Relapsed Nodular Lymphocyte-Predominant Hodgkin Lymphoma: An Analysis from the German Hodgkin Study Group (GHSG)
Authors: Eichenauer Dennis A. , Pluetschow Annette , Schroeder Lena , Fuchs Michael , von Tresckow Bastian , Diehl Volker , Borchmann Peter , Engert Andreas 
Published: October 2019

Abstract
Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare entity accounting for approximately 5% of all Hodgkin lymphoma (HL) cases. Pathological and clinical features differ from classical HL (cHL). Pathologically, the malignant lymphocyte predominant (LP) cells stain consistently positive for CD20 and are negative for CD30. Clinically, NLPHL often has an indolent course. However, patients tend to develop late and multiple relapses. Since data on the treatment of relapsed NLPHL are scarce, we used the database of the German Hodgkin Study Group (GHSG) to obtain information on characteristics, treatment and outcome of NLPHL patients with disease recurrence after initial response to first-line treatment. A total of 99 patients who had their first-line treatment within 12 GHSG studies between 1993 and 2008 and subsequently relapsed with NLPHL histology were identified and considered for the present analysis. Patients with primary disease progression or transformation into aggressive B-cell non-Hodgkin lymphoma (NHL) at relapse were not included. At initial NLPHL diagnosis, the median age of the 99 eligible patients was 40 years; 66% of patients had early favorable, 14% had early unfavorable and 20% had advanced stages. First-line treatment consisted of radiotherapy (RT) alone in 22%, combined-modality treatment (CMT) in 68%, single agent anti-CD20 antibody treatment with rituximab in 7% and chemotherapy alone in 3% of patients. At a median observation of 10.8 years from initial diagnosis, relapse occurred after a median of 6.2 years. At relapse, 32% of patients received RT alone or conventional chemotherapy followed by RT, 28% received high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) and 26% had anti-CD20 antibody treatment either alone or in combination with conventional chemotherapy. In 13% of cases, patients either received no salvage treatment or the kind of salvage treatment was unknown. At a median observation of 3.8 years after disease recurrence, 11% of patients had developed a second relapse and 4% a third relapse. Five-year progression-free survival (PFS) estimates after occurrence of the first relapse were 78.6% (95%-CI: 61.6%-95.6%), 90.0% (95%-CI: 76.5%-100%) and 72.4% (95%-CI: 53.6%-91.2%) after salvage treatment with RT alone or conventional chemotherapy followed by RT, high-dose chemotherapy followed by ASCT and anti-CD20 antibody treatment optionally combined with conventional chemotherapy, respectively. Thus, there were no significant differences between the applied approaches. Only 10 patients (10%) died during observation; 5 deaths were NLPHL-related, 3 patients died due to second malignancies, and 1 patient each died from respiratory failure and infection. Hence, 90% of NLPHL patients who developed disease recurrence after initial response to first-line treatment were alive at the end of follow-up. Given these excellent survival data, it appears necessary to define patients who are sufficiently treated with non-toxic approaches associated with a potentially low risk for the development of late effects. A pragmatic approach based on the present data may consist in the division of relapsed NLPHL patients into 2 groups. Patients with a longer remission after first-line treatment who present with limited tumor mass at relapse may be treated with anti-CD20 antibodies alone or in combination with conventional chemotherapy, RT alone or conventional chemotherapy followed by RT. In contrast, patients with early disease recurrence and more extensive disease at relapse including extranodal involvement may require more aggressive treatment consisting of high-dose chemotherapy followed by ASCT.

Disclosures
von Tresckow: Novartis: Consultancy, Other: travel grants, Research Funding; Takeda: Consultancy, Other: travel grants; Millenium: Consultancy. Engert:Takeda: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding.