Burkitt's lymphoma: a clinical study of 110 patients.

One hundred and ten previously untreated patients with Burkitt's lymphoma were studied prospectively over a period ranging from over 1 year to 5 years. Of 103 patients who were treated with cyclophosphamide as a single agent, 79 (77%) achieved complete remission. Vincristine plus methotrexate or cytosine arabinoside induced complete remissions in only two of 24 patients who failed to respond to cyclophosphamide. Fifty-two percent of patients who entered complete remission subsequently relapsed with tumor. Relapse was significantly higher in patients who presented with disseminated disease (Stage III-IV) than in patients with localized disease (Stage I-II). Patients who relapsed early (remission duration less than 12 weeks) had a significantly worse prognosis than patients who relapsed late (remission duration greater than 12 weeks). Actuarial calculated 2- and 4-year survival for all patients was 44% and 38%, respectively. Factors that adversely affected survival were primary resistance to cyclophosphamide, early tumor relapse, central nervous system disease, and involvement of abdominal organs.