Myeloproliferative Neoplasms: Essential Thrombocythemia

Rami Komrokji, MD: Hello, and welcome to this OncLive® Peer Exchange titled “Current and Future Trends in Myeloproliferative Neoplasms.” I’m Rami Komrokji, the vice chair of the malignant hematology department at H. Lee Moffitt Cancer Center. I’m joined by a panel of my colleagues who treat myeloproliferative neoplasms. I’d like to welcome Dr Ruben Mesa.

Ruben Mesa, MD: Hello, Rami. I’m glad to be here. I’m Ruben Mesa. I’m the executive director of the Mays Cancer Center at UT Health San Antonio MD Anderson Cancer Center, and I’m delighted to have such wonderful friends and colleagues to be able to discuss the new updates from myeloproliferative neoplasms.

Rami Komrokji, MD: It’s always pleasure to see you. And Dr Jeanne Palmer.

Jeanne Palmer, MD: Hi, Rami. Thank you. I’m Jeanne Palmer. I’m from Mayo Clinic in [Phoenix,] Arizona. I’m the vice chair of the Division of Hematology and Oncology.

Rami Komrokji, MD: Excited to have you. And Dr Shammo.

Jamile Shammo, MD, FACP, FASCP: I’m Jamile Shammo. I’m a professor of medicine and pathology at Rush University Medical Center [in Chicago, Illinois].

Rami Komrokji, MD: Welcome. Let’s get started. We’re discussing a group of diseases: myeloproliferative neoplasms. Those are chronic myeloid neoplasms and blood cancers that have common clinical features and common pathophysiology. The whole mark for the disease is the activation of the JAK-STAT pathway that leads to an array of constitutional symptoms, including splenomegaly.

Myeloproliferative neoplasms are a spectrum of diseases. In this discussion, we’re going to focus mostly on ET [essential thrombocythemia], PV [polycythemia vera], and myelofibrosis [MF]. There have been recent advances in the understanding of those diseases and how to treat those patients. Those diseases have a magnitude of effect on our patients in terms of symptom burden and short-term complications, and they may impact the survival for our patients. We’re making progress, and I’m excited to share some of those results. We’ll start by talking about essential thrombocythemia and have Jeanne focus on it a little. How do we make the diagnosis? What is ET?

Jeanne Palmer, MD: Thank you. Essential thrombocythemia is a disorder where there are too many platelets, essentially. Generally patients will present with an elevated platelet count and they get sent to hematology. Once you’ve ruled out all the other causes of thrombocytosis, you can make the diagnosis of essential thrombocythemia. Eighty percent of them will have a driver mutation present, whether it be JAK2, MPL, or calreticulin. Looking for those mutations can help, but there are 20% of patients who won’t have one of those driver mutations present. Therefore, if there’s an index of suspicion, we prefer doing a bone marrow biopsy. Even if we have that diagnosis based on a driver mutation, a bone marrow biopsy is also indicated because these patients can sometimes have prefibrotic myelofibrosis or even overt myelofibrosis and the only presenting sign is thrombocytosis.

Rami Komrokji, MD: Absolutely. It’s very important to distinguish between prefibrotic MF and ET because it has prognostic implications. Hopefully we’re going to be treating those patients differently in the future.

Transcript edited for clarity.