The objective of this study is to investigate the prognostic value of the percentage change of maximum standardized uptake value (ΔSUVmax) assessed by PET/CT scan after 2 cycles of chemotherapy (iPET2) in patients with classic Hodgkin's lymphoma (CHL). ΔSUVmax was calculated as follows: the ratio of (SUVmax at baseline-SUVmax at iPET2)/SUVmax at baseline which was determined before initiation of ABVD chemotherapy. The median ΔSUVmax of 46 patients at iPET2 was 87.9% (range - 6.1-100.0%). The optimal ΔSUVmax cutoff value for progression-free survival (PFS) was 83.0% with the receiver operating characteristic curve. The area under the curve for PFS was 0.886 (95% CI 0.788-0.984, p < 0.001). The median PFS of 29 (63.0%) patients who achieved a SUVmax reduction of more than 83.0% was 34 months. The median PFS of 17 (37.0%) patients with ΔSUVmax < 83.0% was 9 months. This difference was significant (p < 0.001). Cohen's kappa coefficient of Deauville Score (DS)- and ΔSUVmax-judged positivity was 0.752 (95% CI 0.592-0.992, p < 0.001), suggesting a strong consistency. Multivariate analysis showed that ΔSUVmax at iPET2 less than 83.0% of SUVmax at diagnosis was an independent factor predicting PFS [HR = 11.339, 95% CI 2.485-51.742, p = 0.002]. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ΔSUVmax<83.0% was 84.6%, 81.8%, 67.7%, 93.1%, and 82.6%, which was similar to that of DS as 61.5%, 87.9%, 66.7%, 85.3%, and 80.4%, respectively. ΔSUVmax<83.0% of iPET2 effectively predicts prognosis of patients with CHL treated with ABVD.
Keywords: Classic Hodgkin’s lymphoma; Percentage change of maximum standardized uptake value; Positron emission tomography.