Outcome and pathologic classification of children and adolescents with mediastinal large B-cell lymphoma treated with FAB/LMB96 mature B-NHL therapy

Mediastinal large B-cell lymphoma (MLBL) represents 2% of mature B-cell non-Hodgkin lymphoma in patients ≤ 18 years of age. We analyzed data from childhood and adolescent patients with stage III MLBL (n = 42) and non-MLBL DLBCL (n = 69) treated with Group B therapy in the French-American-British/ Lymphome Malins de Burkitt (FAB/LMB) 96 study. MLBL patients had a male/female 26/16; median age, 15.7 years (range, 12.5-19.7); and LDH < 2 versus ≥ 2 x the upper limit of normal, 23:19. Six MLBL patients (14%) had < a 20% response to initial COP (cyclophosphamide, vincristine, and prednisone) therapy. Central pathology revealed approximately 50% with classical features of primary MLBL. Five-year event-free survival for the stage III MLBL and non-MLBL DLBCL groups was 66% (95% confidence interval [CI], 49%-78%) and 85% (95% CI, 71%-92%), respectively (P < .001; 14%). The 5-year overall survival in the 42 MLBL patients was 73% (95% CI, 56%-84%).We conclude that MLBL in adolescent patients is associated with significantly inferior event-free survival compared with stage III non-MLBL DLBCL and can be of multiple histologies. Alternate treatment strategies should be investigated in the future taking into account both adult MLBL approaches and more recent biologic findings in adult MLBL.