Prognostic Value of Interim ¹⁸F-FDG PET in Patients with Diffuse Large B-Cell Lymphoma: SUV-Based Assessment at 4 Cycles of Chemotherapy

Abstract

Interim 18 F-FDG PET (after 1-4 cycles of chemotherapy) may be useful for tailoring a risk-adapted therapeutic strategy in lymphoma. The purpose of this study was to investigate whether semiquantification of standardized uptake values (SUVs) may help to improve the prognostic value of 18 F-FDG PET, compared with visual analysis, after 4 cycles of chemotherapy. Methods: In a previous report, we showed that a 65.7% reduction in maximal SUV (SUVmax) between baseline (PET0) and 2 cycles of chemotherapy (PET2) better predicted event-free survival in 92 prospective patients with diffuse large B-cell lymphoma, by reducing false-positive interpretation of visual analysis. Eighty patients also underwent 18 F-FDG PET after induction had been completed, at 4 cycles of chemotherapy (PET4). Images were interpreted visually (as negative or positive) and by computing the optimal percentage of SUVmax reduction between PET0 and PET4. Survival curves were estimated using Kaplan-Meier analysis and compared using the log-rank test. Median follow-up was 41 mo. Results: With visual analysis, the 2-y estimate for event-free survival was 82% in the PET4-negative group, compared with 25% in the PET4-positive group (P , 0.0001, accuracy of predicting event-free survival, 81.3%). An optimal cutoff of 72.9% SUVmax reduction from PET0 to PET4 yielded a 2-y estimate for event-free survival of 79% in patients with reduction of more than 72.9%, versus 32% in those with reduction of 72.9% or less (P , 0.0001; accuracy of predicting event-free survival, 77.5%). Conclusion: Although SUV semiquantification helps reduce false-positive interim 18 F-FDG PET interpretations at 2 cycles, its performance is equivalent to visual analysis at 4 cycles, when most of the therapeutic effect has occurred upstream. This approach may be useful for objectively tailoring consolidation strategies.

Midtreatment 18F‐fluorodeoxyglucose positron‐emission tomography in aggressive non‐Hodgkin lymphoma

“…[5][6][7][8][9][10][11] The superiority of PET over computed tomography in identifying active disease after therapy completion has recently led to the revision of response criteria. 32 Several studies have shown that after 1-3 cycles of chemotherapy for aggressive NHL, 3,[5][6][7][8][9][10][11]34 early metabolic changes as documented by early or interim PET scan may be highly predictive of final treatment response and progression-free survival. However, the real benefit of interim PET in aggressive NHL has been questioned recently.…”

“…9,11,38 All of these variables, which are often taken into consideration in the same report, can modify and alter the results significantly; consequently, data obtained from interim PET evaluations performed at different observation periods should not be pooled. Furthermore, the potential different response related to the inclusion or exclusion of rituximab in the treatment regimen must be considered.…”

“…[1][2][3][4] In particular, several studies that have evaluated the role of PET as a prognostic tool during chemotherapy have reported its ability to predict outcomes in aggressive NHL. [5][6][7][8][9][10][11] In force of the pivotal role played by PET in staging, restaging, and response evaluation, the International Workshop Criteria for malignant lymphoma 12 have been revised to incorporate the PET data in NHL outcome assessment, but only at the end of therapy.…”

“…Recent reports of PET evaluation have demonstrated a greater degree of accuracy in early response assessment compared with computed tomography. [5][6][7][8][9][10][11] However, the benefit of midtreatment (or interim) PET evaluation in aggressive NHL is still a matter of debate, 24 and a meta-analysis conducted by Terasawa et al 3 indicated that interim PET has unproven reliability in routine clinical practice.…”

Prognostic Value of Metabolic Activity Measured by 18F-FDG PET/CT in Patients with Advanced Endometrial Cancer

“…Tumor glucose metabolism measured by FDG PET has been reported to be valuable in predicting the outcome of many cancers, such as head and neck squamous cell carcinoma [6][7][8], lymphoma [9][10][11], and esophageal [12] and lung cancers [13]. However, studies on the prognostic value of FDG PET in endometrial cancer are limited.…”