[Diagnostic and Prognostic Value of 18F-FDG PET/CT in Bone Marrow Infiltration of Newly Diagnosed Diffuse Large B-Cell Lymphoma].

ABSTRACT

OBJECTIVE: To explore the diagnostic value of 18F-FDG PET/CT in bone marrow infiltration (BMI) of newly diagnosed diffuse large B-cell lymphoma (DLBCL), compared with the results of bone marrow biopsy (BMB) and investigate whether the BMI diagnosed by 18F-FDG PET/CT and other factors have independent prognostic values. METHODS: Ninety-four newly diagnosed DLBCL patients who underwent PET/CT in Clinical Medical College of Shanghai General Hospital of Nanjing Medical University were included. BMB was performed within 2 weeks before or after PET/CT, and standardized treatment was performed after PET/CT. The manifestations of bone marrow (BM) FDG uptake were recorded. The diagnostic criteria of BMI were BMB positive or focal BM FDG uptake confirmed by imaging follow-up. The relationship between clinical features and BM FDG uptake and the values of PET/CT and BMB in the diagnosis of BMI was analyzed. The progression-free survival (PFS) was analyzed by Kaplan-Meier survival curves, log-rank test was used to compare PFS rate, and Cox regression model was used to analyze the independent risk factors affecting PFS. RESULTS: Among 94 DLBCL patients, 34 patients showed focal BM uptake (fPET), 7 patients showed super BM uptake (sBMU), 11 patients showed diffuse homogenous uptake higher than liver (dPET), and the other 42 patients had normal BM uptake (nPET) (lower than liver). BMB positive was found in all sBMU patients, in 20.6%(7/34) of fPET patients, and in 27.3% (3/11) of dPET patients. All nPET patients had negative BMB results. dPET patients were associated with lower hemoglobin level and leukocyte count compared with nPET group (P < 0.001, P =0.026). Compared with fPET patients, sBMU patients were more likely to have B symptoms and elevated lactate dehydrogenase (LDH). A total of 44 patients were diagnosed BMI, including 17 cases with BMB+. The sensitivity and specificity of BMB in the diagnosis of BMI was 38.6% (17/44) and 100% (50/50), respectively. Using fPET and sBMU as criteria of PET BMI, the diagnostic sensitivity and specificity of PET/CT was 93.2% (41/44) and 100% (50/50), respectively. Kaplan-Meier analysis showed that there was no significant difference in 2-year PFS rate between nPET and dPET patients (P >0.05), while sBMU patients had lower 2-year PFS rate compared with fPET patients (P < 0.001). Multivariate analysis showed that higher Ann Arbor stage (HR=9.010, P =0.04) and sBMU (HR=3.964, P =0.002) were independent risk factors affecting PFS. CONCLUSIONS: Increased BM FDG uptake of DLBCL can be manifested as dPET, fPET and sBMU. fPET and sBMU can replace BMB to diagnose BMI. Although dPET cannot completely exclude the possibility of BMI, it does not affect the prognosis, so it can be diagnosed as PET BMI negative. sBMU is an independent prognostic risk factor.