AJR Am J Roentgenol. 2020 Aug 19. doi: 10.2214/AJR.20.24036. Online ahead of print.
Background: Several guidelines recommend body imaging for initial work-up in patients with suspected primary central nervous system (CNS) lymphoma to exclude subclinical systemic involvement. However, the diagnostic yield of body CT (contrast-enhanced CT of the chest, abdomen, and pelvis) and whole-body FDG-PET/CT for the evaluation of subclinical systemic lymphoma has not been systematically evaluated. Objective: To investigate and compare the diagnostic yield of body CT and whole-body FDG-PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. Evidence Acquisition: A systematic search of MEDLINE and EMBASE through July 5, 2020 was conducted to identify studies evaluating the diagnostic yield of body CT or whole-body FDG-PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. Pooled estimates of the diagnostic yield of both imaging modalities were calculated using DerSimonian-Laird random effects model. False referral rate and rate of incidental secondary malignancy were also pooled. Evidence Synthesis: Nine original articles with 1040 patients were included. In detecting subclinical systemic lymphoma, the pooled diagnostic yields of body CT and whole-body FDG-PET/CT were 2.5% (95% confidence interval [CI], 1.5-3.9%) and 4.9% (95% CI, 2.8-8.5%), respectively. In the subgroup analysis, the diagnostic yield of whole-body FDG-PET/CT was significantly higher than that of body CT (P = 0.03). Four studies reported changes in the management plan: R-CHOP regimen with or without radiation therapy was added if extracranial lymphoma involvement was detected by body CT or whole-body FDG-PET/CT. The pooled false referral rate of whole-body FDG-PET/CT was 5.3% (95% CI, 2.2-12.0%). The pooled rate of incidental secondary malignancy of whole-body FDG-PET/CT was 3.1% (95% CI, 1.7-5.6%). Conclusion: Body imaging should be used in the initial work-up of patients with suspected primary CNS lymphoma to exclude systemic involvement. Whole-body FDG-PET/CT may be a better alternative to body CT. Clinical Impact: Our results support the current National Comprehensive Cancer Network (NCCN) guideline for the use of body imaging in patients with suspected primary CNS lymphoma to exclude subclinical systemic involvement.