An analysis based in Japan identified differences in clinical characteristics between adolescents and young adults (AYA) and the non-AYA population among those with polycythemia vera (PV) or essential thrombocytopenia (ET). Findings were reported in the International Journal of Hematology.
The study was a large-scale retrospective analysis of AYA patients (aged 20 to 39 years) in the Japanese JSH-MPN-R18 registry who had been seen for an initial visit for PV or ET between April 2005 and March 2018. The study investigators evaluated clinical characteristics associated with PV or ET in this AYA cohort to increase understanding of myeloproliferative neoplasms (MPNS) in this population, in comparison with non-AYA patients from the registry.
In the registry, a total of 596 patients with PV and 1152 patients with ET were identified. There were 31 AYA patients among those with PV and 141 AYA patients among those with ET, corresponding to 5.2% of the total patients with PV and 12.2% of those with ET. In the AYA cohort, the median age at diagnosis was 33 years with PV and 32 years with ET.
AYA patients with PV had a lower median neutrophil ratio (71%) than non-AYA patients with PV did (78%; P <.01). Their median neutrophil count (6.5 x 109/L) was also lower than in the non-AYA population with PV (9.238 x 109/L; P =.03).
Among patients with ET, the AYA cohort showed lower values than non-AYA patients did for numerous parameters, such as median leukocyte count, neutrophil ratio, neutrophil count, lactate dehydrogenase level, and D-dimer level (P <.01 each). Palpable splenomegaly was also more common among AYA than non-AYA patients in the ET group (6.3% vs 2.3%, respectively; P =.02).
In patients with ET, the 5-year rate of hemorrhage-free survival (HFS) was higher for AYA patients (100%) than for non-AYA patients (93.9%; P <.01). For patients with PV, HFS did not significantly differ between AYA and non-AYA patients.