Prognostic Value of Bone Marrow FDG Uptake Pattern of PET/CT in Newly Diagnosed Diffuse Large B-cell Lymphoma

Abstract

Purpose: The value of ¹⁸F-fluorodeoxyglucose positron emission tomography /computed tomography (¹⁸F-FDG PET/CT) in assessing bone marrow involvement (BMI) of lymphoma remains controversial. The present study aims to evaluate the prognostic meaning of bone marrow FDG uptake pattern in PET/CT of newly diagnosed diffuse large B-cell lymphoma (DLBCL) patients. Materials and Methods: 193 newly diagnosed DLBCL patients were retrospectively analyzed. All patients received 6-8 cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP). The type of BM FDG uptake pattern was recorded by two blinded reviewers independently. The relationship between clinicopathologic features and BM patterns was analyzed. The prognostic value of different BM patterns was evaluated by Log-rank test and Cox-regression analysis. Results: Out of 193 patients, 28 (15%) patients had focal BM FDG uptake higher than liver (fPET+), 18 (9%) patients showed diffuse BM uptake higher than liver (dPET+) and 147 (76%) patients had normal BM uptake (lower than liver) (nPET). BMB positive was found in 35.7% (10/28) of fPET+ patients, in 16.7% (3/18) of dPET+ patients and in 0.7% (1/147) of nPET patients. Diffuse BM pattern was associated with lower hemoglobin level and a trend of higher erythrocyte sedimentation rate (ESR). dPET+ patients had similar 3y-progression-free survival (3y-PFS) and 3y-overall survival (3y-OS) compared with nPET patients (80.5% vs 81.5%, p=0.701; 94.1% vs 90.6%, p=0.809, respectively), while fPET+ patients had worse 3y-PFS and 3y-OS compared with fPET- patients (32.7% vs 81.4%, p<0.001; 69.4% vs 90.9%, p=0.003, respectively). Multivariate analysis showed fPET+ (HR=2.270, p=0.025) and stage III/IV (HR=4.909, p=0.026) were independent predictors for PFS, but no factors were independently predictive for OS. Conclusion: PET/CT-directed BM patterns are meaningful in predicting prognosis of newly diagnosed DLBCL patients. Focal BM pattern is an independent predictor for PFS.

Keywords: DLBCL; FDG uptake pattern; PET/CT; bone marrow; prognosis.

Figure 1

MIP images of focal (A), diffuse (B) and normal (C) FDG uptake patterns of bone marrow in DLBCL.

Figure 2

The case contribution of BMI assessed by PET/CT-based BM pattern and BMB

Figure 3

Comparison of SUVmax on BM between different groups.

Figure 4

PFS Kaplan Meier Curves of DLBCL patients in groups. A. Comparison of PFS between different BM patterns. 3y-PFS of dPET+ vs nPET was 80.5% vs 81.5%, p=0.701; 3y-PFS of fPET+ vs nPET was 32.7% vs 81.5%, p<0.001. B. Comparison of PFS between focal pattern and non-focal pattern. 3y-PFS of fPET+ vs fPET- was 32.7% vs 81.4%, p<0.001. C. Comparison of PFS between different BM patterns in BMB negative patients. 3y-PFS of dPET+ vs nPET was 90% vs 81.4%, p=0.618; 3y-PFS of fPET+ vs nPET was 0% vs 81.4%, p<0.001. D. Comparison of PFS between focal pattern and non-focal pattern in BMB negative patients. 3y-PFS of fPET+ vs fPET- was 0% vs 82.2%, p<0.001.

Figure 5

OS Kaplan Meier Curves of DLBCL patients in groups. A. Comparison of OS between different BM patterns. 3y-OS of dPET+ vs nPET was 94.1% vs 90.6%, p=0.809; 3y-OS of fPET+ vs nPET was 69.4% vs 90.6%, p<0.001. B. Comparison of OS between focal pattern and non-focal pattern. 3y-OS of fPET+ vs fPET- was 69.4% vs 90.9%, p=0.003. C. Comparison of OS between different BM patterns in BMB negative patients. 3y-OS of dPET+ vs nPET was 100% vs 90.6%, p=0.300; 3y-OS of fPET+ vs nPET was 76.9% vs 90.6%, p=0.037. D. Comparison of OS between focal pattern and non-focal pattern in BMB negative patients. 3y-OS of fPET+ vs fPET- was 76.9% vs 91.3%, p=0.023.

Figure 6

PFS and OS Kaplan Meier Curves between BMB positive and BMB negative patients. A. Comparison of PFS between BMB+ and BMB- patients. 3y-PFS of BMB+ vs BMB- was 60.6% vs 76.1%, p=0.205. B. Comparison of OS between BMB+ and BMB- patients. 3y-OS of BMB+ vs BMB- was 61% vs 89.8%, p=0.008.