CHEMOTHERAPYRandomized control studies initiated by the Polycythemia Vera Study Group (PVSG) (1) and the European Organization for Research and the Treatment of Cancer (EORTC) (2) for the treatment of polycythemia Vera (PV) have provided important insights as to the pathophysiology and the complications associated with treatment of this preneoplastic state. The PVSG study consisted of a three-arm randomization. The first arm was phlebotomy alone; the second, 32P plus phlebotomy; and the third, chlorambucil plus phlebotomy. A total of 43 1 previously untreated patients were randomized into one of these arms. The study quickly demonstrated that there was a significant increase in recurrent thrombotic complications and deaths in the phlebotomy arm which was discontinued. A surprising finding was an increased risk of leukemia in the chlorambucil arm. By 1980, the risk of acute leukemia was 2.3 times that of patients treated with 32P, and 13 times the incidence in the phlebotomy arm. The increased risk was statistically significant at the p < 0.002 level. The higher the dose and the longer the duration of chlorambucil therapy, the greater was the incidence of leukemia. Copyright 0 1986 by Marcel Dekker, Inc. 2. Haanen C, Math& G: Treatment of polycythaemia Vera by radiophosphorus or busulfan: A randomized trial. Br J Cancer 3. Tartaglia AP, Goldberg JD, Silverstein MN et al: Aspirin and Persantine do not prevent thrombotic complications in patients with polycythemia Vera treated with phlebotomy. Blood 58:24Oa(l), 1981. 4. Brodsky I: The use of ferrokinetics in the evaluation of busulphan therapy in polycythaemia Vera. Br J Haematol 10:291-298, 1%. 5. Bmdsky I Busulphan treatment of polycythemia Vera. Br J Haemat01 6. Dunn CDR: The chemical and biological properties of busulphan ('Myleran'). Expt Hematol 2:lOl-117, 1974. 44~75-80, 1981. 52:1-6, 1982. Cancer Invest Downloaded from informahealthcare.com by Mcgill University on 12/13/14For personal use only.
