Objective: To evaluate the application of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to the staging and detecting residual masses of lymphoma.
Methods: The clinical data of 179 patients with lymphoma were analyzed retrospectively. The results of FDG-PET, computed tomography (CT) and bone marrow biopsy (BMB) were compared for detection of lymph node/extranodal lymphoid tissue and bone marrow infiltration. Therapeutic efficiency was assessed by International Workshop Criteria (IWC) and Revised Integrated International Workshop Criteria (IWC + PET).
Results: In the detection of 286 disease focuses in 98 patients before chemotherapy, the sensitivities of FDG-PET and CT were 73% and 70% (P < 0.01) in detecting nodal focus,and 87% and 45% (P < 0.01) in detecting extranodal lymphoma respectively. In detection of 104 lesions in 81 patients after chemotherapy,the sensitivities of FDG-PET and CT were 81% and 55% respectively (P < 0.01), and the specificities were 68% and 33%, respectively (P < 0.01) in detecting residual masses. According to IWC criteria, 33 patients achieved complete response/unconfirmed complete response (CR/CRu) , and 8 (24%) relapsed. Patients with PET-positive residual masses had a relapse rate of 40%, whereas only 21% of those with no such masses relapsed. Based on IWC + PET criteria, 25 patients achieved CR, with a relapse rate of 20%. Both FDG-PET and BMB produced positive results in 133/179 (74%) patients. Twenty-two patients with positive FDG-PET results were not detected by BMB. The sensitivities and specificities of FDG-PET for BM infiltration were 52% and 83%, respectively.
Conclusions: FDG-PET is a high sensitive and specific technique in staging and detecting residual masses of lymphoma.