14 Treatment of chronic myeloid leukaemia: some topical questions

Abstract

The treatment of chronic myeloid leukaemia has become extremely complex in recent years. Busulphan has been displaced by hydroxyurea where rapid control of the leukocyte count is required. It is generally accepted that interferon-α (IFN-α) prolongs life for those who achieve a major or complete cytogenetic response and it may also prolong life for those who achieve only a haematological response. Thus routinely most newly diagnosed patients are started on treatment with IFN-α alone or in combination with other agents and this agent is continued if possible for 2 or more years. Because allografting is the only way of curing patients with CML, those under the age of 50 or 60 years who have HLA-identical siblings should be offered treatment by allogeneic haemopoietic stem cell transplantation; however, the risks of morbidity and mortality remain appreciable. Transplants with stem cells from phenotypically HLA-matched donors should also be considered for younger patients. The role of autografting is not yet clearly established; a series of controlled studies comparing autografting with IFN-α have therefore been activated. Because patients usually retain in their blood and marrow substantial numbers of Ph-negative stem cells a variety of methods designed to favour collection in vivo or isolation in vitro of Ph-negative stem cells are currently under investigation. To integrate these different approaches to treating patients with CML in chronic phase a variety of algorithms or flow charts have been proposed but many of the criteria on which the recommended treatment decisions are based remain controversial or ill-defined.