Brief overview
- Prognosis: With successful therapy, the prognosis is usually good and affected individuals usually have a normal life expectancy. In the hairy cell variant (HZL-V), the prognosis is somewhat worse due to limited treatment options.
- Causes: Triggers of this disease are not known. Experts suspect that chemical substances such as insecticides or herbicides play a role and increase the risk.
- Symptoms: General weakness, fatigue, decreased ability to work under pressure, pallor, bruising (hematomas), increased bleeding from the gums and nose, tendency to get infections, abdominal pain or pressure in the left upper abdomen due to an enlarged spleen, less commonly swollen lymph nodes, fever and night sweats
- Treatment: Chemotherapy is usually given with a single drug or a combination of drugs (cytostatics). If this does not work sufficiently, immunotherapy with special antibodies (also in combination as chemoimmunotherapy) sometimes helps. Alternatively, BRAF inhibitors are used.
- Examinations: The doctor performs physical examinations and takes a blood count. He also checks the function of the spleen using ultrasound and usually performs a bone marrow examination (tissue sample, bone marrow puncture).
What is hairy cell leukemia?
Hairy cell leukemia (HZL or HCL from “hairy cell leukemia”) is a chronic cancer. In patients, certain white blood cells (B lymphocytes) degenerate and begin to multiply uncontrollably.
Despite the name “leukemia”, HZL does not belong to the blood cancer diseases (leukemias), but to the lymphoma diseases (malignant lymphomas). Strictly speaking, hairy cell leukemia is classified as a non-Hodgkin’s lymphoma – as is chronic lymphocytic leukemia (CLL), among others.
Hairy cell leukemia is rare – it accounts for about two percent of all lymphatic leukemias. Only three out of one million people contract it each year. Most of these are men: they are up to four times more likely to be affected by hairy cell leukemia than women. The average age of onset is between 50 and 55 years. However, it sometimes also affects younger or older adults. Hairy cell leukemia only does not occur in children.
Physicians distinguish between the classic hairy cell leukemia and the hairy cell leukemia variant (HZL-V). The latter is much rarer and runs a more aggressive course.
What is the prognosis for hairy cell leukemia?
The prognosis is less favorable for the hairy cell leukemia variant (HZL-V). It is more aggressive than the chronic, insidious classic hairy cell leukemia. Current treatments usually do not work as well in HZL-V. In some cases, this shortens the survival time of those affected.
What causes HZL?
The causes of hairy cell leukemia are not known. Experts suspect that insecticides and pesticides (herbicides), among other things, promote the development of this form of cancer. People who work in agriculture appear to have an increased risk of developing the disease.
What are the signs of HZL?
Hairy cell leukemia is a chronic cancer that usually progresses slowly. Most people affected initially notice little of their disease for a long time. Gradually, the cancer cells (“hair cells”) displace the healthy blood cells, i.e., normal white and red blood cells and platelets, in most sufferers. In about 70 percent of all people with hairy cell leukemia, the number of all three types of blood cells is below their respective lower limit. Doctors then speak of pancytopenia.
Typical of hairy cell leukemia – in addition to the lack of healthy blood cells – is an enlarged spleen (splenomegaly). It is sometimes noticeable by a feeling of pressure in the left upper abdomen.
Rarer signs of hairy cell leukemia are an enlarged liver and swollen lymph nodes. Also rare are the three so-called B symptoms: Fever above 38 degrees Celsius, weight loss and night sweats. This trio of symptoms is common in cancer as well as in various infectious diseases.
What are the treatment options?
As long as hairy cell leukemia does not cause any symptoms and the number of healthy blood cells is not yet reduced, the motto is: Wait and see. At this stage of the disease, no therapy is necessary. Instead, the doctor regularly examines the blood of the patient (at least every three months).
If the blood cell readings drop and/or symptoms appear, it is recommended to start treatment. In most cases, the doctor initiates chemotherapy: Sufferers receive certain anti-cancer drugs (cytostatics) that inhibit the proliferation of cancer cells. In hairy cell leukemia, for example, the active ingredients cladribine (2-chlorodeoxyadenosine, 2-CDA) and pentostatin (deoxycoformicin, DCF) are used. They are among the so-called purine analogues.
One example is the active ingredient interferon-alpha. It inhibits the proliferation of cancer cells and activates immune system defense cells. Doctors inject the drug under the skin several times a week, often for years. Doctors use interferon-alpha, for example, to treat patients who, for certain reasons, are not suitable for chemotherapy with purine analogues. The drug is also helpful in the event of a cancer relapse when chemotherapy is not effective or sufficient.
Another treatment option for hairy cell leukemia is immunotherapy with so-called monoclonal antibodies (such as rituximab). These are artificially produced antibodies that influence the body’s immune system: they bind specifically to the cancer cells, signaling the immune system’s defense cells to destroy the degenerate cell. The doctor administers rituximab directly into a vein every one to two weeks. He prescribes it for hairy cell leukemia when an affected person is not allowed to receive purine analogues (chemotherapy) and interferon-alpha or cannot tolerate them for medical reasons.
Sometimes it makes sense in hairy cell leukemia to combine chemotherapy (with purine analogues) and immunotherapy (with rituximab). Doctors then speak of chemoimmunotherapy.
Hairy cell leukemia variant
The very rare hairy cell leukemia variant (HZL-V) does not respond well to chemotherapy with purine analogs. Interferon-alpha is also not very effective. Chemoimmunotherapy (chemotherapy with purine analogues plus rituximab), for example, is more suitable. If a short-term relapse occurs, it is sometimes useful to remove the spleen (splenectomy). This often improves the cancer patient’s blood counts. Surgery is also recommended if a sufferer is not allowed to receive chemotherapy with purine analogues for medical reasons.
How is HZL examined and diagnosed?
In patients with typical symptoms, the physician first takes the patient’s medical history. He or she obtains a detailed description of the symptoms, asks about any previous or underlying diseases and whether the affected person has been exposed to toxic substances (such as insecticides).
This is followed by a thorough physical examination. Among other things, the doctor checks whether the lymph nodes (for example in the neck region or under the armpits) are swollen. He also palpates the abdominal wall to see whether the spleen is enlarged. This can be assessed more precisely with an ultrasound examination (sonography) of the abdomen.
The majority of patients have classic hairy cell leukemia. It is characterized, among other things, by a reduced number of lymphocytes (a form of white blood cell) and platelets. In the rare hairy cell leukemia variant, the situation is different: Here, the lymphocytes are significantly increased. The measured values for the blood platelets are usually normal.
Also important in hairy cell leukemia is an examination of the bone marrow: the doctor takes a sample of the bone marrow (bone marrow puncture) and analyzes it in more detail in the laboratory.
Can HZL be prevented?
Since the causes of this rather rare disease are unclear, there are no confirmed or effective measures for prevention.
