ABCL-007 Semiquantitative Measurements of Standard-Uptake-Value (ΔSUV) in Assessment of Patients Response and Outcomes in Aggressive Lymphomas

Abstract

Positron emission tomography (PET) with 18-fluoro-2-deoxy-D-glucose ([18 F] FDG) is an essential tool for accurate staging, early, and late therapy response assessment in all FDG-avid lymphomas. To evaluate the accuracy of ΔSUV max in assessment of response to treatment in patients with lymphoma. This study was conducted between October 2019 and October 2021. Seventy-three patients diagnosed as high-grade lymphoma or Hodgkin disease (HD) were enrolled in the study. PET/CT examinations were performed at baseline (PET0), after the second, the fourth cycle of chemotherapy and at the end of treatment. PET-CT scans were analyzed according to the Deauville 5-point scale (5-PS). According to SUV-based assessment, PET/CT was considered negative when ΔSUV max at 2nd cycle (PET0-2) is more than 66% and ΔSUV max at 4th cycle (PET0-4) is more than 70%, respectively. The change in activity (ΔSUV) from initial (SUVmax1) to later scans (SUVmax2) was calculated as: SUV (%) = 100 x ([SUVmax2/SUVmax1] -1). Biopsy was taken if PET 2 or 4 is visually positive with negative delta SUV max, or in case of new lesions if other sites have improved. SUV uptake values at baseline were 16.30 ± 9.36 in NHL versus 12.55 ± 6.78 in HL. After 2 cycles of chemotherapy, (78.1%) had negative PET based on ΔSUV max raised to (86.3%) by the end of 4th cycle and this was different from 5PS where only (60.5%) raised to (74.4%) after the 4th cycle. In comparison with results of biopsy, ΔSUV0-2 has sensitivity 80%, specificity 94.1%, accuracy 90.91 % with P value (0.001) also, ΔSUV0-4 has sensitivity 80%, specificity 100%, accuracy 95.45 % with high agreement with P value (<0.001). On the contrary, the visual 5-PS analysis 0-2 specificity 17.65%, accuracy 36.36 with P value (<0.321). Also, the visual 5-PS analysis 0-4 specificity 41.18 %, accuracy 54.55% with P value (<0.082). After 4 cycles 22 patients needed to undergo biopsy because inconclusive results of PET. Comparison reveled that using ΔSUV max demonstrated higher specificity. ΔSUV max is comparable to biopsy and significantly more accurate than Deauville criteria in assessment of response to treatment.