Survival in Primary (Idiopathic) Osteomyelofibrosis, so-called Agnogenic Myeloid Metaplasia

Abstract

A retrospective study was performed on 140 patients (58 males, 82 females) with primary osteomyelofibrosis/-sclerosis (OMF) or so-called agnogenic myeloid metaplasia in order to determine prognostic factors of predictive value. Considering the relatively high age at diagnosis (median age 66.5 years) the relative survival rates were calculated. According to the histological appearance of trephine biopsies taken on admission, our cohort of patients was divided into one group with an early hypercellular/-plastic stage with no relevant myelofibrosis (group I) and another revealing an advanced fibro-osteosclerotic subtype (group II). Factors that had an impact on survival included age, spleen and liver size and particularly the hemoglobin level. Estimation of survival rates displayed no significant differences between group I and group II patients.

Computation of the proportion of life lost due to OMF disclosed that in middle-aged patients excess risk of death ranged between 10 and 20 percent, contrasting with CML and AML which is about 80%. Variables indicative of an unfavorable prognosis in group I patients with an early stage of disease included moderate to gross splenomegaly and a manifest leuko-erythroblastic blood picture, i.e. evidence for myeloid metaplasia or bulky disease on admission. For this reason, extramedullary hematopoiesis already present at the clinical onset of disease without relevant myelofibrosis, is compatible with an expansion of an autonomous, neoplastic process and should not be regarded as compensation for a failing hypocellular central bone marrow compartment.

Key Words:

• Agnogenic myeloid metaplasia
• myelosclerosis
• myelofibrosis
• survival
• prognostic parameters