Ask the Experts – Maureen Thyne

Ask the Experts

Polycythemia Vera

Maureen E. Thyne, RPA-C

Practice Community
New York, New York

Hospital and Institutional Affiliations
Weill Cornell Leukemia Program at Weill Cornell Medicine and NewYork-Presbyterian
Oncology Nurse Advisor (ONA): What is the role of phlebotomy in the treatment of patients with polycythemia vera (PV)?
Ms Thyne: Polycythemia vera is a condition where the bone marrow makes too many cells — this extra production typically involves the red blood cells, but may also involve the white blood cells and/or platelets. One of the ways to treat patients with PV is to use phlebotomy to remove some of the excess cells from circulation. This is particularly useful when a patient is first diagnosed (when the blood counts would be expected to be high) and sometimes periodically throughout the year. This helps remove the extra cells from circulation, but ultimately doesn’t change what’s being produced in the bone marrow. Often, an additional treatment (usually medication) is used to try to lower the blood counts and make the need for phlebotomy minimal.
ONA: What options are available if phlebotomy does not provide adequate hematocrit control?
Ms Thyne: If the patient is needing more than an occasional phlebotomy to manage the blood counts, medication options are usually discussed. At this time, the two most common treatments are hydroxyurea or interferon. The goal of these therapies is to lower the blood counts so that the patient no longer needs phlebotomy. These medications work differently, and there are different potential side effects, so patients should discuss what’s best for them with their health care team.
ONA: What are the signs and/or symptoms that indicate the patient may have persistent disease or is intolerant to treatment? What are your tactics for monitoring patients from diagnosis and throughout treatment?
Ms Thyne: Sometimes the blood counts remain poorly controlled even with medication, and the patient continues to require phlebotomy. Other times, some of the symptoms of the disease may not improve, such as itching, night sweats, or an enlarged spleen. These scenarios may indicate that the disease is resistant to the chosen medication. Sometimes the medication is almost “too successful” in reducing the blood counts, meaning it might lower the red blood cells perfectly and eliminate the need for phlebotomy, but might lower one of the other blood counts (white blood cells or platelets) too much, leaving the patient at risk for complications. In other cases, the medication may cause side effects making it difficult or impossible to continue taking. These are examples of a patient being intolerant to the medication. In both of these situations (disease that is resistant to the first choice medication, or an issue of intolerance to that medication) a change in medication therapy might be indicated. Again, this should be discussed with the patient and their health care team.

Regardless of what type of treatment plan a patient is on, it’s important to closely monitor the lab work. Depending on the patient, this may be as often as weekly, or may only be every few months. It’s also important to establish good communication between the patient and the provider, so they can regularly review and discuss any new or changing symptoms, whether they are related to the disease or the treatment. Other health maintenance should be reviewed and kept up to date as well, such a screening tests like mammogram and colonoscopy, dermatology skin exams, and vaccines like flu and pneumonia. Patients with chronic diseases can be at different risk than the general population, and it’s important to review and discuss these recommendations.
ONA: What are the risks for patients with persistent/intolerant PV?
Ms Thyne: PV is part of a group of diseases of the bone marrow called myeloproliferative neoplasms (MPNs). The extra blood cell production that characterizes these diseases can lead to more serious conditions, like myelofibrosis or even acute myeloid leukemia. There are also risks of secondary issues, like blood clots, which may be higher if the blood counts are not well controlled. Although each of these examples are rare, it’s important to have long-term, careful monitoring and to understand the risks.
ONA: What are the criteria for initiating treatment with ruxolitinib in patients with PV? Do you follow a particular protocol to identify appropriate patients?
Ms Thyne: Currently, for PV patients, ruxolitinib is approved by the U.S. Food and Drug Administration as second-line therapy for those who have resistance or intolerance to hydroxyurea. This means if the patient is having well-controlled blood counts and well-managed disease symptoms and no ill effects while taking hydroxyurea, they should continue this treatment plan. However, if the hydroxyurea is not sufficient at controlling the blood counts and the patient is still requiring phlebotomy; or if the patient is having intolerable side effects of hydroxyurea; or if the hydroxyurea has controlled the red blood cells but caused other blood counts to become unnecessarily low, these patients would be eligible to consider treatment with ruxolitinib. As with all treatment decisions, the patient should thoroughly review the potential risks and benefits associated with this and all other therapeutic options and make an informed decision with their health care team.