Characterization of Myeloproliferative Neoplasms

Harry P. Erba, MD, PhD: Hello, and welcome to this OncLive® Peer Exchange®, titled “Updates in the Management of Myeloproliferative Neoplasms.” I am Dr Harry Erba from Duke Cancer Institute. Joining me today in this virtual discussion are my colleagues Dr Krisstina Gowin from the University of Arizona Cancer Center; Dr Ruben Mesa from the University of Texas Health San Antonio MD Anderson Cancer Center; Dr Jamile Shammo from Rush University Medical Center; and Dr Srdan Verstovsek from The University of Texas MD Anderson Cancer Center.

Today we are going to discuss a number of topics pertaining to the management of myeloproliferative neoplasms, including practical information for community oncologists. Let’s get started on our first topic. I’m going to turn to you, Dr Gowin, if you don’t mind. Krisstina, can you provide an overview of the myeloproliferative neoplasms?

Krisstina Gowin, DO: Absolutely. Good morning. Myeloproliferative neoplasms are a type of chronic myeloid malignancy that are characterized by overproduction of mature blood cells. They are characterized by a JAK2 V617F CALR nipple or other clonal mutations. They are also characterized, and this recently been described more eloquently over the last decade, by a very heterogenous symptom burden.

Harry P. Erba, MD, PhD: That’s great. There are various types. Those are similarities; how do we distinguish these?

Krisstina Gowin, DO: What’s interesting about myeloproliferative neoplasms is that it’s truly a spectrum of disorders. There’s a dynamic nature within the different umbrella of myeloproliferative neoplasms.

When we’re looking at these patients, we’re first asking if this is a classical myeloproliferative neoplasm or is there a Philadelphia chromosome involved, and that would be more diagnostic and a CML [chronic myelogenous leukemia]–type of picture. Within the classical myeloproliferative neoplasms, there are 3 different entities: polycythemia vera, myelofibrosis, and essential thrombocythemia. Polycythemia vera is classified based on a tri-lineage hematopoiesis, a very symptomatic splenomegaly, and a diffuse, heterogenous symptom burden.

Myelofibrosis, in contrast, is more of a fibrosis: scarring of the bone marrow that can lead to more of a cytopenic phase, rather than the hyperproliferative phase that we see with polycythemia. You can get this cyto-proliferation, this high burden of both white blood cells and platelets within myelofibrosis, as well. They tend to be more symptomatic and have a worse associated prognosis.

Finally, essential thrombocythemia is characterized by increased thrombocytosis as well as a very significant symptom burden. The treatment goals are different within these categories in that, for both polycythemia vera and essential thrombocythemia, it’s looking at the thrombotic and hemorrhagic complications of the disease; in myelofibrosis, we’re focusing more on spleen reduction and symptom burden.

Transcript Edited for Clarity