Radiophosphorus (32P) treatment of bone marrow disorders in dogs: 11 cases (1970-1987).

Between March 1970 and February 1987, radiophosphorus (32P) was used to treat bone marrow disorders in 6 dogs; 4 had polycythemia vera and 2 had essential thrombocythemia. Activities of 32P given initially ranged from 2.4 to 3.3 mCi/m2. Four dogs responded well to 32P treatment, with gradual resolution of high RBC or platelet counts. Two of these dogs died of intercurrent disease unrelated to their bone marrow disorder, before blood counts could be stabilized. Two dogs did not respond to the initial 32P treatment nor to additional treatments with 32P, and had clinical signs and blood counts stabilized by use of phlebotomy or chemotherapeutic agents. We reviewed and analyzed 5 other cases of bone marrow disorders in dogs treated with 32P and included the findings from their records with the records of our 6 dogs in this retrospective analysis. Of the 8 dogs with polycythemia vera treated with 32P, 5 were given a single treatment that controlled clinical signs and blood counts for the remainder of the follow-up period. Of the 3 dogs treated for thrombocytosis with 32P, 2 had blood counts that responded to a single treatment.