chronic myeloid leukemia | Chronic myeloid leukemia

Chronic myeloid leukemia
  

Several types of chronic leukemia are distinguished: chronic myeloid leukemia (CML), Chronic myelomonocytic leukemia (CSA) and chronic lymphoid leukemia (LLC). They are the second group of Leukemias after those called "acute".

Characteristics of chronic myeloid leukemia
Chronic myeloid leukemia (CML) is a form of leukemia that develops from myeloid stem cells (usually responsible for producing blood cells). These cells have become abnormal and will gradually turn into cancerous leukemic cells.

Its main features are as follows:

It almost never affects children and, even in adults (usually between 30 and 50 years old), it is a relatively rare form of leukemia.
It involves about 600 cases each year in France, according to statistics.
As opposed to acute leukemias, this is another form of blood cancer: chronic leukemia, which is slowly evolving. However, as with acute myeloid leukemia, the myeloid cells responsible for producing red blood cells, granulocytes, monocytes and platelets are affected.
Without treatment, chronic myeloid leukemia has a very dark prognosis, as it can lead to death in a few years.

Benzene and ionizing radiation, major risk factors
According to Inserm in 2008, the two main risk factors for chronic myeloid leukemia are exposures:

benzene;
To ionizing radiation, including following radiation therapy.
Similarly, exposure to formaldehyde (this is the case for chemical industry workers and embalmers) could increase the risk of developing CML.

In 95% of cases, this blood cancer develops in persons carrying the Philadelphia chromosome, a chromosomal anomaly (discovered in Philadelphia) in which fragments are exchanged between chromosomes 9 and 22. It is important to note that this genetic anomaly is acquired during life (it is therefore not hereditary) and is only observed within leukemic cells.

Chronic myeloid leukemia is the first cancer for which a genetic anomaly has been found.

Note: Chronic myeloid leukemia associated with the production, transport, logistics and use of products containing butadiene is part of the list of occupational diseases ("Official Gazette" of 7 May 2017).

Symptoms of chronic myeloid leukemia
Chronic myeloid leukemia is a type of leukemia that evolves for several years with few symptoms. This first stage is called the chronic phase. Then, without treatment, the disease will move to the acceleration phase, in order to reach, in the most extreme cases, the blast crisis phase.

Chronic Phase
In the early days of chronic myeloid leukemia:

The blood still contains quite a few abnormal white blood cells.
The bone marrow contains only 10% of blasts (immature cells).
The rate of myeloid cells and blood platelets is still normal, which is why there are no characteristic symptoms of leukemia.
It is only when the pathology has progressed sufficiently to reach the spleen (organ which, like the bone marrow, is responsible for producing blood cells) that a first clinical sign can be found: the splenomegaly (Increase of the volume of the spleen). This is due to the fact that the spleen will seek to produce more blood cells.

However, even at this stage of the chronic phase, the symptoms are almost absent. At most, we can see increased fatigue and some form of depression.

Note: In 40% of cases, the discovery of the disease occurs fortuitously.

Acceleration Phase

After a long period of evolution of several years, the CMA will accelerate. In the absence of treatment, this acceleration phase (or acute phase) is spread over a period of a few months to one year. The formation of white blood cells is going to be important enough that the blasts (immature cells) are present in very high numbers, preventing the normal production of red blood cells and platelets. Logically, this translates into the classical symptoms of leukemia:

Anemia

Coagulation disorders (Hematomas following the slightest shock);

Infections sometimes accompanied by fever and night sweats;

Splenomegaly (Increase in spleen volume);

Loss of appetite and weight

Asthenia (high fatigue) with reduced capacities.

Good to know: Some chronic myeloid leukemias pass directly from the chronic phase to the blast crisis, without acceleration phase.

Blast crisis

When one arrives at the blast crisis stage, the vital prognosis is committed in the short term. At this level, leukemic cells are more numerous than normal cells and are disseminated in the bloodstream. The body is therefore experiencing the greatest difficulty in producing white blood cells and blood platelets that are capable of fulfilling their mission properly.

The symptoms can no longer be ignored. These are the same as those observed in the acceleration phase, but more significantly:

Anemia strongly affects the physical capacity of patients;

The risk of infection is very important;

Clotting disorders are major.

Note: At this stage, it is virtually impossible to effectively control the CMA; At the most it is possible to alleviate a little the symptoms of the patient.