A-Z

Leukaemia

What is leukaemia?

Leukaemia is a cancerous illness of white blood cells, which are responsible for fighting infection. Like the other sorts of blood cell in the body (red blood cells, which carry oxygen; and platelets, which help control bleeding), white blood cells form in the bone marrow, a spongy material that fills the bones.

In the bone marrow, immature cells multiply and mature into red cells, white cells and platelets. As they mature they are released into the bloodstream.

In leukaemia, the white blood cells instead of growing and developing normally grow out of control and do not mature. This uncontrolled growth of immature white blood cells can crowd the bone marrow preventing it from producing healthy white blood cells, red blood cells and platelets. 

There are several different types of leukaemia, each with its own particular characteristics and treatment. We asked an expert, Professor Asim Khwaja from University College London, to explain how the four main types differ:

•    acute myeloid leukaemia (AML),
•    acute lymphoblastic leukaemia (ALL),
•    chronic myeloid leukaemia (CML) and
•    chronic lymphocytic leukaemia (CLL)

 

Professor Khwaja explains the differences between the four main types of leukaemia.

Professor Khwaja explains the differences between the four main types of leukaemia.

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There’s two main types of leukaemia. There is acute leukaemia and chronic leukaemia. And then within the acute leukaemias there’s two types' acute myeloid leukaemia and acute lymphoid leukaemia, and the same applies to the chronic leukaemias. And the definition of acute leukaemia comes from the fact that it normally is a very rapidly growing cancer and if left untreated would result in relatively short survival of the patient, but with effective treatment that can be reversed.
 
And the symptoms that one normally gets with acute leukaemia are a consequence of the fact that the leukaemia takes over the bone marrow and therefore you can’t make your normal blood cells anymore. So the patient may become tired and breathless because they’re not making red blood cells which carry the oxygen around the body. They may notice that they’re having frequent infections because the normal white blood cells are not being produced. And also sometimes you get bruising or inappropriate bleeding because the blood cells that stop you doing that, platelets, are also reduced in number.
 
Chronic leukaemias are normally much more slow growing. And in fact before we had treatments for leukaemias people could have certain types of chronic leukaemia for many, many years without requiring any treatment or coming to any harm from it. And with these more commonly the symptoms are to do, again patients can complain of fatigue and tiredness and weight loss but it doesn’t normally affect the bone marrow function the way that the acute leukaemias do.
 
So there are, in the acute leukaemias there are two types, the myeloid type and the lymphoblastic type. And similarly in the chronic leukaemias there is a myeloid and a lymphoid type. The difference between these two is that they develop from slightly different types of white blood cells. So normally in our circulation we have white blood cells called neutrophils, which are the myeloid type of cells. These are very important in fighting bacterial infection in particular. And then the other main type of white blood cell we have is the lymphocyte, and this is important, especially important in fighting viral infections. So in chronic or acute myeloid leukaemia the cancer is developed in a cell that would normally have become a neutrophil, it would have become a normal myeloid cell but has become damaged in some way and is now growing out of control. And in the lymphoid types of leukaemias, what has happened is that a cell normally destined to become a lymphocyte has started to grow out of control and that’s what the lymphoid leukaemias are.
On this section of healthtalk.org about leukaemia you will find the stories of people who have one of the four main types of leukaemia described above. Other, rarer types are represented too, such as hairy cell leukaemia, so called because of the hair-like projections that can be seen through a microscope on the surface of the affected white blood cells. Several other non-cancerous conditions affect the production of blood cells, and may later develop into leukaemia; we have included the stories of some people with a condition called myelodysplastic syndrome. Professor Khwaja explains what this is.
 

Professor Khwaja explains myelodysplastic syndrome and how it is related to leukaemia.

Professor Khwaja explains myelodysplastic syndrome and how it is related to leukaemia.

