Understanding Chronic Myelogenous Leukemia

Many people have asked me what CML is, so I will try to begin to define this type of blood cancer to the best of my understanding and ability. It may take a few posts, but hang in there as this is all new to me, too.

First of all, Leukemia is a cancer of the marrow and blood. There are four major types of leukemia; acute myelogenous leukemia, chronic myelogenous leukemia, acute lymphocytic leukemia and chronic lymphocytic leukemia. The type of leukemia is called lymphocytic or lymphoblastic if the cancerous change takes place in a type of marrow cell that forms lymphocytes. It is called myelogenous or myeloid if the change takes place in a type of marrow cell that would normally go on to form red cells, some white cells and platelets.

Acute leukemia affects mostly the cells that are either unformed or not yet fully developed and progresses rapidly. The immature cells are unable to carry out their normal functions.  Chronic leukemia, the type that I have, allows for a greater number of these cells to develop and develops slowly over time. The more mature cells are able to carry out some of their normal functions which allow a person to carry on with their everyday life without being aware that they have cancer. Often CML is diagnosed with routine blood work, included as part of a yearly physical. Sometimes the disease progresses so far without being detected that a person will eventually develop signs and symptoms of leukemia. My diagnosis was a little bit of both. I had symptoms, none of them preventing me from carrying on with my ever day life, and I also had a scheduled check-up that I mentioned my symptoms during; that prompted my doctor to do a routine blood count.

CML has several other names; chronic myeloid leukemia, chronic granulocytic leukemia and chronic myelocytic leukemia. This type of cancer results from the change or mutation to the DNA of a single marrow cell. The mutation is not present at birth and there does not seem to be a specific reason as to why the mutation occurs. Some places I have researched have suggested that high exposure to radiation could be a factor, but I am finding no real evidence or proof confirming such. My guess is that they really just don’t know, or they do not want us to know!

It seems as though the CML cells are tenacious little buggers; they have the ability to grow and survive better than the existing healthy cells. They move in and set up shop, crowding out the normal cells. As time goes on, they continue to multiply and your normal cells become fewer and fewer with the abnormal cells becoming greater and greater. Because a CML patient still has some normal cells, the chronic phase of the disease is usually less severe than acute leukemia. The normal amount of white blood cells is between 4,000 and 10,000; when was diagnosed, I had 382,000 white blood cells. Of course they were not all mature healthy cells; they were immature useless cells that were crowding out my good cells; red and white and platelets included.

CML is not hereditary and not contagious, so I can't give it to you and my children do not need to worry! There are three phases of the disease; the chronic phase, the accelerated phase and blast crisis. There is contradictory evidence as to which phase I was in when diagnosed. At first they said that I was in blast crisis and then they said I was in the chronic phase. My current doctor is trying to acquire my original bone marrow slides in order to confirm my initial diagnosis. When reading my lab reports, in one section it states that I had 51% blasts; in another section it states that I had 2% blasts. That is a huge discrepancy, one that my current doctor hopefully solves.

So, to recap; Chronic Myelogenous Leukemia is a blood and marrow cancer that causes a mutated cell to multiply into many, many CML cells. The mutated cell is called the Philadelphia Chromosome.  That I will explain is a separate post!