Treatment of pediatric lymphocyte predominant Hodgkin lymphoma (LPHL): A report from the Children's Oncology Group.

Abstract

10000 Background: LPHL, an uncommon subtype of HL, typically presents with low stage disease and responds to regimens used for classical HL. Recurrence is uncommon, but second malignant neoplasms (SMN) or development of non-Hodgkin lymphoma (NHL) can occur. Therefore, reducing radiation exposure may be of benefit. We report the results of a prospective trial in which a selected subset of patients had surgery alone and the remainder were treated with limited chemotherapy +/- involved-field radiation therapy (IFRT). Methods: Patients ages 0-21 years with newly diagnosed, low risk LPHL were eligible for AHOD03P1. Low risk was defined as clinical Stage IA or IIA without bulk disease (mediastinal mass > 1/3 of the thoracic diameter or nodal aggregate > 6 cm). Patients with Stage IA LPHL with an unresected node or more than a single involved node or Stage IIA were treated with 3 cycles of AV-PC (doxorubicin/vincristine/prednisone/cyclophosphamide). Patients with Stage IA LPHL in a single node that was completely resected were initially observed without further therapy; those who recurred after surgery with low risk LPHL received AV-PC x 3. Patients with < complete response (CR) to AV-PC x 3 received 2100 cGY IFRT. Results: 180 eligible patients with low risk LPHL were enrolled and completed study therapy. 52 patients underwent initial surgery alone; their 3 year EFS = 81.5%. 137 patients received AV-PC x 3; 128 were treated at diagnosis and 9 upon relapsing after surgery alone. 11 patients receiving AV-PC had < CR and received IFRT. 12 first events occurred among these 137 patients (11 relapses and 1 SMN, a NHL). One relapse occurred in a patient who received IFRT. The median follow-up among the 125 remaining patients is 39 (range 3 -76) months. Current 4-year EFS estimate is 88.1% (95% CI: 79.5%-93.3%) for these 137 patients. 4 year EFS for the entire cohort of 180 patients = 86.2%; their overall survival (OS) is 100%. Conclusions: Pediatric LPHL patients have an excellent EFS with chemotherapy that is less intensive than standard regimens; >90% of patients can avoid RT. NHL as a first event may be related to the underlying LPHL and not an effect of treatment. The salvage rate for the few relapses is high, and OS to date is excellent. Clinical trial information: NCT00107198.