Current myeloproliferative neoplasm scoring systems for clinical practice

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are clonal hematologic malignancies that are caused by the proliferation of myeloid cells that harbor a JAK-STAT pathway activating driver mutation. MPN management recommendations are based on the evaluation of different risks to prevent disease evolution-associated events while preserving patients' quality of life. Such risks can be common across all MPNs or specific to each subtype (polycythemia vera [PV], essential thrombocythemia [ET], prefibrotic myelofibrosis [MF], and primary MF). Patients with MF harbor the worse prognosis, and hematopoietic stem cell transplantation (HSCT) is the only curative treatment at the expense of a high rate of morbidity and mortality. Therefore, accurate scoring systems to estimate overall survival are crucial for the management of patients with MF and the selection for HSCT. In PV and ET, the prediction of vascular events is prioritized given their higher incidence and related morbidity and mortality. Finally, quality of life evaluation is important for all subtypes. To predict these risks and adapt MPN therapeutic strategies, clinical risk scores have been developed over the past decades and more recently have incorporated molecular risk factors for more accurate risk stratification. The large number of scoring systems available, combined with disease heterogeneity and the necessity to predict diverse outcomes, make it difficult for clinicians to choose the most appropriate score to evaluate their patients' risk in 2024. Here, we provide an overview of MPN disease evolution-associated event incidence and conduct an exhaustive comparative review of the scoring systems currently available for each risk. Finally, we propose an algorithm for the use of these scores in clinical practice in each MPN subtype.