THE ROLE OF RADIATION-THERAPY IN THE TREATMENT OF ACUTE LYMPHOBLASTIC-LEUKEMIA WITH LYMPHOMATOUS PRESENTATION - A REPORT FROM THE CHILDRENS CANCER GROUP

Purpose: Childrens Cancer Group 123 was a trial of intensive multidrug chemotherapy as well as cranial irradiation and bulk disease irradiation in children with acute lymphoblastic leukemia with lymphomatous presentation (bulk disease and either T-cell phenotype, high white blood count, or absence of anemia), a poor prognostic group with an increased risk of central nervous system (CNS) and other extramedullary recurrence. Methods and Materials: Three hundred eight patients without CNS disease were randomized among three regimens: A-BFM chemotherapy (designed for high risk ALL patients) with 1800 cGy cranial irradiation; B-LSA2L2 chemotherapy (designed for non-Hodgkins lymphoma patients) with 1800 cGy cranial irradiation and 1500 cGy to nonabdominal bulk disease; C-Reg B without cranial irradiation. All patients received intrathecal methotrexate throughout therapy. Radiation treatment records were reviewed. Results: With a minimum 52-month follow-up, Regimen B and C patients had 5-year actuarial CNS relapses of 7% and 17% (p = 0.01) and event-free survivals of 53% and 39% (p = 0.04). Patients with white blood count < 50,000/mm3 did not benefit from cranial irradiation. Regimen A patients had the same CNS relapse rate as Regimen B patients but an improved event-free survival. Regimen B and C patients with large mediastinal masses who received their assigned chest radiation had a lower event rate than those who did not (p = 0.06). Patients whose cranial fields did or did not encompass the entire meningeal surface had equivalent CNS relapse rates. Conclusion: Patients treated with LSA2L2 chemotherapy, a less than optimal regimen, benefited from cranial and mediastinal irradiation. Compliance with radiation volume guidelines was not essential for patients to receive the benefit of cranial irradiation.