The Utility of FDG-PET for Managing Patients with Malignant Lymphoma: Analysis of Data from a Single Cancer Center

Objective F-18-fluorodeoxyglucose (FDG) positron-emission tomography (PET) has been widely applied to malignant lymphoma both for initial staging and response evaluation. The objective is to compare the efficacy of the less common, but more easily implemented modality, CT, With that of FDG. Methods We retrospectively reviewed consecutive patients diagnosed With malignant lymphoma in our hospital between October 2002 and March 2006, and compared the efficacy of FDG-PET and CT. The standard reference was defined by the pathology and clinical course of patients followed for more than 3 months. Results Thirty-three cases for staging and 62 cases for response evaluation after treatment were included. We calculated the sensitivity and specificity of each modality. The accuracy of the diagnostic modality was evaluated using receiver operating characteristic (ROC) analysis. The sensitivity and specificity of the initial staging were 87% and 100% on CT evaluation and 87% and 100% on FDG-PET, respectively. Sensitivity and specificity of the re-staging were 81% and 78% on CT evaluation and 82% and 97% on FDG-PET, respectively. The diagnostic accuracy of FDG-PET was comparable With that of CT both in initial staging and response evaluation. The maximum standardized uptake value was not associated with patient survival. In subgroup analysis, a tendency of lower sensitivity in the initial staging was found in FDG-PET for follicular lymphoma and CT for diffuse large B-cell lymphoma. Conclusion Although different staging procedures appear better suited to certain subtypes of lymphoma, in general CT imaging might be as useful as FDG-PET in initial staging in selected patients.