Prognostic significance of bone marrow biopsy in essential thrombocythemia

Abstract

BACKGROUND AND OBJECTIVE: The diagnostic and prognostic value of bone marrow biopsy (BMB) has been widely investigated in patients with chronic myeloproliferative disorders (CMPD). The present study is based on a review of the results of routine BMBs taken from 93 essential thrombocythemia (ET) patients at the time of diagnosis. DESIGN AND METHODS: The common BMB histologic parameters and clinico-hematologic variables were considered for diagnostic and prognostic purposes. Clinico-pathologic correlations were looked for univariately. Moreover, the diagnostic significance of the histologic findings was tested by means of cluster analysis. Overall survival and event-free survival were considered as prognostic endpoints. RESULTS: There were no correlations between the clinic and pathologic findings, and none of the histologic and clinical parameters was predictive of survival or the occurrence of major clinical events. Cluster analysis of the BMB findings revealed two distinct morphologic patterns: one was clearly myeloproliferative; the other had somewhat dysplastic features. The event-free and overall survival rates in the latter group were significantly worse (p = 0.0377 and p = 0.0162 respectively), with major ischemic events accounting for most of the difference in event-free survival. INTERPRETATION AND CONCLUSIONS: These results have no clearcut counterpart in the literature, but we feel that dysplastic BMB findings could be included in the definition of ET prognostic scores in order to allow therapeutic strategies to be adapted to the level of risk.