Closer Monitoring Needed in Younger Patients with MPNs

Even though myeloproliferative neoplasms (MPNs) are more common in patients aged 60 or older and are thought to be less serious in younger patients, individuals who are younger than 25 should still be carefully monitored, according to research presented at the 2018 American Society of Hematology (ASH) Annual Meeting.

“MPNs are rarely identified in children and young adults, so complication rates and long-term data are lacking,” the researchers wrote in an abstract presented at the meeting, held Dec. 1 to 4, in San Diego. “These patients are often considered as low-risk patients because of their age or the supposedly lower rate of thrombosis.”

To address the lack of information on this younger subset of patients, an international team of researchers analyzed a large dataset from 29 hospital centers in 12 countries, collected between 1971 and 2018. Their retrospective review examined the data of 335 patients who were younger than 25 at the time of diagnosis.

The median age of all patients was 20.3 years, and the majority of patients in this study were female (73.4 percent). When examining the specific types of MPNs each individual was diagnosed with, 234 patients had essential thrombocythemia (69.8 percent), 60 had polycythemia vera (17.9 percent) and 41 had either myelofibrosis or an unclassified MPN (12.3 percent).

At diagnosis, 93 patients (27.8 percent) presented with hyperviscosity, 53 patients (15.8 percent) with abnormal spleen enlargement, and 44 (13.1 percent) reported fatigue. To assess their diagnosis, 214 patients (63.9 percent) had a bone marrow biopsy while 158 (47.2 percent) had bone marrow aspirates.

In analyzing the complications patients experienced, researchers found thromboses in 31 patients (9.3 percent) — 75 percent of which were venous – and 13 (3.9 percent) suffered from hemorrhage.

The median follow-up was 7.7 years, where 134 patients (40 percent) were followed for more than 10 years. During this time, 295 patients (88 percent) received at least one drug to treat their MPN: 254 (77.2 percent) received antithrombotic drugs and 222 (66.5 percent) received cytoreductive drugs.

Throughout their treatment, 97 patients (29 percent) experienced at least one complication, with thrombotic events being the most common. Hemorrhagic events occurred in 34 patients (10.1 percent).

The disease evolved in 39 patients (11.6 percent), with 11 patients (28.2 percent) evolving from essential thrombocythemia to polycythemia vera, 26 (66.7 percent) evolving into myelofibrosis and two (5.1 percent) developed into acute myeloid leukemia. Four deaths were recorded.

Overall, the researchers stated that the analysis of this large cohort of patients confirmed several facts. Despite their youth, most patients (88 percent) received drug(s) for the management of their disease, and the 29 percent incidence of complications was high. Additionally, vascular events and disease evolution occurred equally as often.

This led the team to recommend vigilance when monitoring the disease in patients under 25 years of age. “No specific national or international guidance exists for MPN patients of this age,” the authors noted, “but our data suggest that these are not benign conditions and patients need to be carefully followed and treated.”