Studies of Marrow Transplantation, Chemotherapy and Cross-circulation in Canine Lymphosarcoma

During a 4-year period 75 dogs with malignant neoplasms were referred by veterinarians to a medical research unit interested in the study of canine lymphoma and leukemia. Sixty dogs had lymphoblastic lymphosarcoma, six had leukemia, and nine had nonhemopoietic malignancies. Twenty-nine allogeneic marrow grafts were attempted following 1200 R of whole-body irradiation. Seven dogs with lymphosarcoma and one dog with anaplastic carcinoma survived beyond the first postirradiation week and demonstrated evidence of allogeneic marrow engraftment. All animals died, two following graft rejection, two with intercurrent sepsis and three of secondary disease. The two longest survivors, dying of secondary disease on days 46 and 60, were free of clinical or histologic evidence of tumor. Four dogs with lymphosarcoma were treated for 18 to 30 days with L-asparaginase. Rapid tumor regression was noted in all. Eleven dogs were treated with weekly intravenous cyclophosphamide. Moderate to marked node regression occurred in nine cases. Lymphocytes from normal dogs presensitized with tumor tissue were given by cross circulation to tumor-bearing hosts. Tumor regression occurred in two of five dogs. It was concluded that canine lymphosarcoma is a disease with uniform histologic and clinical features suitable for evaluation of therapeutic procedures in the treatment of a spontaneous malignancy in a randomly bred species.