• Abdominal discomfort in people with myeloproliferative neoplasms (MPNs) is usually caused by an enlarged spleen, known as splenomegaly.
• Symptoms like bloating or abdominal pain may also be caused by unrelated conditions, such as acid reflux or irritable bowel syndrome. It is important to talk to your doctor to identify the cause and find the right treatment.
• There are several treatments available to help manage symptoms of an enlarged spleen in people with MPNs.

Myeloproliferative neoplasms are a type of blood cancer that starts in the bone marrow. In healthy people, the bone marrow produces normal blood cells at healthy rates. In MPNs, the bone marrow malfunctions, often producing one or more types of abnormal blood cells in excess. The three classic types of MPN are:

• Polycythemia vera (PV), which involves red blood cell overproduction
• Essential thrombocythemia (ET), which involves platelet overproduction
• Myelofibrosis (MF), in which bone marrow is replaced with scar tissue, disrupting blood cell production

Myelofibrosis can be primary or secondary — when PV or ET develop into MF.

One of the common symptoms of MPNs is abdominal discomfort. You might lose your appetite, feel full without eating very much (a symptom known as early satiety), or have pain in the abdomen or under your ribs. This abdominal discomfort is especially common on the left side of the body. These symptoms may lead to unwanted weight loss.

To learn more about what causes abdominal discomfort and how it is treated for people with MPNs, myMPNteam talked with Dr. Gabriela Hobbs, a leukemia specialist at Massachusetts General Hospital. Hobbs completed her fellowship training in hematology and oncology at Memorial Sloan Kettering Cancer Center in New York. Her research interests involve developing therapies for MPNs through clinical trials and collaboration with investigators in the laboratory.

What Causes Abdominal Discomfort With MPNs?

Dr. Hobbs explained the source of abdominal discomfort in MPNs is usually the spleen. The spleen is an organ located on the left side of the body, next to the stomach. Normally, new blood cells are produced in the bone marrow. If the bone marrow is affected by disease, for instance in someone with an MPN, the spleen can function as backup and take over production of new blood cells. If this happens, the spleen grows larger.

Your spleen also acts as a filter for blood, removing old or abnormal cells from the bloodstream. MPNs can cause the spleen to become abnormally large, a condition called splenomegaly. Up to 90 percent of people with MF have splenomegaly at the time of their diagnosis.

“Outside of splenomegaly, MPN shouldn't really be causing a tremendous amount of abdominal pain,” said Dr. Hobbs. “That's not a common or typical symptom if the spleen is not involved.”

Dr. Hobbs explained that abdominal discomfort can also be caused by health conditions unrelated to MPN, such as acid reflux or irritable bowel syndrome. It’s important to speak with your health care professional about your symptoms to help determine the cause and get proper treatment. As Dr. Hobbs said, “You’re not just a person with an MPN, you're a person who has a whole body. It's important to not ignore that.”

What Does Splenomegaly Feel Like?

In splenomegaly, the enlarged spleen can compress the stomach, decreasing appetite and causing you to feel bloated and full. An enlarged spleen is the usual source of abdominal discomfort caused directly by MPNs.

Splenomegaly can also cause or worsen related symptoms, such as tiredness, shortness of breath, pruritus (itching), night sweats, infections, and easy bruising.

Treatments for Splenomegaly

There are several treatment options for splenomegaly that can shrink your spleen and potentially reduce your abdominal symptoms and improve your quality of life.

Medications

There are medications developed to treat splenomegaly and its symptoms. “For people with MF, if they have a spleen that is bothersome, we usually start Jakafi (Ruxolitinib) to help reduce the size of the spleen,” Dr. Hobbs explained. Jakafi is a Janus kinase (JAK) inhibitor that targets the JAK-STAT signaling pathway — a mechanism inside cells that is disrupted in MPNs. Jakafi tablets are approved by the U.S. Food and Drug Administration (FDA) as a first-line treatment for several types of MF, including intermediate- or high-risk MF in people with bothersome splenomegaly symptoms.

