Positron Emission Tomography Status and Tandem High-Dose Therapy Favorably Influence Outcome of Patients with Relapsed and/or Refractory Hodgkin Lymphoma

Abstract 335

The cure of relapsed or refractory Hodgkin Lymphoma (HL) still remains a challenge. High dose chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard of care but almost half of patients relapse after ASCT and have poor outcome. Predictive factors including an interval from end of first line therapy to relapse shorter than 12 months, an Ann-Arbor stage III or IV at relapse, and relapse in previously irradiated field are currently used to identify patients with poor outcome. Development of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) assessment improves evaluation of response both in first line and salvage treatments. The aim of our study is first to confirm the predictive value of PET status before ASCT and then to compare ASCT strategy (single versus tandem) in patients with relapsed and/or refractory HL. We here report a series of 111 consecutive patients with relapsed and/or refractory HL who achieved at least partial remission (PR) at PET evaluation after one line of salvage chemotherapy and who underwent single or tandem ASCT. PET response assessment showed 85 (77%) patients in CR (PET- group) and 26 (23%) in PR (PET+ group). Five-year overall (OS) and progression free survival (PFS) were 81% and 64% respectively. There were significant differences in 5-year PFS (79% versus 23%, p<0.001) and 5-year OS (90% versus 55%, p=0.001) between PET- and PET+ groups respectively. This predictive value remained significant in both favorable/intermediate and unfavorable subgroups. In PET+ subgroup analysis, tandem ASCT dramatically improved 5-years PFS, from 0% to 43% (p=0.034) compared to single ASCT. Multivariate analysis showed that PET status (HR: 5.26 [2.57–10.73]) and tandem ASCT (HR: 0.39 [0.19–0.78]) but not relapse risk (HR: 1.77 [0.80–3.92]) significantly influenced PFS, while only PET status significantly influenced OS (HR: 4.03 [1.38–11.75]). Our results suggest that I) PET status before ASCT must be considered as a strong and significant prognostic factor influencing outcome and identifying high risk patients for more intensive strategy II) Tandem ASCT improved outcome compared to single ASCT, especially for PET+ patients.