Hairy cell leukemia: causes, symptoms and treatment

Hairy cell leukemia or hairy cell leukemia is a cancer in which the patient's bone marrow produces too many B lymphocytes, a type of white blood cell typical of the adaptive immune response. Abnormal lymphocytes appear "hairy" under the microscope, hence the name of the pathology.

As the number of abnormal B lymphocytes increases in the blood, the proportion of healthy white blood cells, red blood cells and platelets decreases, with all the physiological effects that this entails. If you want to know the causes, symptoms and treatment of this disease, keep reading.

Who is at risk?

As an article published in Cancer Therapy Advisor, Hairy cell leukemia (or HCL, for its English translation Hairy Cell Leukemia) represents 2% of total leukemias, with an annual incidence of 1 case per 500,000 inhabitants. Men are much more prone to it; in particular 5 times more.

On the other hand, the average age of its appearance is 55 years. Thus, the typical patient is a middle-aged / elderly man with clinical signs such as fatigue, tiredness, and weight loss. According to the Mayo Clinic, there are 2 predisposing factors beyond gender and old age. These are the following:

  1. Exposure to radiation: People who work in radioactive environments or have undergone radiation therapy to kill cancer may be more likely to develop hairy cell leukemia. Even so, there is still no conclusive evidence of this.
  2. Exposure to chemicals: prolonged exposure to agrochemicals and industrial compounds could promote this pathology, although it has not yet been confirmed.

2% of leukemia cases correspond to hairy cell leukemia.

To learn more: Acute Lymphoid Leukemia: Treatments

What symptoms does hairy cell leukemia cause?

As we have said, hairy cell leukemia is a type of cancer that affects the blood and bone marrow. This usually progresses slowly or, failing that, does not get worse at all. As indicated by the National Library of Medicine of the United States, some of the most common clinical signs are the following:

  • Tendency to bruise or bleed. This is usually a sign of low blood platelets.
  • Profuse sweating, especially at night.
  • A feeling of abdominal fullness (enlarged spleen) which can make it a bit uncomfortable to eat at times or in large amounts. This can lead to unintended weight loss.
  • Recurrent infections and fevers, due to a weakened immune system.
  • Fatigue and tiredness
  • Lymphadenopathy, or what is the same, swollen lymph nodes.

As you can see, many of these clinical signs are typical of other pathologies. Therefore, this disease is usually diagnosed accidentally in a routine blood test.

Severe symptoms

Hairy cell leukemia progresses slowly and sometimes remains stable for several years without needing to be medically addressed. The survival rate 5 years after diagnosis is 90%.

However, untreated hairy cell leukemia can crowd out healthy white blood cells in the bone marrow and circulating red blood cells, leading to severe infections, anemia, and bleeding. They are secondary diseases to cancer that can become dangerous.

How is it diagnosed?

According to the magazine Leukemia & Lymphoma, there are different diagnostic methods that can help medical professionals diagnose hairy cell leukemia. These are the following:

  1. Physical exam and health history: swollen spleen, enlarged lymph nodes, or abnormal bruising can be seen on direct physical examination. Of course, this is not a confirmation of the disease in any case.
  2. Complete blood count (RSC): It is used to detect the number of red blood cells in the blood, which may decrease as the disease progresses.
  3. Peripheral blood smear: A small sample of the patient's blood is analyzed under a microscope. Here you can see the hair lymphocytes already described.
  4. Biochemical studies of blood, bone marrow aspiration and biopsy, genetic testing, computed tomography (CT) and other specific diagnostic tests.

Hairy cell leukemia treatments

It is not always necessary to begin treatment for hairy cell leukemia once it has been diagnosed. According to the National Cancer Institute, in non-symptomatic cases, the patient is carefully monitored to see if he develops clinical signs, although this may take a long time.

Once the condition described above develops, you can resort to chemotherapy (drugs that stop the formation of cancer cells), immunotherapy (the patient's own immune system is used to destroy the cancer) or surgery, such as removal of the spleen if necessary.

Targeted therapy is a very promising field against this disease.

In any case, before the administration of certain drugs (2-chlorodeoxyadenosine 2-CdA, pentostatin or interferon α), the 5-year survival rate for patients with advanced hairy cell leukemia is more than 85%. This means that, even in the most severe cases, death is not often thought of as safe.

If the doctor requires it, one of the treatment options is chemotherapy.

Development of hairy cell leukemia

A publication of Leukemia and Lymphoma Society shows us the development of the disease. It can be summarized in the following points:

  1. The cells that give rise to normal lymphocytes undergo an acquired mutation in their DNA, which promotes the formation of hairy lymphocytes instead of normal ones.
  2. Hair lymphocytes do not have immune capacity and accumulate in the bone marrow, liver and spleen, hence the latter sometimes have to be removed.
  3. Hair lymphocytes multiply in an uncontrolled way, which displaces the rest of leukocytes, erythrocytes and platelets.
  4. This results in a lack of red blood cells (anemia), a deficiency of white blood cells (neutropenia), and a lack of platelets in the blood (thrombocytopenia).

You may be interested in: Leukemia treatment: present and future

What is there to remember about this disease?

Hairy cell leukemia is a very atypical type of cancer, as it does not have to require immediate treatment nor does it present an obvious risk of metastasis. Many patients can live for several years without treatment And, once it is approached clinically, its life can be extended considerably.

No cancer is the end of the road until metastasis arrives, but in this case, even less. There are many treatments available, and medical research portends an increasingly promising future for patients.