Diagnostic and Prognostic Value of Using 18F-FDG PET/CT for the Evaluation of Bone Marrow Involvement in Peripheral T-Cell Lymphoma

PURPOSE: No study has analyzed a sizeable cohort that comprised solely peripheral T-cell lymphoma (PTCL) patients for the diagnostic and prognostic performance of F-FDG PET/CT for bone marrow (BM) involvement. This study aimed to investigate the utility of PET/CT for the identification of BM involvement and to explore its prognostic relevance in patients with PTCL. METHODS: Eighty-three consecutive patients with newly diagnosed PTCL were enrolled in this retrospective study. The diagnosis of BM involvement was confirmed on the basis of positive BM histology or disappearance of marrow abnormalities on follow-up PET/CT concurrently with a successful treatment response. RESULTS: Of 28 patients with confirmed BM involvement, BM biopsy (BMB) and PET/CT detected an involvement in 17 and 25 patients. Among 66 patients with negative BM histology, 11 patients had BM involvement detected by PET/CT and furthermore showed significantly shorter progression-free and overall survival than patients without BM involvement. We recategorized the International Prognostic Index (IPI) risk groups based on the presence of BM involvement using the combined assessment of iliac crest marrow biopsy histology and PET/CT (PET/BMB-based IPI). PET/BMB-based IPI tended to perform better than conventional BMB-based IPI. CONCLUSIONS: This study included the largest population of PTCL patients for PET/CT evaluation of BM involvement so far. PET/CT exhibited a higher sensitivity for BM involvement than BMB. Furthermore, BM assessment using PET/CT identified patients at high risk of disease progression and mortality among those with negative BM histology, suggesting that PET/CT may have a potential to improve existing prognostic strategies in PTCL.