Leukemia

Overview: What is leukemia ?

Literally translated, leukemia means “white blood” – affected individuals usually have too many white blood cells in their blood. Generally, leukemia refers to various diseases in which blood formation in the bone marrow is disturbed. Due to the malfunction of certain control genes, incompletely developed white blood cells are released into the blood. These are non-functional, but usually multiply very quickly and uncontrolled. As a result, they disrupt normal blood formation in the bone marrow, producing too few red blood cells, healthy white blood cells and platelets. The immature white blood cells spread throughout the body and can settle in organs such as the spleen, liver, tonsils, lymph nodes and other body tissues.

The function of the blood components

Red blood cells (erythrocytes): They make up 99 percent of blood cells and transport oxygen from the lungs to the various tissues of the body.

White blood cells (leukocytes): These cells fight off pathogens and eliminate defective or overaged endogenous cells. They are an essential component of the immune system. Thus, B and T lymphocytes, as well as granulocytes, belong to the white blood cells.

Blood platelets (thrombocytes): They ensure that bleeding is stopped in the event of an injury. As soon as a vessel is injured, platelets accumulate there and contribute to the closure of the vascular wound. At the same time, they release substances that promote blood clotting.

Four types of leukemia (blood cancer)

Experts essentially distinguish between four different types of leukemia (blood cancer), each of which requires different treatment:

• Acute lymphoblastic leukemia (ALL)
• Chronic Lymphocytic Leukemia (CLL)
• Acute myeloid leukemia (AML)
• Chronic myeloid leukemia (CML)

Leukemias arise from blood stem and progenitor cells. In the acute forms, the disease usually appears suddenly and with symptoms such as weakness, bleeding and a tendency to infection. The chronic forms, on the other hand, develop slowly over months or even years and begin insidiously. Acute leukemias in particular have various subtypes, each of which responds to different therapies and whose chances of cure can vary greatly.

Frequency and age

Compared to other cancers such as breast cancer, prostate cancer or colon cancer, leukemia is rather rare. It accounts for about three percent of tumor cases. In Switzerland, approximately 1,100 people are diagnosed with blood cancer every year. 580 people die of leukemia each year. Almost half of leukemia patients are over 70 years old. Children are rarely affected: Only four out of 100 people diagnosed with leukemia were under the age of 15. Acute lymphoblastic leukemia (ALL), however, occurs particularly frequently in children and is also the most common type of cancer among them. ALL is newly detected in an average of 1 in 100,000 people each year. Acute myeloid leukemia, which primarily affects older adults, is diagnosed in three to four out of every 100,000 people each year.

Leukemia: Causes and risk factors

Why degenerate leukocytes develop in some people is unclear. At one point, errors occur in the duplication of DNA in blood progenitor cells. Nevertheless, some factors can increase the risk of developing leukemia. These include:

• Chemicals
• Radiation
• Genetic factors
• Certain medications
• Tobacco use

The above factors may increase the risk, but do not mean that they must cause cancer.

Symptoms: leukemia manifests with fatigue and pallor

In chronic leukemia, there are often hardly any symptoms to be detected. Therefore, it is often only noticed after a long time or during routine examinations. In acute leukemia, on the other hand, symptoms usually appear suddenly. They can vary greatly depending on how the disease changes the total number of blood cells. Sometimes sufferers suffer from single of the following symptoms, sometimes from several:

• Fatigue
• Paleness
• Fatigue
• Bleeding from the nose or gums
• Dizziness
• Headache
• Loss of appetite
• Fever
• Frequent infections
• Night sweats
• Enlarged lymph nodes (in lymphocytic leukemias)

In detail, the complaints depend on how the blood is composed:

• If too few mature white blood cells are produced, the immune defense functions only to a limited extent. Frequent and sometimes severe infections are the result.
• If red blood cells are missing, too little oxygen is transported in the body. That is why those affected can quickly become exhausted and fatigued, for example.
• If too few platelets are produced, hemostasis is impaired. As an example, wounds can then no longer be closed as usual and bleeding occurs.

On the other hand, people suffering from blood cancer form too many defective blood cells. Some sufferers may have abdominal pain because the liver or spleen are enlarged. If the leukemia cells affect the central nervous system, dizziness, headaches or paralysis may result. In acute leukemia, the health of affected individuals can deteriorate rapidly. Therefore, such symptoms must be clarified quickly.

Leukemia/Blood Cancer: Diagnosis with us

We already recognize the first signs of leukemia in the blood count. The concentrations of the various blood cells (erythrocytes, leukocytes and platelets) and the blood pigment hemoglobin are measured. A differential blood count provides information about which subtypes of leukocytes are present in the blood and in what concentration. In doing so, we can see under the microscope how many mature and immature leukocytes are present in the blood.

If abnormalities are detected in this blood count, we confirm the diagnosis by performing a bone marrow examination. In this procedure, we remove some bone marrow with a needle from the pelvic bone under local anesthesia and a bone marrow biopsy. Microscopic examination in the laboratory then shows the quantities of bone marrow cells present and what they look like.

Depending on the symptoms, further examinations may be necessary: If we suspect that the central nervous system is affected, we check its fluid (cerebrospinal fluid) with a cerebrospinal fluid puncture and look for leukemia cells. We use imaging techniques such as ultrasound, CT or MRI to see pathologically altered organs or lymph nodes. FDG-PET/CT can also detect increased metabolism in lymph nodes and organs.

Genetic examination

For the treatment of blood cancer it is important to characterize the diseased blood cells as precisely as possible. For this purpose, certain chromosomal regions and genes are examined which may be associated with the development of leukemia. In addition, surface proteins are determined and quantified by immunophenotyping. This information helps us find the best possible treatment.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Leukemia: prevention, early detection, prognosis

We have made significant progress in the treatment of leukemia in recent years. This has significantly improved the prognosis of certain forms of leukemia. However, according to the current state of knowledge, there are hardly any factors that can be influenced in the development of leukemia. Accordingly, we continue to work on improving the diagnosis and therapy of these altogether rare diseases.