differentiated thyroid cancer with elevated hTG and a negative radioiodide whole body scan. Many further indications are emerging, but are not yet sufficiently well documented in the literature. For most indications beside scientific studies, an individual cost benefit utility evaluation by the responsible physician is recommended.
Conclusion: Metabolic imaging of PET provides for many principle advantages compared to conventional anatomically based cross sectional imaging. For routine use in oncology a detailed assessment of specific efficiency of PET is indicated.