Positron emission tomography using F-18 fluorodeoxyglucose pre- and post-autologous stem cell transplant in non-Hodgkin's lymphoma.

Positron emission tomography (PET) utilizing fluorodeoxyglucose (FDG) has an ever-increasing role in the management of numerous malignancies. FDG PET in lymphoma is being incorporated into the response assessment in lymphoma as published by the Imaging Subcommittee of International Harmonization Project in Lymphoma. The exact role of FDG PET in non-Hodgkin's lymphoma (NHL) associated with autologous stem cell transplant (ASCT) is unclear. Numerous studies have identified pretransplant PET scans as being highly prognostic with regard to overall and PFS after ASCT. Many included a wide range of histologies, including Hodgkin's lymphoma and NHL. In studies with mixed histologies, PFS at 2 years has been improved by as much as 82% in patients with negative pre-ASCT PET scans. In studies incorporating only patients with NHL, improvements in failure-free survival have been reported as high as 43% for patients with negative pre-ASCT PET imaging. Limitations have included inclusion of many histologies, different reported time points, small retrospective studies and variation in the interpretation of a positive PET. Validation is ongoing in larger prospective trials. Future directions include the potential incorporation of post-ASCT therapy, such as radiation therapy or maintenance antibody therapy, for patients with positive pre-ASCT PET scans.