Splenectomy in chronic myeloid leukemia and myelofibrosis with myeloid metaplasia

Myelofibrosis with myeloid metaplasia (MMM) is a collective term that descr ibes the related disorders AMM, PPMM, and PTMM. The chronic myeloid disorde rs include chronic myeloid leukemia, polycythemia vera, essential thrombocy themia, and agnogenic myeloid metaplasia (myelofibrosis). These disorders d isplay varying propensities for pathologic enlargement of the spleen which can lead to mechanical discomfort, hypercatabolic symptoms, anemia, thrombo cytopenia, and portal hypertension. Splenectomy has been found to be of lit tle benefit in the early stages of chronic myeloid leukemia. Similarly, the benefit of splenectomy in advanced cases is limited to symptomatic palliat ion and treatment of delayed engraftment after allogeneic bone marrow trans plantation. Although polycythemia vera and essential thrombocythemia are al so characterized by splenomegaly, splenectomy is not considered a therapeut ic option in the absence of transformation of the disease into myelofibrosi s with myeloid metaplasia. Splenectomy has been studied most in myelofibros is with myeloid metaplasia. Although there is no clear survival advantage t o splenectomy in this disorder, the surgical procedure can result in substa ntial palliation of mechanical discomfort, hypercatabolic symptoms, portal hypertension, and anemia. However, the procedure is associated with an appr oximately 9% mortality rate, and the postsplenectomy occurrence of extreme thrombocytosis, hepatomegaly, and leukemic transformation is of major conce rn. (C) 2000 Harcourt Publishers Ltd.