Blood cancer: Leukaemia

Types of leukaemias

There are three main types of blood cancers – leukaemias, lymphomas and myeloma.

Leukaemias are cancers of white blood cells. There are two main groups of leukaemias (1):

• acute leukaemias
• chronic leukaemias.

Medically, the difference between these two types of leukaemia is in how well-developed the affected white blood cells are (1). Doctors call this ‘differentiation’. There are different types of acute and chronic leukaemias. It is important to find out from your doctor which type of leukaemia you have. Your doctor will choose the best treatment for you depending on the type.

For patients, the main difference between acute and chronic leukaemia is in how the disease develops.

Remission and cure

In cancer care, doctors tend to talk about ‘remission’ instead of ‘cure’. This is because cancers can come back sometime after treatment. If there is no sign of your disease after treatment, your doctor will call this ‘remission’. The longer you are in remission, the less likely the cancer is to come back. The risks of a cancer or leukaemia coming back vary a great deal, depending on the type you have; ask your doctor for more information.

Acute leukaemia

The affected cells are very undeveloped so very abnormal (1). They cannot carry out the work that white blood cells normally do in the body: fighting infection. The cells also multiply too quickly so there are far too many of them (3). They crowd out the normal blood cells, both red blood cells and other types of white blood cells (2).

Acute leukaemias tend to develop quickly and need treating straight away (4). If you do not have treatment, they will get worse very fast, often within weeks (2,4).

Types of acute leukaemia

There are two main types of acute leukaemia:

• acute lymphoblastic leukaemia (ALL) and
• acute myeloid leukaemia (AML).

These are named after the type of white blood cell that is affected in each condition(10).

Acute lymphoblastic leukaemia (ALL)

In acute lymphoblastic leukaemia (ALL) white blood cells called lymphocytes become cancerous (11); we do not know exactly what causes it. Risk factors include:

• smoking
• radiation
• some genetic conditions such as Down’s syndrome, and
• viral infections (12).

Symptoms

If you have ALL you may (13):

• have swollen glands (lymph nodes)
• develop bruises, nosebleeds or a rash of tiny red spots caused by bleeding under the skin
• look very pale
• have frequent fevers or infections
• feel unusually tired, dizzy or breathless
• have bone or joint pain
• lose your appetite or feel full because of a swollen liver or spleen.

Treatment

The main treatment for ALL is chemotherapy (14).

Some types of ALL have a specific change in a gene or a particular marker on the leukaemia cells. In these cases, you will also have a drug that targets that gene change or marker: a ‘biological’ or targeted treatment (15).

In ALL, leukaemia cells can get into the fluid that surrounds the brain and spinal cord (15). To prevent this, you will have chemotherapy injections into your spine (14).

If your treatment gets rid of the leukaemia completely (‘remission’) you will have ‘maintenance’ chemotherapy tablets to take for two or three years (14,16). This is to stop the leukaemia from coming back (14).

If tests show signs of leukaemia after your chemotherapy, your doctor may suggest a stem cell transplant using cells from a donor: an allogeneic transplant (14). They may also suggest a stem cell transplant if you’re in remission, but they think it will give you a better chance of stopping the leukaemia from coming back (14,16). If possible, you will receive stem cells from a relative whose bone marrow closely matches your own (14,16). If no relative is available, you may have a transplant from a matched donor who is not related to you (14).

There is a particular type of ALL called B-cell ALL. CAR-T cell therapy is another treatment option for children and young people whose B-cell ALL has come back after treatment (17).

Outlook (prognosis)

The outlook for ALL depends on a number of different factors, so it is best to ask your own specialist as they have all the information on your case and treatment.

Overall, around seven out of 10 people diagnosed with ALL survive for five years or more. The likely outcome varies a great deal with age. In children younger than 15, around nine out of 10 (90%) survive for five years or more (18).

These figures do not mean people only live for five years. Some of these people will have been cured, but doctors do not talk about being cured very often in cancer care because of the risk of the disease coming back. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five-year survival’ is a commonly quoted statistic.

Acute myeloid leukaemia (AML)

In acute myeloid leukaemia (AML), white blood cells called granulocytes become cancerous (19). As with ALL, we do not know what causes it. Being exposed to radiation, a chemical called benzene or some chemotherapy drugs can all increase risk of AML (20).

Symptoms

If you have AML, you may (20):

• look very pale
• develop bruises, nosebleeds, bleeding gums or a rash of tiny red spots caused by bleeding under the skin
• feel very tired and breathless or dizzy
• have frequent infections or fevers
• have pains in your bones
• lose your appetite or feel full because of a swollen liver or spleen (21,22).

Treatment

AML treatment depends on the type you have. The main treatment is chemotherapy. If your doctor thinks there is a considerable risk of your leukaemia coming back, they may suggest you have a donor stem cell transplant, an allogeneic transplant, after your chemotherapy (23).

