Purpose: To retrospectively determine the sensitivity and specificity of co-registered fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with Hodgkin lymphoma after first-line therapy, with use of clinical follow-up or biopsy results as the reference standard.
Materials and methods: Informed consent was obtained for imaging and included consent to use patient data for research purposes. Institutional review board approval was obtained. Between May 2001 and July 2005, the data for all patients (n=66) at the authors' institution with proved Hodgkin lymphoma after first-line therapy were retrospectively reviewed. PET/CT scans were evaluated for the presence of abnormal FDG uptake and residual masses after the end of treatment and at further follow-up. All patients with pathologic FDG lesions underwent surgical biopsy for histopathologic confirmation. All patients with negative PET/CT scans at follow-up were evaluated for disease-free survival.
Results: An FDG-avid lesion was detected at PET/CT in 27 of the 66 patients (mean age +/- standard deviation, 33.0 years +/- 12.2). Recurrence of Hodgkin lymphoma was confirmed with biopsy in 23 of the 27 patients. The mean maximum standardized uptake value (SUV) of the histopathologically proved lesions was 7.32 (+/-2.01). Four patients had false-positive findings at PET/CT: Biopsy revealed only inflammatory changes, and the mean maximum SUV was 7.30 (+/-2.53). Thirty-nine patients (mean age, 36.7 years +/- 10.8) did not have FDG-avid lesions and remained free of disease after a mean clinical follow-up of 26.2 months (+/-12.5) (specificity, 91% [39 of 43 patients]; sensitivity, 100% [23 of 23 patients]). The presence of bulky disease (>5 cm) after the end of treatment was a significant predictor of recurrent disease (P<.05).
Conclusion: The authors conclude that FDG PET/CT can help exclude persistent and/or recurrent Hodgkin lymphoma after first-line therapy. Because of the false-positive results and the toxicity of salvage chemotherapy, including high-dose chemotherapy with autologous stem cell support, biopsy of the FDG-avid lesion is still needed.
(c) RSNA, 2007.