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So myelodysplasia or myelodysplastic syndrome, MDS, this a group of related conditions where you have poor production of your normal blood cells, but in contrast to acute leukaemia there isn’t an excess of malignant cells. So instead of the blood cells developing normally in the bone marrow, they develop in an abnormal way and they tend to die prematurely in the bone marrow and don’t find their way into the blood. So typically what this means is the patient usually is anaemic and needs regular red blood cells transfused to them. And sometimes there can be a reduction in the other blood cells as well, the platelets and the white blood cells. So the treatment in most instances requires regular transfusions and chemotherapy type treatments are not commonly used.
 
Now, as I said at the beginning, it’s a range of conditions some of which behave in a very indolent and slow way in that, although the patient requires regular transfusions, the disease doesn’t progress in any sinister way. In other individuals the myelodysplastic syndrome can convert to an acute myeloid leukaemia, and at that stage it would require treatment with chemotherapy. At the point at which the MDS is diagnosed there are certain tests including the chromosomal make-up of the bone marrow cells that will help the clinicians to decide whether it’s the type of MDS that is less likely or more likely to develop into leukaemia.
The treatment for leukaemia varies according to what type it is. In the following clips, Professor Khwaja outlines how each of the main types of leukaemia is treated. For more details about specific treatments see: 'Chemotherapy', 'Stem cell or bone marrow transplants', 'Biological therapies', 'Radiotherapy' and 'Supportive treatments'.
 

Professor Khwaja explains that treatment for acute leukaemias needs to be started promptly and...

Professor Khwaja explains that treatment for acute leukaemias needs to be started promptly and...

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So with acute leukaemias the growth of the cancer cells is very rapid and therefore we need to get treatment started urgently, normally in a matter of days. And the treatment consists of chemotherapy. So these are drugs that damage the leukaemia cells and we hope cause them to die. Because the leukaemia cells can travel throughout the body and are found throughout the bone marrow the treatment has to be in a form that travels throughout the body, so you can’t have an operation. We need to give chemotherapy drugs that travel throughout the blood stream. And these are normally given in short intensive bursts of treatment, so this is sometimes called ‘intensive chemotherapy’. So there are combinations of drugs. You normally get at least two, sometimes three, and these are given daily over of a period of about a week to ten days.
 
This sort of treatment needs to be given in hospital because one of the consequences of the chemotherapy is that there is damage to normal blood cells and normal bone marrow cells, and temporarily the patient has very low levels of these cells. So we have to support them through that period. They’re very likely to need blood transfusions, platelet transfusions and also treatment for infection. So this is a period when because of low immunity and the patient is very susceptible to getting serious infections and has to spend time in hospital.
 
What we’re hoping with this intensive course of treatment is to induce what is called a remission, which means that we can’t detect the leukaemia cells anymore. However, we know that if we were to stop treatment at that stage the leukaemia would inevitably come back because although we can’t detect them there are still some left behind. So once the first course of treatment is completed, which normally for acute leukaemias takes about a month to six weeks, you usually have a short break of a week to two weeks, and then have further courses of treatment. And for acute myeloid leukaemia that normally takes about four courses of intensive chemotherapy which, with the intervals in between, requires about a six month period to complete your treatment. And normally that’s when the treatment stops, all being well. And then after that there’s monitoring usually as an outpatient to make sure that things stay in remission.
 
For acute lymphoblastic leukaemia the treatment is very similar in the initial phases with intensive chemotherapy but then, once that’s been completed and you’re an outpatient again there is a more protracted period of about eighteen months after that where you have low doses of outpatient type chemotherapy. So these are doses not sufficient to reduce your normal blood cells right down, so you don’t need to be in hospital for them, but they’re a very effective and a very important part of the treatment.
 

Professor Khwaja explains that treatment for chronic myeloid leukaemia nowadays involves daily...

Professor Khwaja explains that treatment for chronic myeloid leukaemia nowadays involves daily...

