Treatment of Primary Lymphoma of Bone in Patients Under 18 with Incomplete Resection, Elevated LDH, and CNS-Negative Stage III or Stage IV Disease

This protocol addresses mature aggressive B-cell lymphoma/leukemia presenting as primary lymphoma of bone in pediatric patients. The specific population is defined by incomplete resection, confirmed CNS-negative status, and one of the following: stage III disease with serum LDH at least twice the upper limit of normal, stage IV disease, or Burkitt leukemia.

Risk groupings in this setting distinguish between incomplete stage III disease with LDH elevations above or at least four times the upper limit of normal, and stage IV or Burkitt leukemia (B-AL) presentations with or without marked LDH elevation — all confirmed CNS-negative. The patient's age under 18 at diagnosis is a defining eligibility criterion.

Management involves intensive sequential multi-cycle chemotherapy. Two established conceptual frameworks apply here: a BFM-based approach using a structured sequence of distinct alternating cycle types, and an EICNHL-based approach in which an anti-CD20 monoclonal antibody is incorporated alongside the chemotherapy backbone. The specific cycle sequence, response-adapted modifications, and full agent selection are outlined in the complete protocol.

• Absence of blasts in the bone marrow prior to the third course of treatment.
• Absence of blasts in the cerebrospinal fluid during the third course of treatment.