Study objectives: To determine and compare the values of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) and CT for predicting clinical outcome of patients with aggressive lymphoma undergoing salvage cytoreductive chemotherapy followed by high-dose chemotherapy and autologous stem-cell transplantation (ASCT).
Patients and methods: Forty-three patients with lymphoma who underwent ASCT with FDG-PET evaluation were studied. Group 1 (n = 20) patients (6 patients with Hodgkin disease [HD], and 14 patients with non-Hodgkin lymphoma [NHL]) underwent PET 2 to 5 weeks after initiation of salvage chemotherapy, prior to ASCT. Group 2 (n = 23) patients (6 patients with HD, and 17 patients with NHL) underwent PET within a median interval of 2.4 months (range, 2 to 6 months) after ASCT.
Measurements and results: Study end points were complete remission, relapse, or death. In group 1, 8 of 20 patients (40%) were disease free after a median follow-up of 13.3 months; 12 patients relapsed or died. PET findings were true-negative in 7 of 8 patients and true-positive in 11 of 12 patients who relapsed after ASCT. In group 2, 9 of 23 patients (39%) were disease free after a median follow-up of 16.5-months; 14 patients relapsed. PET findings were true-negative in 8 of 9 patients and true-positive in 13 of 14 patients who relapsed. Positive and negative predictive values of PET were 92% and 88% (group 1) and 93% and 89% (group 2), respectively. Predictive accuracy values of PET were 90% and 91% for group 1 and group 2, respectively, vs 58% and 67% for CT (p < 0.05).
Conclusions: PET findings but not CT results were strongly correlated with disease-free survival (p < 0.01). Our results show that FDG-PET can be used to predict the post-ASCT outcome of lymphoma patients with high accuracy.