Pre-treatment 18f-FDG PET/CT for Assessing and Predicting Bone Marrow Involvement in Patients with Newly Diagnosed Peripheral T-Cell Lymphoma

Abstract

Objective: To explore the value of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in assessing and predicting bone marrow involvement (BMI) in patients with newly diagnosed peripheral T-cell lymphoma (PTCL) prior to treatment. Methods: This retrospective study included 201 eligible patients of PTCL who received bone marrow biopsy (BMB) and PET/CT between January 2017 and December 2022. Extra subgroup analysis was designed considering the variation of avidity of FDG in different distinct entities. The status of bone marrow (BM) by PET was assessed using a visual examination and a quantitative index (the highest SUV of BM divided by the mean SUV of the liver [M/L]). Prognostic value of BM findings was also evaluated regarding progression free survival (PFS) and overall survival (OS). Results: The sensitivity and specificity of PET/CT for patients with confirmed PTCL by BMB were 43.2% and 90.2%, respectively. As for subgroup analysis, the kappa value reflecting the agreement between BMB and visual analysis in angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma (ALCL) as well as nodal T-follicular helper (TFH) cell lymphoma (PTCL-TFH) was 0.315, 0.307, 0.426 and 0.581, respectively. (Give the number of cases in each lymphoma group) PET score was an independent factor for PFS (P =0.011) but not for OS (P =0.840). In addition, 25 patients with stage I to II disease had no evidence of BMI by either PET/CT or BMB. Image-guided biopsy was also recommended when PET/CT showed a focal FDG uptake outside the iliac crest. Quantitative analysis revealed the differences in the two-level of M/L; however, they were not statistically significant for both PFS and OS (P =0.246 and P =0.227). Conclusion: PET/CT has a complementary role in assessing BMI and prognosis in PTCL patients.