Haemopoietic stem cell transplantation for advanced polycythaemia vera or essential thrombocythaemia

Ten patients with polycythaemia vera (PV) and nine with essential thrombocythaemia (ET) received a haemopoietic stem cell transplant (HSCT) at the Fred Hutchinson Cancer Research Center between May 1988 and March 2000. HSCT was performed because of progression to the spent phase of the disease with myelofibrosis and splenomegaly in 10 patients and evolution into a myelodysplastic syndrome (MDS) or acute myelogenous leukaemia (AML) in nine patients. Patients were 18-59 years old (median 43). The interval from diagnosis to HSCT was 77-300 months (median 170). Seven patients were splenectomized before transplantation, and all but five had been treated with cytotoxic agents. Eleven patients received a transplant from a related, and eight from an unrelated, donor following conditioning with chemotherapy only or chemotherapy plus total body irradiation regimens. All evaluable patients achieved sustained engraftment. Twelve patients are surviving 5-116 months (median 41) after transplant, 10 in continued complete remission, one in haematological remission with residual marrow fibrosis and one with mixed haemopoietic chimaerism currently receiving therapy with interferon. Seven patients (six with AML/MDS and one with myelofibrosis) died of transplant-related complications. These data show that HSCT can provide curative therapy for patients with PV and ET with advanced disease.