Abstract
BACKGROUND/AIMS: The role of [18F]-f luorodeoxyglucose positron emission tomography-computed tomography (PET/CT) in patients with diffuse large B-cell lymphoma (DLBCL) in first remission is unclear. METHODS: Medical costs within the first 3 years of treatment completion and clinical outcomes of 118 patients with DLBCL in first remission with and without surveillance PET/CT (PET/CT [+] group [n = 76] and PET/CT [-] group [n = 42], respectively) were retrospectively analyzed. RESULTS: In a propensity matched cohort with adjustment for International Prognostic Index risk and relapse, the PET/CT (+) group was shown to have similar medical costs as the PET/CT (-) group. Relapse-free survival (RFS) and overall survival (OS) were comparable between the two groups (median RFS not reached [NR] for both groups, p = 0.133; median OS NR, p = 0.542). Among 76 patients with surveillance PET/CT, 31 (40.8%) had findings suggestive of recurrence and 16 of these (51.6%) were later confirmed to have recurrent disease. Fifteen patients (48.4%) were confirmed to not have recurrence after follow-up CT or PET/CT evaluation (n = 10) and biopsy (n = 4). None of the patients with negative PET/CT findings had disease recurrence. Sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT for detection of recurrence were 1, 0.75, 0.52, and 1, respectively. CONCLUSION: Surveillance PET/CT resulted in similar clinical outcomes and medical costs compared to no surveillance PET/CT. Approximately half of patients with PET/CT findings of recurrence had no recurrence after follow-up imaging and biopsy, which would not have been carried out if PET/CT had not been performed in the first place.