Treatment of canine malignancies by 1200 R total body irradiation and autologous marrow grafts.

ABSTRACT

Twenty-five dogs with malignant lymphoma (L) and 18 dogs with solid, nonhematologic tumors (ST) were treated with 1200 R total body irradiation (TBI). Rescue from the otherwise lethal hemopoietic toxicity by infusion of autologous marrow aspirated before TBI was attempted, and survival, response to TBI, and immune reactivity post-grafting were determined. Eight L dogs survived more than 14 days post TBI and marrow grafting, and 12 out of 19 evaluable dogs showed a decrease of 75 per cent or more in clinically detectable tumor. There was no evident relationship between clinical status or marrow status before TBI and survival of more than 14 days or tumor response to TBI. Seven of the 8 survivors ultimately developed recurrent tumor. Eight ST dogs survived more than 14 days. Only 4 of 14 evaluable ST dogs showed significant clinical response of their tumor to TBI. Humoral and cellular immune reactivity were significantly impaired during the 10-week period following TBI and marrow grafting in all dogs studied. These results indicate that therapy in addition to lethal doses of TBI is necessary to cure spontaneous L or to significantly affect ST in dogs. They also provide baseline data which are necessary to assess the immunotherapeutic effectiveness of allogeneic marrow grafts.