[Clinical characteristics of adolescents and young adults, and the relationship between neutrophil count/ratio and thrombosis in Japanese patients with polycythemia vera and essential thrombocythemia: sub-analyses of JSH-MPN-R18].

Abstract

This review focuses on the findings of the JSH-MPN-R18 study, a retrospective analysis of 596 patients with polycythemia vera (PV) and 1,152 patients with of essential thrombocythemia (ET). Among the four sub-analyses conducted, one focused on adolescents and young adults (AYA population) with PV and ET, demonstrating that the characteristics of thrombotic events in young Japanese patients differ from those observed in Western populations. Specifically, the proportion of venous thrombosis among all thrombotic events was lower in the Japanese AYA population compared to their Western counterparts. Additionally, an analysis focusing on absolute neutrophil count and neutrophil ratio at diagnosis revealed their utility as predictors of thrombotic events, particularly in low-risk ET patients. These findings should contribute to the development of appropriate management strategies for young PV and ET patients in Japan, as well as to the enhancement of thrombotic risk stratification for PV and ET patients overall.