Prognostic analysis of ΔSUVmax%, Deauville and MYC gene rearrangement in early chemotherapy with diffuse large B-cell lymphoma

Objectives: To evaluate the prognostic value of the SUVmax decrease proportion (ΔSUVmax%) and Deauville 5-point scale(D-5PS) on PET/CT imaging and the MYC gene rearrangement during early chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL).

Methods: Sixty primary diagnosed patients (29 males, 31 females, average age of 51±2 (12-81) years) with pathologically confirmed DLBCL were analyzed. ¹⁸F-FDG PET/CT was performed before and after 1 or 2 cycles of chemotherapy (30 patients each). The region of interest (ROI) was drawn, and the ΔSUVmax% was calculated. Patients were evaluated using the D-5PS. Fluorescence in situ hybridization (FISH) was employed to detect the MYC gene. The optimum cutoff value of ΔSUVmax% according to the ROC analysis, the D-5PS in patients with scores <5 and those with scores = 5, then the Kaplan-Meier analysis was analyzed. χ² test or Fisher exact probabilitu test, Spearman correlation analysis and effectiveness evaluation of diagnostic test were used.

Results: The optimum cutoff value of ΔSUVmax% was 62.5%, corresponding to D-5PS scores of 5. The sensitivity, specificity and accuracy of ΔSUVmax% and D-5PS were 66.7% vs 76.5%, 97.4% vs 95.3%, 86.7% vs 90%, respectively. The sensitivity, specificity, accuracy and the area of under the ROC curve of ΔSUVmax% between 1 cycle and 2 cycles were 80% vs 54.5%, 95% vs 100%, 90% vs 83.3%, 0.921 vs 0.896, respectively. No significant difference was found in ΔSUVmax% and D-5PS of early chemotherapy, in ΔSUVmax% between 1 cycle and 2 cycles of chemotherapy (all P>0.05). ΔSUVmax% was negatively correlated with the MYC gene and D-5PS (r = -0.570, -0.767, both P<0.001). D-5PS was positively correlated with the MYC gene (r = 0.638, P<0.001) Patients with ΔSUVmax%≥62.5% (n=39), D-5PS<5 (n=43) or MYC (-) (n=42) showed better and longer progression-free survival (PFS) (χ²=33.674, 39.458, and 61.694, respectively, all P<0.001). Patients with ΔSUVmax%<62.5% or D-5PS=5 together with MYC (+) displayed the worst PFS (χ²=67.403 and 66.695, respectively, both P<0.001). Conclusion: ¹⁸F-FDG PET/CT imaging during the early phase of chemotherapy and the MYC gene have better predictive values for DLBCL prognosis. There is a better correlation between ΔSUVmax%, D-5PS and MYC gene rearrangement. Key words: diffuse large B-cell lymphoma; chemotherapy; MYC gene rearrangement; ¹⁸F-FDG PET/CT; prognosis