Prolonged Disease-Free Survival in Dogs With Lymphoma After Total-Body Irradiation and Autologous Marrow Transplantation

Dogs with spontaneous lymphoma were treated with one of three aggressive treatment protocols: (1) combination chemotherapy with cyclophosphamide, L-asparaginase. Oncovin#{174}, and prednisone (CLOP); (2) combination chemotherapy with nitrogen mustard, Oncovin#{174}, prednisone, 1-asparaginase, and 6-mercaptopurine (MOPA-6); or (3) MOPA-6 followed by total-body irradiation (TBI) and autologous marrow transplantation. Of 14 dogs treated with CLOP, 9 achieved complete remission, but median disease-free survival was only 38 days. Of 57 evaluable dogs treated with MOPA-6, 34 (60%) achieved complete remission. Twelve dogs in complete remission received no additional therapy; median disease-free survival was 73.5 days, and the longest duration of complete remission was 113 days. Seventeen dogs in complete remission received 1100 R TBI followed by infusion of fresh marrow aspirated immediately prior to irradiation. Median disease-free survival was 206 days and was significantly prolonged compared to dogs receiving MOPA-6 alone (p 0.01). Furthermore, 4 dogs remain alive in unmaintained complete remission 1-2 yr after irradiation. Thus, canine lymphoma was responsive to combination chemotherapy. but remissions were short. Consolidation of chemotherapy induced complete remission with TBI and autologous marrow transplantation prolonged disease-free survival and resulted in long-term unmaintamed complete remission in a minority of dogs. This large animal model may help to define the role of TBI and autologous marrow grafting in the treatment of lymphoma.