Comparison of interim PET response to second-line vs. to first-line treatment in classical Hodgkin lymphoma - contribution to the development of response criteria for relapsed or progressive disease.

Regine, Kluge; Wittig, Tim; Georgi, Thomas Walter; Kurch, Lars; Sabri, Osama; Wallace, W Hamish; Klekawka, Tomasz; Fernández-Teijeiro, Ana; Ceppi, Francesco; Karlén, Jonas; Pears, Jane; Cepelová, Michaela; Fosså, Alexander; Beishuizen, Auke; Hjalgrim, Lisa Lyngsie; Körholz, Dieter; Mauz-Körholz, Christine; Hasenclever, Dirk

Rationale: In first-line treatment of Hodgkin lymphoma (HL) Deauville scores 1-3 define complete metabolic remission. Interim 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 treatment response to first-line and to second-line treatment in 127 patients with classical Hodgkin lymphoma who experienced relapse. 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. Empirical cumulative distribution functions (ECDF) of the qPET values were used to systematically analyze the response to first-line and second-line treatment. Results and Conclusion: Individual patients responded variably to first-line and second line treatment. However, the ECDF of the qPET values from all patients were nearly superimposable. This supports that first-line and second-line treatment in HL do not require different response criteria.