The prognostic significance of ΔSUVmax assessed by PET/CT scan after 2 cycles of chemotherapy in patients with classic Hodgkin's lymphoma.

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.