Is it sufficient to evaluate bone marrow involvement in newly diagnosed lymphomas using (18)F-FDG PET/CT and/or routine iliac crest biopsy? A new approach of PET/CT-guided targeted bone marrow biopsy

BACKGROUND: To investigate whether PET/CT-guided bone marrow biopsy adds complementary information for evaluation of bone marrow involvement (BMI) in newly diagnosed lymphomas. METHODS: Patients with newly diagnosed lymphomas that received both (18)F-FDG PET/CT and bone marrow biopsy (BMB) were included in this retrospective study. PET/CT classification of bone lesions was classified as isolated, multifocal (2 lesions or more), diffuse (homogeneous uptake of the entire axial skeleton), or negative. BMBs included PET/CT-guided targeted BMB and/or the routine unilateral iliac crest biopsy. Of 34 patients with focal lesions on PET/CT scan, 30 received both PET/CT-guided targeted BMB and iliac crest biopsy, and 4 patients received targeted biopsy without iliac crest biopsy. The final diagnosis of BMI depends on BMB results. RESULTS: A total of 299 patients with lymphomas were included. PET/CT classification of bone lesions was isolated (16/5.4%), multifocal (67/22.4%), diffuse (52/17.4%), and negative (164/54.8%). If only positive iliac crest biopsy was considered as the reference standard, the sensitivity of (18)F-FDG PET/CT for identifying focal and diffuse BMI was 48 and 56%, respectively, and the respective specificities were 70 and 83%. Three of 30 patients (10.0%) with focal lesions on PET/CT were confirmed to be false-positive by targeted BMB, and 25 of 30 patients (83.3%) with focal lesions on PET/CT were confirmed as false-negative by iliac crest biopsy. CONCLUSION: It is insufficient to evaluate BMI in newly diagnosed lymphomas using both (18)F-FDG PET/CT and routine iliac crest biopsy. (18)F-FDG PET/CT imaging should be performed before BMB. In focal bone lesions, PET/CT-guided targeted BMB may complement the results of possible false-positive PET/CT and false-negative iliac crest biopsy findings. However, in diffuse and negative lesions, iliac crest biopsy cannot be safely omitted.