TREATMENT OF POLYCYTHEMIA - I - RANDOMIZED PROTOCOL IN POLYCYTHEMIA-VERA PATIENTS COMPARING P-32 ALONE AND P-32 FOLLOWED BY LOW-DOSE HYDROXYUREA MAINTENANCE THERAPY

Aims. - To compare by a prospective study in high risk polycythemia ve ra (PV) patients P-32 alone and P-32 followed by low-dose hydroxyurea (HU) maintenance therapy. Toxicity, efficiency, and leukemogenic poten tial were studied. Patients. - 483 patients with a documented PV, aged more than 65 years at diagnosis, were included between 1980 and 1996 in a prospective study comparing P-32 alone and P-32 followed by low-d ose HU maintenance therapy. Blood cell counts were performed every two months and a clinical evaluation by a specialist was obtained every f our or six months. Results. - Treatments mere well tolerated, but chro nic leg ulcers were observed in the maintenance therapy arm. The risk of leukemia was about 15 % at the 15 th year in the group of patients treated by np alone, but reached 30 % in the group receiving maintenan ce therapy. In both arms, there was no significant correlation between occurrence of leukemia and the total dose of (32)p. There was a corre lation between the leukemic risk and disease severity, estimated on th e frequency of relapse. Cancer occurrence was slightly higher than exp ected in the maintenance arm. HU treatment did not protect against pro gression to myelofibrosis, probably due to the lack of maintenance of an efficient myeloid or megakaryocytic suppression. Median life-span w as slightly shorter in the group receiving HU maintenance. In all case s, life-span was only one year lower than that observed in the referen ce population. Conclusion. - For all these reasons, we suggest the use of P-32 alone in elderly patients; complementary chemotherapy should only be prescribed in the cases with short-term relapse, and late resi stance to P-3Z.