Signs that myelofibrosis is progressing: What to watch for

Table of contents:

• Signs that myelofibrosis is progressing
• Recognizing early and advancing signs of myelofibrosis
• What your doctor looks for
• Treatment implications
• Living with progressing myelofibrosis
• When to seek urgent care
• Frequently asked questions
• Supporting those diagnosed with myelofibrosis
• Blood Cancer United myelofibrosis research impact
• Conclusion
• Sources

Myelofibrosis is a rare type of blood cancer—a chronic bone marrow disorder where scar tissue builds up and disrupts the body’s ability to produce healthy blood cells (Mayo Clinic, 2022). Over time, signs and symptoms can change, and knowing what to look for can help you and your care team adjust your treatment plan when needed. 

Everyone’s experience with myelofibrosis is different. Some people notice changes right away, while others may go years without any major signs. That’s why it’s helpful to know the potential warning signs and check in regularly with your care team. 

At Blood Cancer United, we provide support and services for all blood cancers—including myelofibrosis—with trusted and up-to-date information every step of the way. This page outlines some of the most common signs that myelofibrosis may be progressing, so you can find the information that’s most helpful to you.

Recognizing early and advancing signs of myelofibrosis 

Early signs to know 

In the early stages, signs of myelofibrosis may be subtle and easy to dismiss or attribute to more common causes like stress or aging. You might not feel very sick, and symptoms can be mistaken for everyday health issues. Common early signs include: 

• Persistent fatigue that leaves you feeling unusually tired during normal activities.
• Drenching night sweats that soak clothing and bedding.
• Unintentional weight loss, often noticed by looser-fitting clothes.
• Feeling lightheaded or shortness of breath during everyday activities—often due to a drop in red blood cell levels, an early sign of anemia.

Progression red flags 

When myelofibrosis is progressing, more pronounced and specific signs emerge: 

• Deep, aching bone pain often intensifies, signaling marrow expansion against fibrotic tissue.
• An enlarged spleen (splenomegaly) can produce abdominal discomfort or a sense of fullness even when little or no food is consumed.
• Worsening fatigue, dizziness, or shortness of breath during mild activity—these can reflect a significant drop in red blood cells, even if you haven’t been told you have anemia. Regular blood work (like a complete blood count, or CBC) can detect these changes before they become noticeable.
• Frequent infections, fevers, or easy bruising—these can be signs that your immune system or clotting ability is weakened, which may be due to low white blood cell or platelet counts. You might also notice prolonged bleeding from small cuts, bleeding gums, or tiny red or purple spots on your skin, called petechiae. 

These signs often signal that the disease is entering a more active or advanced stage. Let your healthcare team know about any changes, big or small, so they can adjust your care as needed.

What your doctor looks for

To track how myelofibrosis is progressing, doctors use a few different tools. First, they run blood tests to check for changes in key levels, such as a drop in hemoglobin (which can cause fatigue), an increase in white blood cells, or a decrease in platelets—all of which may suggest the disease is getting worse.

 In addition to blood tests, your doctor may also consider how you're feeling and whether any new or worsening symptoms are emerging, like fatigue, night sweats, or unintended weight loss. These clinical signs, when combined with lab results, give a more complete picture of how the disease may be changing over time. 

Doctors also use genetic tests to look for common mutations linked to myelofibrosis, including JAK2, CALR, and MPL. These mutations can offer clues about how the disease might behave and influence which treatments may be most effective. 

Finally, your doctor may use risk scoring systems to estimate how the disease is likely to progress. These tools take into account factors like your age, blood counts (e.g., low platelets, anemia), the presence of immature “blast” cells in the blood, and symptoms such as fevers, weight loss, or night sweats. Some systems also include genetic markers or chromosomal abnormalities. The more risk factors present, the more likely the disease is to progress more aggressively. Understanding your risk level helps your care team tailor a treatment plan—and may help determine whether more intensive options, like stem cell transplant, should be considered.

Treatment implications 

Adjusting or starting new treatments 

As your doctor learns more about how your myelofibrosis is behaving—and how your body is responding—your treatment plan may change. This is a common and expected part of managing the disease. Sometimes adjustments are made to better control symptoms, respond to new test results, or explore new options as they become available. 

While current treatments can help manage symptoms and improve quality of life, they don’t cure myelofibrosis or stop it from progressing over time. Eventually, some patients may stop responding to a treatment or develop signs that the disease is becoming more aggressive. When this happens, doctors may reassess the treatment plan and consider additional options based on the patient’s risk level, overall health, and treatment goals. 

One of the most common treatments for myelofibrosis is a class of medications called JAK inhibitors. These drugs work by calming an overactive signaling system in the body that can lead to inflammation, enlarged organs, and other symptoms. This signaling system is often affected by a mutation in a gene called JAK2, which is found in many people with myelofibrosis. JAK inhibitors like ruxolitinib help reduce spleen size and relieve symptoms like fatigue, night sweats, and bone pain (Bhave, Rupali, and Mesa, 2023). 

A person considered high risk due to rapid blood count changes or high molecular risk may be evaluated for an allogeneic stem cell transplant, the only curative option currently available (Mayo Clinic, 2022). However, because this procedure carries serious risks—such as infections, organ damage, or graft-versus-host disease (GVHD), where the donor’s immune cells attack the recipient’s body—it is typically reserved for younger, healthier individuals who are more likely to tolerate the transplant. These risks are especially concerning for older adults or people with other health conditions like heart, lung, or kidney problems, which can make recovery more difficult (Blood Cancer United, 2025). 

Because of the complexity and risks involved, the decision to move forward with a stem cell transplant is made carefully and often involves a team of specialists. Doctors consider not just a patient’s age and overall health, but also how quickly the disease is progressing and whether there is early evidence of organ damage. 

Timing is critical: younger patients or those who are still physically active and able to manage daily tasks without significant help tend to benefit most from a transplant, especially if it happens before the disease causes more advanced organ damage.

Symptom Management Strategies 

Palliative care plays a central role in managing myelofibrosis symptoms. Blood transfusions can help treat severe anemia, while medications that stimulate red blood cell production—known as erythropoiesis-stimulating agents—may help maintain healthy hemoglobin levels over time. Discomfort from an enlarged spleen can often be managed with low-dose radiation or hydroxyurea, a medication that helps shrink the spleen. To manage fatigue, patients may benefit from lifestyle changes like prioritizing daily tasks, taking rest breaks, and participating in light, structured exercise to improve energy levels and quality of life. 

Pain management, nutritional support, and treatment for night sweats can significantly improve daily living.

Living with progressing myelofibrosis

Maintaining quality of life involves more than medical interventions. Palliative care teams can assist with symptom control, psychosocial support, and advance care planning. Nutritional counseling, tailored exercise regimens, and strategies for coping with chronic fatigue all contribute to overall well-being. Mental health resources—counseling or support groups—offer emotional support for the person diagnosed with myelofibrosis and their caregivers.

When to seek urgent care 

Certain symptoms warrant immediate medical attention, like sudden, severe bone or abdominal pain, uncontrolled bleeding, high fevers, or signs of infection (e.g., chills, cough). Because myelofibrosis may increase the risk of blood clots, be alert for sudden limb swelling, chest pain, or neurological deficits such as slurred speech or weakness—signs that could indicate deep vein thrombosis, pulmonary embolism, or stroke (Blood Cancer United, 2025).

