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In first-line treatment of Hodgkin lymphoma (HL), Deauville scores 1-3 define complete metabolic remission. Interim 18F-FDG PET is also used for relapse-treatment adaptation; however, PET response criteria are not validated for relapse treatment. Methods: We performed a pairwise comparative analysis of early response to first- and second-line treatments in 127 patients with classic HL who experienced relapse. The patients participated in the prospective, multicenter EuroNet-PHL-C1 study. Residual uptake was measured retrospectively using the qPET method, a validated semiautomatic quantitative extension of the Deauville score. Empiric cumulative distribution functions of the qPET values were used to systematically analyze the response to first- and second-line treatments. Results: Individual patients responded variably to first- and second-line treatments. However, the empiric cumulative distribution functions of the qPET values from all patients were nearly superimposable. Conclusion: The findings support that first- and second-line treatments in HL do not require different response criteria.

The purpose of this study was to assess the predictive and prognostic value of interim FDG PET (iPET) in evaluating early response to immunochemotherapy after 2 cycles (PET-2) in diffuse large B-cell lymphoma (DLBCL) by applying 2 different methods of interpretation: the Deauville visual 5-point scale (5-PS) and a change in SUV (ΔSUV) by semiquantitative evaluation. Methods: In total, 145 patients with newly diagnosed DLBCL underwent pretreatment PET and PET-2 assessment. PET-2 was classified according to both 5-PS and percentage ΔSUV. Receiver-operating-characteristic analysis was performed to compare the accuracy of the 2 methods for predicting progression-free survival. Survival estimates, based on each method separately and combined, were calculated for iPET-positive (iPET+) and iPET-negative (iPET-) groups and compared. Results: Both with 5-PS and with ΔSUV-based evaluations, significant differences were found between the progression-free survival of iPET- and iPET+ patient groups (P < 0.001). Visually, the best negative predictive value (NPV) and positive predictive value (PPV) occurred when iPET was defined as positive if the Deauville score was 4-5 (89% and 59%, respectively). Using the 66% ΔSUV cutoff reported previously, NPV and PPV were 80% and 76%, respectively. ΔSUV at the 48.9% cutoff, reported for the first time here, produced 100% specificity along with the highest sensitivity (24%). The 5-PS and a semiquantitative ΔSUV of less than 48.9% for each PET-2 gave the same PET-2 classification (positive or negative) in 70% (102/145) of all patients. This combined classification delivered NPV and PPV of 89% and 100%, respectively, and all iPET+ patients failed to achieve or remain in remission. Conclusion: In this large consistently treated and assessed series of DLBCL patients, iPET had good prognostic value interpreted either visually or semiquantitatively. We determined that the most effective ΔSUV cutoff was 48.9% and that when combined with 5-PS assessment, a positive PET-2 result was highly predictive of treatment failure.cases, and MRI in 92.5% of cases; no false negative cases were observed. These results suggest the use of PET/CT as a unique diagnostic imaging tool after CCRT, to correctly assess residual and progression disease.

TO THE EDITOR: We would like to draw attention to accumulating evidence on the additional role of end-of-treatment PET/CT in advanced Hodgkin lymphoma (HL) ([1][1],[2][2]). Stephens et al. reported the results of long-term follow-up of HL patients included in the Southwest Oncology Group S0816

TO THE EDITOR: We read with interest Rekowski and colleagues’ article ([1][1]), which reported improved response discrim-ination using ΔSUVmax compared with the Deauville scale (DS) for interim PET (iPET) in diffuse large B-cell lymphoma but assessed only complete metabolic response versus no

REPLY: Mesguich et al. ([1][1]) commented on our publication, which reported the long-term outcome of patients with advanced-stage Hodgkin lymphoma undergoing interim 18F-FDG PET (after 2 cycles of chemotherapy; PET2) and PET2 response-adapted change in therapy in the SWOG S0816 trial ([2][2],[3][3

P. Shreve and D.W. Townsend, eds. New York, NY: Springer, 2011, 437 pages, $189 Hybrid imaging and diagnosis by multimodality imaging are broad and pervasive topics in the medical imaging field. The practice of integrating the interpretation of complementary imaging modalities for clinical