Understanding Chronic Myeloid Leukemia
Chronic myeloid leukemia (CML), or chronic myelogenous leukemia, is a slow-growing form of cancer that affects the bone marrow and blood. Like acute myeloid leukemia, CML originates in the myeloid cells. When functioning properly, myeloid cells produce mature red blood cells, platelets and non-lymphocytic white blood cells. When healthy myeloid cells undergo cancerous changes and transform into leukemia cells, they are no longer regulated by normal growth patterns. Instead, they can rapidly produce abnormal copies of themselves, which can leave the bone marrow, enter the bloodstream and spread to other organs.
Compared to acute leukemias, this process occurs much more slowly in chronic myeloid leukemia. Unlike other types of leukemia, however, CML can transform into a more rapidly spreading, acute cancer over time. As a result, prompt detection and comprehensive treatment are extremely important.
What are the symptoms of chronic myeloid leukemia?
Chronic myeloid leukemia often doesn’t produce noticeable symptoms in its early stages. In fact, many patients don’t realize there is a problem until they have routine bloodwork performed. When symptoms do occur, they may include:
- A feeling of pain deep within the bones
- Fatigue and weakness
- Night sweats
- Easy bleeding
- Pale skin
- Feeling sick after eating
- Unexplained weight loss
- Tenderness or a sense of fullness in the belly
- An enlarged spleen, which may cause discomfort below the left ribcage
These symptoms aren’t exclusive to chronic myeloid leukemia, however. Many common benign conditions and other cancers can cause these symptoms as well. If you notice any persistent symptoms that concern you, be sure to schedule an appointment with your physician.
What causes chronic myeloid leukemia?
The specific factors that trigger the transformation of healthy myeloid cells into leukemia cells are not yet fully understood. However, we do know that this cancer develops as a result of abnormally dividing cells in the bone marrow.
About 90 percent of people with chronic myeloid leukemia have a “Philadelphia chromosome.” A normal cell has 23 pairs of chromosomes, which house the DNA that controls cell function. The Philadelphia chromosome occurs when two chromosomes swap uneven sections with each other, creating an extra short chromosome. This shortened chromosome can produce a gene (BCR-ABL) that promotes the overproduction of tyrosine kinase, a protein that allows for the rapid growth of diseased blood cells in the bone marrow. Eventually, these abnormal blood cells can crowd out healthy cells.
Are there risk factors for chronic myeloid leukemia?
A risk factor is a characteristic that may leave an individual at an increased likelihood of being diagnosed with a certain illness. Established risk factors for chronic myeloid leukemia include:
- Age – The risk of chronic myeloid leukemia increases over time.
- Gender – Chronic myeloid leukemia occurs more commonly in males than females.
- Radiation exposure – Being exposed to radiation, whether through previous cancer treatment or environmental contact, may increase the chance of developing chronic myeloid leukemia.
Unlike that of many other cancers, the risk of chronic myeloid leukemia does not appear to be impacted by genetics, chemical exposures or unhealthy lifestyle habits like smoking and poor diet.
It’s important to note that chronic myeloid leukemia is an uncommon disease. Having these risk factors does not necessarily mean you will develop this condition. On the other hand, some people are diagnosed with chronic myeloid leukemia without having any known risk factors.
How is chronic myeloid leukemia treated?
Chronic myeloid leukemia is treated according to its phase (chronic, accelerated or blast) as well as the patient’s age, overall health and other individual factors. Here’s a brief overview of the treatment options that may be used in each phase:
The typical treatment approach for patients with chronic-phase disease – or the earliest and most treatable phase – is targeted drug therapies that block the function of the tyrosine kinase protein. Less commonly, stem cell transplantation may be performed.
During the accelerated phase, cancer cells begin to build up in the body and cause symptoms. Patients with accelerated-phase chronic myeloid leukemia may receive higher dosages of targeted drug therapies, as well as chemotherapy and stem cell transplantation if an appropriate donor is found.
Finding viable treatment options becomes more challenging in the blast phase, when the leukemia cells are the most aggressive and abnormal. Some patients may achieve short-term remission with high doses of targeted drug therapy and chemotherapy. Allogeneic stem cell transplantation is the only known curative treatment for blast-phase chronic myeloid leukemia, but it is often unsuccessful. There are currently several research initiatives and clinical trials focused on improving treatment options and outcomes for patients with late-stage leukemias.
Moffitt’s approach to addressing chronic myeloid leukemia
At Moffitt Cancer Center, we offer a complete range of diagnostic tools and treatment techniques for chronic myeloid leukemia. In a single, convenient location, we provide:
- Diagnostic bloodwork
- Diagnostic imaging
- Targeted therapy
- Radiation therapy
- Stem cell transplantation
- Supportive care options
These options and others are available through our Malignant Hematology Program, which focuses exclusively on the treatment of blood and bone marrow cancers. The oncologists in this program are among the nation’s foremost experts on leukemia and lymphoma treatment, and are wholly committed to tailoring their treatment recommendations to account for each patient’s unique needs. This team is also actively involved in our groundbreaking research, including clinical trials that test the effectiveness of new leukemia treatments. As a National Cancer Institute-designated Comprehensive Cancer Center, we are one of the country’s top destinations for hematological oncology research and clinical trials.