Frequently asked questions 

1. What are the warning signs that myelofibrosis is getting worse? Key warning signs include escalating bone pain, a rapidly enlarging spleen, worsening anemia (fatigue, shortness of breath), and recurrent infections or bleeding.
2. How fast does myelofibrosis usually progress? Progression varies widely. Some people experience fewer symptoms of the disease for years, while others may progress more rapidly based on clinical and genetic risk factors.
3. Can myelofibrosis suddenly get worse? Yes. In about 10–20% of patients, myelofibrosis can progress rapidly into a more aggressive form of blood cancer called acute myeloid leukemia (AML). This can cause people to feel significantly worse very quickly, with symptoms like severe fatigue, infections, bleeding, or a sharp drop in blood counts.
4. What is end-stage myelofibrosis like? End-stage myelofibrosis often involves a significant reduction in all types of blood cells (severe pancytopenia), and the body starts making blood cells outside the bone marrow, which is called extramedullary hematopoiesis. This can lead to clumps or tumors of developing blood cells in other parts of the body. These growths may cause serious complications such as bleeding in the digestive tract, coughing or spitting up blood, seizures, or spinal cord compression (Blood Cancer United, 2025). At this stage, hospice care may be considered to focus on comfort, dignity, and quality of life, especially when active treatment is no longer effective or appropriate.

Supporting those diagnosed with myelofibrosis 

Loved ones and caregivers play a vital role. Emotional support, assistance with medical appointments, medication management, and help navigating treatment decisions can all make a significant difference. Encouraging open communication and learning about the disease through resources like the Blood Cancer United Myelofibrosis Overview helps families feel empowered.

Blood Cancer United myelofibrosis research impact 

Blood Cancer United is driving progress in understanding and treating myelofibrosis. Through targeted research funding, Blood Cancer United is accelerating discoveries that improve diagnosis, monitor disease progression, and lead to more effective treatment options. 

• Advancing research: ​​​​​​​​​Funds studies to uncover how myelofibrosis progresses and may transform into acute leukemia. These efforts aim to identify early warning signs through genetic and biological markers, allowing for earlier and more effective intervention.
• Empowering patients through education: Blood Cancer United offers up-to-date, accessible information and support to help patients recognize signs and symptoms of progression and understand when to consult their care team.
• Policy and advocacy: Blood Cancer United's Office of Public Policy (OPP) advocates for policies that accelerate the development of new treatments for myelofibrosis and help remove the barriers patients often face in accessing timely care, diagnostics, and emerging therapies.
• Developing better treatments: Blood Cancer United supports the development of new therapies, including clinical trials exploring innovative drug combinations that target the disease more effectively. You can also connect with a Blood Cancer United information specialist to discuss symptom management, request a nutrition consultation, or get guidance tailored to your unique situation. 

Your support powers this life-changing work, bringing us closer every day to better treatments and cures for leukemia, lymphoma, and related blood cancers like myelofibrosis.

Conclusion 

Recognizing the signs that myelofibrosis is progressing enables timely intervention and enhances quality of life. With the combined support of healthcare teams, palliative care, and Blood Cancer United resources, individuals and their loved ones can navigate this cancer with greater confidence and hope.

About the author: Dr. Ali is a medical journalist and copywriter.

Sources

Mayo Clinic. “Myelofibrosis - Symptoms and Causes,” n.d. https://www.mayoclinic.org/diseases-conditions/myelofibrosis/symptoms-causes/syc-20355057. 

Daniel A. Arber et al., “International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: Integrating Morphologic, Clinical, and Genomic Data,” Blood 140, no. 11 (June 29, 2022): 1200–1228. https://doi.org/10.1182/blood.2022015850. 

Passamonti F, Mora B. “Myelofibrosis.” Blood. 2023;141(16):1954–1970. https://doi:10.1182/ blood.2022017423.

Bhave, Rupali R., Ruben Mesa, and Michael R. Grunwald. “Top Advances of the Year: Myeloproliferative Neoplasms.” Cancer 129, no. 23 (September 28, 2023): 3685–91. https://doi.org/10.1002/cncr.35028. 

Blood Cancer United. Myeloproliferative Neoplasms: In Detail, 2025. https://llsorg.widen.net/view/pdf/juiq8xkd2b/en-booklet-mpn-detail-ps81.pdf?t.download=true&u=swuzoq.