Nodular lymphocyte-predominant Hodgkin lymphoma: a unique disease deserving unique management.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma entity with an incidence of 0.1 to 0.2/100 000/y. Compared with the more common subtypes of classical Hodgkin lymphoma, NLPHL is characterized by distinct pathological and clinical features. Histologically, the disease-defining lymphocyte predominant cells consistently express CD20 but lack CD30. Clinically, NLPHL mostly has a rather indolent course, and patients usually are diagnosed in early stages. The prognosis of early-stage NLPHL is excellent, with progression-free survival and overall survival rates exceeding 90% after involved-field radiotherapy (IF-RT) alone (stage IA) or combined modality treatment consisting of a brief chemotherapy with 2 cycles of ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) chemotherapy followed by IF-RT (early stages other than stage IA). In contrast, patients with advanced disease at diagnosis tend to relapse either with NLPHL histology or with histological transformation into aggressive B-cell non-Hodgkin lymphoma despite more aggressive first-line treatment with 6 to 8 cycles of multiagent chemotherapy. However, even NLPHL patients with multiple relapses successfully respond to salvage therapy in many cases. Salvage therapies range from single-agent anti-CD20 antibody treatment to high-dose chemotherapy followed by autologous stem cell transplantation. Treatment at disease recurrence should be chosen on the basis of various factors, including histology at relapse, time to relapse, extent of disease at relapse, and prior treatment. Because death among NLPHL patients is more often caused by therapy-related late effects than lymphoma-related complications, optimizing the risk-benefit ratio of treatment by decreasing toxicity whenever possible is the major goal of clinical research in this disease.