Prognostic significance of interim ¹⁸F-FDG PET/CT SUV reduction associated with Ki67 in patients with diffuse large B-cell lymphoma

o detect the prognostic significance of interim 18F-FDG PET/CT SUV (standard uptake value) reduction (ΔSUVmax) associated with Ki67 in patients with diffuse large B cell lymphoma (DLBCL). 47 DLBCL patients underwent PET/CT before initiation and after 2–4 cycles of chemotherapy were included. The SUVmax of the dominant lesions were calculated. Ki67 positive indices were provided by enzyme-labeled immuno-histochemistry. SPSS17.0 was used for statistical analysis. ΔSUVmax of different groups were compared by t test. Receiver-operator characteristic analysis was performed to determine the optimal cutoff values. Kaplan-Meier analyses of PFS (Progression-free survival) were compared using log-rank test. The average of ΔSUVmax and ΔSUVmax% were 11.53 and 69.10%, respectively. The optimal cutoff values of ΔSUVmax and ΔSUVmax% were 11.45 and 82.92%, respectively. Higher ΔSUVmax and ΔSUVmax% indicated longer PFS (p<0.001). The optimal cutoff value of Ki67 was 55%. Ki67≥55% was revealed to be an indicator of shorter PFS (p=0.019). Either ΔSUVmax≤11.45 or Ki67>55% was defined as an indicator to poor outcome and scored 1 point. The PFS rate was 100% in patients scored 0 point, yet 0% in patients scored 2 points. PFS tended to be shorter along with the score getting higher (p=0.006). ΔSUVmax and Ki67 positive index were both of significance in DLBCL prognosis. The prognostic value may be confirmed when ΔSUVmax was accordant with Ki67.