Current myeloproliferative neoplasm scoring systems for clinical practice

BCR::ABL1-negative myeloproliferative neoplasms (MPN) are clonal hematological malignancies resulting from the proliferation of myeloid cells harboring 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 MPN or specific to each subtype (polycythemia vera (PV), essential thrombocythemia (ET), prefibrotic myelofibrosis (pre-MF), primary myelofibrosis (PMF)). MF-patients harbor the worse prognosis and hematopoietic stem cell transplantation (HSCT) is the only curative treatment, at the expense of a high morbi-mortality. Therefore, accurate scoring systems to estimate overall survival are crucial for MF patients' management and selection for HSCT. In PV and ET, vascular events prediction is prioritized given their higher incidence and related morbi-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, more recently including molecular risk factors for more accurate risk stratification. The large number of scoring systems available in combination 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 events 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.