Disease progression in myeloproliferative neoplasms: comparing patients in accelerated phase with those in chronic phase with increased blasts (10) or with other types of disease progression

摘要

Development of bone marrow (BM) fibrosis and transformation to accelerated/blast phase are the main forms of disease progression in myeloproliferative neoplasms (MPN). Chronic myeloid leukemia, -positive has several well-defined criteria that qualify for a diagnosis of accelerated phase (AP) disease according to the updated World Health Organisation (WHO) Classification. However, the only WHO criterion for diagnosing AP negative MPN is the presence of 10-19% blasts in the BM and/or peripheral blood (PB). Clinical characteristics and outcomes of patients with increased blasts falling below the 10% cut-off are not well-known. Prognostic schemes such as the International Prognostic Scoring System (IPSS) and the dynamic prognostic model (DIPSS), which are used to estimate survival and risk of leukemic transformation in MPN patients, include presence of ≥1% circulating blasts to predict disease progression. Other schemes have suggested circulating blast cut-offs of 2% or 3%. However, the current WHO classification that forms the basis for the pathology practice does not take into account increased blasts when they fall short of 10%.