For people with PV and splenomegaly, Dr. Hobbs explained the first-line treatments are generally hydroxyurea or interferon. Hydroxyurea is a chemotherapy drug that works by killing excess cells. There are different brands of hydroxyurea, but all forms are taken orally as capsules or tablets. Interferons are a natural part of the immune system. During interferon treatment, extra interferons are administered to boost the immune response — a type of immunotherapy. Interferon is given as a subcutaneous injection.

According to Dr. Hobbs, “If people with PV don't have a response with those medications, then Jakafi is approved as a second-line treatment. We can also use that to help improve the size of the spleen and symptoms.”

Phlebotomy

Phlebotomy, a procedure in which blood is drawn to reduce excess red blood cells, can decrease the risk of having a blood clot associated with PV. Phlebotomy is a temporary treatment. In one study involving 2,510 people with PV, those who underwent phlebotomy did so approximately eight times a year.

Radiation

External beam radiation, in which beams of X-ray energy are delivered to a site in the body, can be used to reduce the size of the spleen. However, its effects don’t last. “Radiation is something that really is just a temporary fix, if it works at all,” Dr. Hobbs said. “When it does work, it really only works for a short period of time, maybe for months. We do it to control symptoms when we don't have other options, understanding that it's not going to work for very long.”

Dr. Hobbs explained that radiation may be a good option to treat splenomegaly before a stem cell transplantation procedure, sometimes referred to as a bone marrow transplant. “When we treat people with MF who are ready for a bone marrow transplant, we might apply radiation to the spleen right before the transplant occurs,” she said. “This can help the bone marrow start working more quickly after the transplant. Sometimes it's harder for new bone marrow to kick in and start producing new blood cells if it's distracted by a big spleen.”

Splenectomy

In rare cases, the spleen can be surgically removed in a process called a splenectomy. However, Dr. Hobbs cautioned against this procedure, due to its risk factors. “Splenectomy is rarely done,” she said. “For people who have really big spleens, having a splenectomy actually can be associated with lots of complications, including blood clots in the abdomen. It’s something that we only do if we really have no other option.”

As with radiation, splenectomy is a better option for a person with MF who is planning to receive a stem cell transplant because the transplant will encourage normal blood cell production, reducing the need for a spleen. Otherwise, issues with blood production can occur.

“Remember, the spleen grows because it's trying to compensate for the bone marrow, which is where blood is normally made,” Dr. Hobbs clarified. “When you take away the spleen, people who aren’t going to get a transplant can have issues with having low blood counts.”

Easing Splenomegaly Symptoms

If you’re having trouble eating because splenomegaly makes you feel full easily, try eating several smaller meals and snacks throughout the day, rather than three large meals a day. Try drinking your liquids at separate times from your meals. Eating and drinking at the same time can make you feel full before you’ve gotten enough food or water.

If you have splenomegaly, you’re at increased risk of a ruptured spleen. Avoid strenuous activities that might involve hard contact — like football or soccer — and make sure to wear your seat belt when driving or riding in a car. Although it’s legally required to wear a seat belt, it’s even more important with splenomegaly because accidents could affect the spleen.

It’s also important to keep your vaccinations up to date. This includes your annual flu shot and any necessary boosters, as well as pneumonia and shingles vaccinations if your doctor has recommended these. If you’re concerned about possible side effects of vaccinations, speak with your doctor to make sure inoculations are safe for you.

You Are Not Alone: Finding Support for Abdominal Discomfort With MPNs

By joining myMPNteam, the social network and online support group for those living with MPNs, you gain a community of people who understand the challenges of living with these rare blood cancers.

Have you been affected by loss of appetite from an enlarged spleen? Has your doctor found the right treatment for your symptoms? Share your tips and experiences in a comment below or on myMPNteam. You'll be surprised how many other members have similar stories.