Evaluation of the need for cytoreduction and its potential carcinogenicity in children and young adults with myeloproliferative neoplasms

In a study of 643 patients with essential thrombocythemia and 347 patients with polycythemia vera—all children and adults younger than age 39 with newly diagnosed disease—the 5-year cumulative incidence of thromboembolic events (TEs) was 14.2% and 21.3%, respectively.

The incidence of arterial TE and venous TE was 12.6% and 0.7% in the ET group and 18.9% and 12.6% in the PV group, respectively. The 5-year cumulative incidence of second primary malignancies (SPMs) was 2.5% in ET and 2.6% in PV. The authors conclude that while cytoreduction may be needed for thrombosis prevention, there may be an increased risk of SPM with hydroxyurea use and this should be considered prior to starting therapy.