Positron emission tomography using 18F-fluorodeoxyglucose for the evaluation of residual Hodgkin's disease mediastinal masses

Given its obvious prognostic implications, the correct interpretation of the significance of any residual mediastinal mass following Hodgkin's disease (HD) treatment keeps maintaining its paramount importance. In this respect, F-18-fluorodeoxyglucose positron emission tomography ( PET) is proving very effective for both active disease detection and relapse prediction. Twenty-nine consecutive HD patients, in whom computed tomography (CT) scan performed after therapy completion had documented a residual mediatinal mass of at least 2 cm, prospectively entered the study and underwent PET within 1 week from CT scan. With a median follow-up of 28 months from PET execution, no relapse was recorded among the 17 patients presenting with a negative PET. On the contrary, 9 of the 12 patients presenting with a positive PET relapsed/progressed within one year from PET execution. PET's negative and positive predictive values at 1 year were 100% and 75%, respectively. A negative PET seems to possibly exclude relapse in HD patient with a residual mediastinal mass. On the contrary, a positive PET result indicates a significantly higher risk of relapse. However, due to possible false positive results, a closer follow-up for all and a pathologic study in few selected patients is warranted.