In Germany, one person receives the devastating diagnosis of blood cancer every 15 minutes. Many patients are children and adolescents, but older people are also frequently affected. This form of cancer is rather rare compared to other cancers. But what exactly is blood cancer? How well can blood cancer be diagnosed and what treatment options are available?

What is blood cancer (leukemia)?

Many people colloquially refer to leukemias as blood cancers. Strictly speaking, however, leukemias are diseases of the blood-forming system. This means that not only the blood is affected, but mainly the bone marrow or the lymphatic organs. The consequence of leukemia is disturbed blood formation due to the uncontrolled multiplication of malignant blood cells. As a result of these cancer cells, the blood can no longer perform its vital tasks, such as fighting infections, transporting oxygen, or stopping bleeding. Also, these altered leukemia cells can spread throughout the body via the blood and, for example, also affect and damage the nervous system and internal organs.

What are the different forms of leukemia?

Doctors and researchers divide leukemia diseases into leukemic cells based on their gene alteration and into lymphocytic and myeloid leukemias based on the type of cells affected. These special designations are used only to distinguish the affected cell line of origin. Besides, there is a further classification according to the course of the disease. There is an additional distinction between acute and chronic leukemias:

Myeloid leukemias: originate from the precursor cells of granulocytes (are responsible for our “innate” immune defenses), and by extension, erythrocytes (our red blood cells) and platelets (essential for intact blood clotting).

Lymphocytic leukemias: affect lymphocytes (are responsible for our “acquired” immune defenses) and their precursor cells.

Acute leukemia: occurs suddenly with severe disease symptoms and are life-threatening diseases that lead to death in a few weeks to months if left untreated.

Chronic leukemia: it can take months or years for the affected person to suffer from the first symptoms.

All of these four forms can present in combinations with different symptoms and courses:

Acute myeloid leukemia (AML): most common acute leukemia, starts quite suddenly and progresses rapidly and about half of the patients are older than 70 years.

Chronic myeloid leukemia (CML): has a slow, insidious course (with exceptions), the median age of onset is 50 to 60 years, and occurs very rarely in children.

Acute lymphoblastic leukemia (ALL): most common of all forms of leukemia, starts quite suddenly and progresses rapidly and occurs mainly in children (ALL is the most common type of cancer in children) and otherwise in adult patients usually older than 80 years.

Chronic lymphocytic leukemia (CLL): most common leukemia in adults with slow and insidious progression, the median age of onset is 70 to 75 years old

and does not belong to the “true” leukemias, but lymphatic cancers (malignant lymphomas).

What are the causes of the different leukemia diseases?

The causes of the various forms of blood cancer have not yet been identified. However, experts have identified several risk factors that favor the development of leukemia. These include genetic predisposition, age, smoking, radioactive or X-ray radiation, chemical substances such as benzene or insecticides, or even very rare viruses.

How can leukemia be diagnosed?

Symptoms such as reduced performance, pallor, palpitations, frequent nosebleeds, or persistent fever are often unspecific and often occur in many other and sometimes harmless diseases. Therefore, they are not always taken seriously right away. However, with such complaints, there is always a suspicion of leukemia. In many cases, it is possible to make a detailed diagnosis with the help of immunophenotyping alone, while in other cases an additional examination of the bone marrow or molecular pathological examinations are necessary. Immunophenotyping is performed by flow cytometry, which allows rapid diagnosis. In this examination, leukocytes are stained and sorted using immunological markers. Differentiated and accurate differentiation of individual leukocytes by function and stage of maturation is achieved. Due to its high sensitivity, flow cytometry is becoming increasingly important in staging (assessment of tumor extent) examinations of the blood and bone marrow and can thus help to design therapy options that are appropriate for the patient.

What are the treatment options for leukemia?

Leukemia treatment is individually adapted to each patient. Various factors play a role in this. In addition to the patient’s age and general state of health, the course of the disease (acute or chronic) is particularly important. The therapy then ranges accordingly from chemotherapy to immunotherapy to stem cell transplantation. Depending on the cells affected, the therapy is tailored to the patient, which is why immunophenotyping is highly relevant. Also, possible side effects such as increased susceptibility to infections, nausea, and pain are treated appropriately with special drugs. Patients are also examined regularly during and after therapy. If there is a relapse, the cancer cells can be detected early in this way using flow cytometry. Besides, follow-up care is concerned with treating any long-term consequences of the previous therapy.