Abstract for presentation at 38th Annual Scientific Meeting of the Australian and New Zealand Society of Nuclear Medicine 2008

Objective: To evaluate if FDG-PET, performed following salvage chemotherapy and prior to bone marrow transplant (BMT) predicted relapse post-BMT and to compare FDG-PET with CT.
Methods: We performed a retrospective review, matching data from the RMH Nuclear Medicine database with that from the Bone Marrow Transplant Service database. Patients with histologically proven lymphoma with FDG-PET and CT performed between the last cycle of salvage chemotherapy and BMT were included. FDG-PET was performed on a gamma camera in coincidence mode. PET studies were scored as positive if any abnormal uptake consistent with lymphoma was seen. CT studies were considered positive if lymph nodes > 1 cm in long axis or residual soft tissue masses were identified.
Results: 50 patients (40 Non-Hodgkin Lymphoma, 10 Hodgkin Lymphoma) were included. Of those patients with a positive PET pre-BMT, 12 of 20 (60%) relapsed (median DFS 124 days, range 13-450), 7 remained disease-free (median follow-up 1080 days) and there was 1 early post-transplant death. Of those with a negative PET, 4 of 30 (13%) relapsed (median DFS 119.5 days, range 70-194 days), while 26 of 30 (87%) remained in remission (median follow-up 975 days, range 29 to 1673 days). Sensitivity for the detection of relapse was 75% (PET) vs 78% (CT). Specificity was 77% (PET) vs 27% (CT).
Conclusions: Consistent with previously reported data, we demonstrated that FDG-PET performed pre-BMT can predict relapse post-transplant. PET has superior specificity for prediction of relapse when compared to CT.