Advanced Primary Myelofibrosis: Spleen Size and Treatment Approaches

In a Case-Based Roundtable for Targeted Oncology, Dr. Haris Ali, an associate professor with the City of Hope Department of Hematology and Hematopoietic Stem Cell Transplantation, discussed a case of primary myelofibrosis and touched upon subjects such as treatment considerations and the impact of spleen size. The case involved a woman aged 68 years who first reported symptoms of bruising, fatigue, and abdominal pain.

About Myelofibrosis

Myelofibrosis is considered a rare type of bone marrow cancer. The disease is characterized by the excessive accumulation of abnormal stem cells in the bone marrow which trigger a process called fibrosis, or scarring. Over time, the bone marrow is replaced with scar tissue. While the exact cause of myelofibrosis is not known, genetic mutations affecting the MPL, JAK2, and CALR genes are known risk factors. Symptoms of myelofibrosis include an enlarged spleen, anemia, shortness of breath, easy bruising and bleeding, greater risk of infection, bone pain, gout, fatigue, weight and appetite loss, and increased blood cell volume. As a cancer that affects stem cells, stem cell transplant can cure the disease. However, this process carries many significant risks. Other forms of treatment are symptomatic and supportive and do not alter the course of myelofibrosis. There is a dire need for safer and more effective therapies for the disease. To learn more about myelofibrosis, click here.

Guidelines for Managing High-Risk Disease

Dr. Ali says that the first step to managing high-risk primary myelofibrosis is to conduct an assessment of the patient’s signs and symptoms. This is typically conducted using MPN-10, a tool that consists of ten questions and can be scaled easily. He says that a transplant is the best option:

“Patients who have low platelets do poorly, so if they are transplant candidates, you proceed to transplant.”

With limited options currently available for this rare illness, Ali recommends the patients that don’t qualify for transplant should be considered for clinical trials. Other approaches include therapy using a JAK inhibitor. Some patients may progress to advanced disease or acute myeloid leukemia.

Ruxolitinib (marketed as Jakafi) is the only approved therapy for the disease, gaining this status in 2012. 

The spleen may become enlarged in some patients and splenectomy (removal of the spleen) has been used as a treatment in the past. However, Dr. Ali notes that most patients won’t benefit from this approach. He says that he would only consider this procedure in patients with low-risk disease, an enlarged spleen, and poor response to JAK inhibitor treatment. 

Spleen enlargement can cause anemia, and Ali says that these patients are often positive for the CALR mutation. Dr. Ali also says that spleen size can affect outcomes of transplants because of cytopenia. In patients with a spleen size greater than 20 cm, physicians should consider splenectomy or a myeloablative regimen.

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