Hairy cell leukemia is a rare type of leukemia. There is currently no cure for hairy cell leukemia, but treatment options include watchful waiting, chemotherapy, targeted therapy, and more.

Just like other types of leukemia, hairy cell leukemia is a blood cancer. It occurs more often in men than in women. Only around 600 to 800 people in the United States are diagnosed with hairy cell leukemia each year. Most of them will go into remission after treatment.

Hairy cell leukemia is a rare form of leukemia. It happens when your bone marrow makes too many of a type of immature white blood cell called a lymphocyte. The cells multiply quickly and crowd out healthy white blood cells, red blood cells, and platelets. The lymphocytes gather in your bone marrow, liver, and spleen.

Hairy cell leukemia gets its name because the cancerous lymphocytes appear “hairy” when viewed under a microscope. Hairy cell leukemia can cause symptoms a lot like other types of leukemia, such as:

It might also cause some unique symptoms, including:

  • a feeling of fullness or pain below your ribs
  • painless lumps, which are swollen lymph nodes, in your neck, stomach, underarm, or groin

Hairy cell leukemia often grows slowly. It’s possible to have it for years without noticing any symptoms or needing treatment. When treatment does begin, it can include various options, which you can learn about next.

You don’t always need to start treatment right away. This is because hairy cell leukemia can progress slowly, or not at all. In this case, your doctor will want to monitor you in a phase called watchful waiting.

During this time you’ll have regular follow-up appointments. Your doctor will keep an eye on your symptoms and your blood work to determine if you need treatment. Most people will need treatment eventually.

Chemotherapy is typically the first treatment used to manage hairy cell leukemia. Many people with hairy cell leukemia go into partial or complete remission after chemotherapy treatment. Remission often lasts for several years.

There are two main chemotherapy drugs used to treat hairy cell leukemia:

  • Cladribine. This is the first chemotherapy drug most people with hairy cell leukemia will receive. You’ll usually receive this treatment through an intravenous (IV) line over the course of 7 days. Side effects may include fever and infection.
  • Pentostatin. Pentostatin works similarly to cladribine. You’ll generally receive it through an IV once every other week over a course of 3 to 6 months. Side effects can include infection, fever, and nausea.

You can generally receive a second round of chemotherapy if you don’t go into remission or if you experience a relapse, a return of the cancer.

You might also consider targeted therapy if your hairy cell leukemia doesn’t respond to chemotherapy or if it relapses.

Targeted therapy uses medications that cause cancer cells to become recognizable to your immune system. This allows your immune system to attack and kill the cancer cells more easily. It also usually causes less harm to your healthy cells than chemotherapy.

One targeted therapy medication used in treating hairy cell leukemia is rituximab (Rituxan). Rituximab is a type of medication called a monoclonal antibody. A monoclonal antibody is an immune system protein that can attach to cancer cells and block their growth.

Rituximab is generally given through an IV, and its side effects may include infection and fever. Sometimes you’ll receive rituximab along with chemotherapy to help you go into remission.

A few other targeted therapies are used in the treatment of hairy cell leukemia. For example, in 2018, the FDA approved the drug moxetumomab pasudotox (Lumoxiti) as a treatment for hairy cell leukemia. Lumoxiti and similar targeted therapies might be a good option if other treatments haven’t put your cancer in remission.

The main surgery used to treat hairy cell leukemia is a splenectomy, or a spleen removal. Your spleen might need to be removed if it’s causing you pain or if it’s become enlarged enough that it might rupture.

A splenectomy can help lower the number of cancerous cells in your bloodstream, but it’s not a cure for hairy cell leukemia. A splenectomy comes with its own risks, since it increases your chances of heavy bleeding and infection.

Doctors sometimes recommend clinical trials to people with hairy cell leukemia. Clinical trials are conducted to find new cancer treatments that might be safer or more effective than current options.

By taking part in a clinical trial, you might be the first to try a new treatment for hairy cell leukemia. You’ll also be helping to advance cancer research.

While there’s no cure at this time for hairy cell leukemia, treatments help most people reach remission. The Leukemia & Lymphoma Society says that the 5-year survival rate after a chemotherapy treatment using cladribine is 90 percent. Many people are able to stay in remission for over 5 years.

Your specific outlook will depend on how fast your hairy cell leukemia grows and how well it responds to treatment.

Hairy cell leukemia is a rare type of leukemia that generally grows slowly. There’s no cure for hairy cell leukemia, but effective treatment options can help most people reach remission. This remission often lasts years.

Treatment generally begins with chemotherapy and might move on to targeted therapy, if needed. If you have hairy cell leukemia, you can also participate in clinical trials to see if newly developed treatments can help get you to remission.