AbstractCombined total body irradiation (TBI) and Prednimustine were prospectively evaluated in 30 patients affected either with chronic lymphocytic leukemia (CLL) or with low-grade non-Hodgkin's lymphoma (NHL) eleven patients were previously treated. Between January 1984 and May 1987, 20 evaluable patients with CLL, median age 66 years (range 43–82), classified according to Rai (4 in stage I, 10 in stage II, 4 in stage III, 2 in stage IV) and 10 evaluable patients with NHL low-grade malignancy according to the Working Formulation, Stages III and IV, median age 54 years (range 32–71) were treated using a 6 MeV Linear Accelerator, applying two opposite alternating fields including total body, with a fraction of 15 cGy, 2 fractions weekly (3-day interval) for a total dose of 150 cGy given over 5 weeks. Prednimustine (100 mg/m2, orally, for 5 consecutive days, every 3–4 weeks, for 6–9 courses) was administered 2 months after TBI treatment, as consolidation therapy. By May 1989, a total of 85% hematological responses (defined as normalization of the differential white cell count, of the total blood cell count and of bone marrow infiltration) were obtained after combined treatment in CLL patients; moreover 3 CR (according to the WHO criteria), 75% with splenomegaly reduction and 40% with lymphadenopathy reduction were seen. Ninety percent objective responses (5 CR and 4 PR) were observed in the NHL patients, with 50% having splenomegaly reduction and 67% lymphadenopathy reduction. The median response time in the two groups was, respectively, 14 and 23 months. The overall toxicity (WHO grades 1,2,3,4) after combined treatment was 65% and 70% in the two patient groups. WHO grade III toxicity, completely reversible, was verified in only 16.6% of the cases; all cases, except one, were previously treated. Additionally, 1 toxic death (grade IV thrombocytopenia and leukopenia) was observed in a heavily pretreated patient affected with CLL after TBI alone. Prednimustine regimen was generally well tolerated. The high response rate and acceptable toxicity, confirms the feasibility and the usefulness of TBI in the context of a combined treatment for CLL and low-grade NHL patients. However in order to further reduce the severe toxic side effects, observed in one patient, white blood cells and platelet count should be plotted and monitored carefully, particularly in pretreated patients.