ISHL12 Abstract 136

Interim PET-guided treatment of early-stage nodular lymphocyte-predominant Hodgkin lymphoma: a subgroup analysis of the GHSG HD16 and HD17 studies

Background: The optimal treatment for patients with early-stage nodular-lymphocyte predominant Hodgkin lymphoma (NLPHL) other than stage IA is undefined.

Patients and Methods: We investigated characteristics and outcomes of patients with early-stage NLPHL (favorable: 85 patients; unfavorable: 15 patients) who had treatment within the randomized GHSG HD16 and HD17 studies. Results were compared to those from patients with classical Hodgkin lymphoma (cHL) (favorable: 495 patients; unfavorable: 764 patients) treated within the same studies. Chemotherapy consisted of 2 cycles of ABVD (HD16) or 2 cycles of escalated BEACOPP plus 2 cycles of ABVD („2+2“) (HD17). In the experimental study arms, consolidation radiotherapy (RT) was applied on the basis of the result of interim positron emission tomography (PET-2). In the standard arms, consolidation RT was mandatory. Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method.

Results: In the HD16 and HD17 studies, 62/85 (73%) and 13/15 (87%) NLPHL patients were male as compared to 254/495 (51%) and 337/764 (44%) cHL patients. The median age of patients with NLPHL was 37 years in the HD16 study (cHL: 36 years) and 42 years in the HD17 study (cHL: 31 years). The majority of NLPHL patients included in the HD16 and HD17 studies presented with a typical histopathological growth pattern (HD16: 66%; HD17: 70%)
The 5-year PFS for all NLPHL patients was 90.3% (cHL: 90.8%) in the HD16 study and 92.9% (cHL: 95.7%) in the HD17 study. In the HD16 study, the 5-year PFS for the subgroup of PET-2-positive NLPHL patients was 89.3% (cHL: 91.6%); PET-2-negative NLPHL patients had a 5-year PFS of 91.0% (cHL: 90.4%). For PET-2-negative NLPHL patients assigned to the chemotherapy only arm, the 5-year PFS was 83.0% (cHL: 88.2%) whereas PET-2-negative NLPHL patients treated with chemotherapy plus RT had a 5-year PFS of 100% (cHL: 92.3%) (p=0.05). Subgroup analyses according to the PET-2 result were not conducted for NLPHL patients treated within the HD17 study due to the small number of individuals with NLPHL histology included in this trial.
The 5-year OS for NLPHL patients treated within the HD16 and HD17 studies was 100% (cHL: 98.6% in HD16; 99.2% in HD17).

Conclusion: Contemporary HL-directed treatment results in excellent 5-year outcomes for patients with newly diagnosed early-stage NLPHL and should thus be considered as valid approach for this patient group.