Chronic Myeloid Leukaemia
About the Condition
Leukaemia is cancer of the white blood cells. The term chronic leukaemia is used to describe the type of cancer that progresses slowly over many years, people with chronic leukaemia often show few symptoms for many years. This means that the condition is often diagnosed coincidentally, during routine check-ups or blood tests for other issues. Chronic leukaemia is further classified according to the type of white blood cells that are affected by cancer – chronic myeloid leukaemia (CML) affects the myeloid cells, which perform a number of different functions, such as fighting bacterial infections, defending the body against parasites and preventing the spread of tissue damage
All types of leukaemia originate in the bone marrow, which produces stem cells. These cells have the ability to develop into three important types of blood cell:
- red blood cells – which carry oxygen around the body
- white blood cells – which help fight infection
- platelets – which help stop bleeding
In leukaemia, a genetic mutation in the stem cells causes a huge over-production of white blood cells and corresponding drop in red blood cells and platelets.
It’s this lack of red blood cells which causes symptoms of anaemia, such as tiredness, and the lack of platelets that increases the risk of excessive bleeding. The overproduction of white blood cells means that the myeloid cells produced are immature and unable to fulfill their function, leading to a weakening of the immune system.
Chronic myeloid leukaemia is quite a rare type of cancer. Around 8,600 people are diagnosed with leukaemia every year in the UK, and in 2011 only 680 of those were diagnosed with CML*. CML can affect people of any age, but it is more common in people aged 40-60*.
Most people with the condition have an abnormal chromosome, where a section of DNA from one chromosome has been swapped with a section from another. This is called the Philadelphia chromosome and it makes the cell produce a protein that encourages the leukaemic cells to resist normal cell death and grow and multiply far more quickly than usual.
What triggers the development of chronic leukaemia and causes the initial mutation in stem cells is unknown, although there are many suspected risk factors, including:
- Exposure to extremely high levels of radiation, such those recorded after an atomic bomb explodes, or those released after a nuclear reactor accident, such as the one at Chernobyl.
- Exposure to a chemical called benzene, which is found in petrol and is also used in the rubber industry (in the UK there are strict controls to protect people from prolonged exposure).
- Exposure to pesticides or chemicals associated with industries such as:
- Agricultural work
- Rubber or plastic manufacture
- Tailoring/ Dressmaking
There is some evidence to show an increased risk of chronic leukaemia in people who:
- are obese
- have a weakened immune system – due to HIV or AIDS or taking immunosuppressants after an organ transplant
- have inflammatory bowel disease – such as ulcerative colitis or Crohn’s disease
In its early stages, chronic myeloid leukaemia usually causes no noticeable symptoms and is often diagnosed during tests for a different condition. When symptoms do develop, they are similar to those of many other illnesses and can include:
- frequent infections
- unexplained weight loss
- a feeling of bloating
- less commonly, swollen lymph nodes – glands found in the neck and under your arms, which are usually painless
CML can also cause swelling in your spleen (an organ that helps to filter impurities from your blood). This can cause a lump to appear on the left side of your abdomen, which may be painful when touched. A swollen spleen can also put pressure on your stomach, causing a lack of appetite and indigestion.
The symptoms of CML in its advanced stage will be much more noticeable and troublesome. They include:
- severe fatigue
- bone pain
- night sweats
- easily bruised skin
If any of these symptoms apply to you, or if you have any concerns about similar symptoms, it is essential that you see your doctor at once, as your chances of recovery are much higher if your cancer is diagnosed early.
If you are referred to CCL for diagnosis, your consultant or oncologist will advise you as to which tests are relevant, however most cases of chronic myeloid leukaemia are often first detected when a routine blood test is carried out to diagnose another, unrelated, condition. Once CML is suspected, tests include:
- A blood test, to check for a high number of abnormal white blood cells in the sample
- A bone marrow biopsy, during which a haematologist will take a small sample of bone marrow to examine under a microscope. This involves inserting a needle into a large bone, usually the hip bone, to extract the marrow, and is done under local anaesthetic
- Cytogenetic testing, which involves identifying the genetic make-up of the cancerous cells. There are specific genetic variations that can occur during leukaemia, and knowing what these variations are can have an important impact on treatment.
- A polymerase chain reaction (PCR) test, which can be done on a blood sample. This is an important test to diagnose and monitor the response to treatment.
- A Computerised Tomography (CT) scan, which shows a 3D image of the area being looked at
- An X-ray, which is when low level radiation is used to create an image of the body
At CCL, patients with CML are treated by a team of different specialists, called a Multi-Disciplinary Team, or MDT, from our Haemato-Oncology department, headed by Professor Ray Powles, CBE. This team works together to create a treatment plan to suit the individual needs of the patient. Because CML is a chronic condition, the first treatment is usually medication to stop the progression of the cancer.
Imatinib tablets are usually given as soon as you have been diagnosed with chronic myeloid leukaemia, to slow its progression. These tablets are taken every day for life, and most patients do really well on them.
The aim of treatment is to achieve the following:
- by three months, correct the blood count
- by 12 months, clear the bone marrow of cells containing the Philadelphia chromosome
- by 18 months, get to a stage where the leukaemia can only be detected by a very sensitive molecular test (molecular remission)
If the leukaemia reaches an advanced stage, further treatment is considered, including:
- Chemotherapy, which involves the use of chemical agents which are toxic to cancer cells, destroying them and preventing them from spreading to different areas. This can be given by injection or in tablet form.
- A bone marrow or stem cell transplant, which is a possible alternative if chemotherapy has been unsuccessful. Before transplantation can take place, the patient will need to have intensive high-dose chemotherapy and radiotherapy to destroy the cells in their bone marrow. The donated stem cells are then given through a tube into a blood vessel, in a similar way to chemotherapy medication.
Cancer doesn’t just leave a physical impact on an individual, it can have a huge emotional effect as well. Cancer and its treatment can be overwhelming, causing a wide variety of emotions, and it is important to remember that there is no right or wrong response. Reactions vary hugely from person to person, and most people find that it becomes easier to cope when they’re given additional support, so that’s what we do.
At CCL we provide support that caters to both the physical and emotional needs of the patient, before, during and after treatment. We offer a wide range of services for patients, as well as their loved ones, designed to make a very difficult time as easy as possible, and to give our patients the best treatment and support possible.
Chronic Myeloid Leukaemia Consultants