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So for chronic myeloid leukaemia the treatment now involves most commonly taking a new type of drug which has become available over the last few years, and this is a drug called imatinib or Glivec. And this is a new type of drug in that it specifically is targeted towards a genetic abnormality that’s found only in the CML cells. So the CML cells are growing out of control because they’ve got a hyperactive molecule in them and what the Glivec does is it binds to this particular molecule and stops it working normally, and that puts the patient back into remission and restores normality in their blood. With the Glivec we at the moment don’t know how long we need to keep treatment going for and it’s likely that it would need to be life long. It’s a relatively simple treatment to take. It’s in the form of a tablet which needs to be taken daily over, as I say, probably many years.
 
You were talking about the chromosomal abnormality in CML. Is that the Philadelphia chromosome?
 
That’s right.
 
Is that unique to CML?
 
It’s not completely unique to CML. It’s also found in certain types of ALL, acute lymphoblastic leukaemia, but everybody who has CML has that abnormality in their leukaemia cells only. Not in other cells in the body but purely in the leukaemia cells. So the Glivec, the imatinib is also being used for treatment of those types of ALL where the Philadelphia chromosome may be present. But for those conditions it needs to be combined with intensive chemotherapy to get a remission, whereas in CML the Glivec alone is sufficient usually to induce the remission.
 

Professor Khwaja explains that for most chronic lymphocytic leukaemias a watch and wait policy is...

Professor Khwaja explains that for most chronic lymphocytic leukaemias a watch and wait policy is...

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So with chronic lymphocytic leukaemia the patient’s condition can vary hugely in that this can be present as a very, very slow growing and relatively benign condition, and sometimes it can be more aggressive than that. And in many cases no treatment is required initially so that one can just watch and wait until treatment becomes necessary. In some people this may never happen or it may take many years to happen. And there’s no advantage in starting the treatment early, and that can introduce complications of the treatment without actually offering any extra benefit.
 
The sorts of treatment that you need for CLL are again chemotherapy type drugs but these are of a relatively low intensity type so that they can be delivered as an outpatient. You don’t normally need to be admitted to hospital for them. And there are some newer treatments coming through which are being incorporated also with monoclonal antibodies that, again, are more specifically targeted to the CLL cells.
 
So what determines when someone with CLL needs treatment?
 
There may be a number of things. It depends if the patient has significant symptoms. Sometimes with CLL this can also make the lymph glands in the body enlarge because the CLL cells can track their way into the lymph glands. So sometimes there are symptoms from having very large lymph glands that people can find uncomfortable or painful. CLL can affect the normal bone marrow function if the level of the leukaemia rises, so that the patient may become anaemic or start to get a lower platelet count than normal. And that would be another reason to start treatment, to reverse that balance, to try and restore some normality to the bone marrow. Also sometimes the CLL can get to a stage where the patient may be losing weight or has fevers or is generally becoming more poorly, and again that would be a reason to start treatment.

Before their own diagnosis most people we spoke to had known little or nothing about leukaemia and how it can affect people. However, all had heard of it and had known it was serious, often because they had known someone else who'd had it. Many people had associated it with children and hadn’t realised that adults could also develop it. Several knew it was a disease of the blood or the bone marrow, but few knew that there were different types of leukaemia. Some people said that leukaemia had just been a scary word to them before their diagnosis and a few hadn’t understood that it was a form of cancer until they were specifically told this or when chemotherapy was mentioned.

 

Before his leukaemia diagnosis Ian said he knew very little about it, just that it was a serious...

Before his leukaemia diagnosis Ian said he knew very little about it, just that it was a serious...

Age at interview: 43
Sex: Male
Age at diagnosis: 35
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Did you know anything about leukaemia before all this happened to you?
 
Not a lot. Not a lot. I knew it was something that maybe children, it was something a lot of children would have. And it was a cancer type illness. Probably related to the blood, but that’s about, very scant details really, yeah. It was quite a big word, I know that much, it was quite a big word. I knew it was not something that you you’d want to be told about.
Last reviewed: December 2018.
Last updated: December 2018.


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