One particular type of AML, called APML is treated slightly differently. Instead of chemotherapy, you have a drug made from vitamin A called tretinoin, along with arsenic (23). Although arsenic is a poison, it is used as a medicine in very small doses.

If your AML or APML comes back after chemotherapy your doctor may suggest more chemotherapy or a stem cell transplant.

Outlook (prognosis)

The outlook for AML depends on a number of different factors. So it is best to ask your own specialist as they have all the information on your case and treatment.

Around 20 out of 100 people diagnosed survive their AML for five years or more. The likely outcome varies a great deal with age. In children younger than 15, around 65% survive for five years or more (24).

These figures do not mean people only live for five years. Some of these people will have been cured, but doctors do not talk about being cured very often in cancer care because of the risk of the disease coming back. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five-year survival’ is a commonly quoted statistic.

Chronic leukaemia

The affected cells are more developed, but they are still not the same as normal white blood cells. They cannot fight infection as well as normal white blood cells, but still work to some extent. The cells multiply too quickly, but not as quickly as in acute leukaemia (4).

Chronic leukaemias develop more slowly, over months or even years (4-6). They will eventually get worse without treatment, but at a slower pace. At first, they may not cause any symptoms (7). Depending on the type you have, it may be best to keep treatment in reserve until you do have symptoms (8). But with some types, you will have treatment as soon as you are diagnosed (8).

Types of chronic leukaemia

There are three main types of chronic leukaemia:

• chronic lymphoblastic leukaemia (CLL)
• chronic myeloid leukaemia (CML)
• hairy cell leukaemia.

These are named after the type of white blood cell that is affected (10).

Chronic lymphoblastic leukaemia (CLL)

In chronic lymphocytic leukaemia (CLL), white blood cells called B lymphocytes become cancerous and are found in the blood. There is a related type of cancer, when cancerous B lymphocytes are found in the glands (lymph nodes). This is called small lymphocytic leukaemia (25).

We do not know what causes CLL or small lymphocytic leukaemia (26). It is most often diagnosed in older people. The risk of getting it is higher in close relatives of people with CLL, (27) but it is a rare disease so it is still a low risk (28).

Symptoms

If you have CLL, you may (29):

• have frequent fevers or infections
• have swollen glands (lymph nodes)
• feel full or uncomfortable because of a swollen liver or spleen
• develop bruises, nosebleeds or a rash of tiny red spots caused by bleeding under the skin
• feel very tired
• look very pale.

Treatment

If your CLL is not causing any troublesome symptoms, your doctor may just monitor your health and keep treatment in reserve - 'watch and wait'. When you do have symptoms, the choice of treatment will depend on the results of tests on your leukaemia cells. You may have a combination of chemotherapy and immunotherapy (30).

Some types of CLL have a particular gene change, or mutation, in the leukaemia cells. If your leukaemia cells have this, you will have a drug that targets it - a ‘biological’ or targeted treatment - either alongside or instead of chemotherapy. If this treatment gets rid of the leukaemia completely - remission - and you are well enough, your doctor may also suggest a donor stem cell transplant: an allogeneic transplant (30). If possible, you have stem cells from a relative whose bone marrow closely matches yours. If no relative is available, you may have a transplant from a matched donor who is not related to you (31).

If your leukaemia comes back after treatment, you may have the same treatment you had the first time around. Alternatively, you may have a drug that targets the gene change, the mutation, in the leukaemia cells - a biological or targeted therapy. If you are well enough, your doctor may suggest an SCT (32).

Outlook (prognosis)

The outlook for CLL depends on a number of different factors (32); so it is best to ask your own specialist as they have all the information on your case and treatment. Generally, CLL develops slowly and treatment can keep it under control for many years. Overall, around seven out of 10 people diagnosed (70%) live for five years or more. Younger people tend to do slightly better. Of those younger than 65, around eight out of every 10 diagnosed (80%) live for five years or more (33).

These figures do not mean people only live for five years. They relate to the number of people who are still alive five years after their diagnosis. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five-year survival’ is a commonly quoted statistic.

Chronic myeloid leukaemia (CML)

In chronic myeloid leukaemia (CML), too many white blood cells called myeloid cells develop. This happens because of a change (mutation) in a chromosome, causing it to make too much of a protein that encourages these leukaemia cells to grow. Doctors call this the ‘Philadelphia chromosome’ (34,35). You do not inherit this – it happens after you have been born (35).

We do not know why some people develop the Philadelphia chromosome and get CML (36). Your risk can be increased if you have been exposed to radiation or a chemical called benzene (36,37). But in most patients in the UK, these are unlikely to be the cause (37,38). CML becomes more common with age, with the highest incidence in people in their 80s (39).

Symptoms

If you have CML, you may (40):

• have lost weight without trying
• have temperatures and sweating at night
• feel full or uncomfortable because of a swollen liver or spleen
• feel very tired
• look pale
• have nosebleeds or bruise easily (40,41)
• have aches and pains in muscles and joints (40,41).

Treatment

When first diagnosed with CML, you are most likely to be treated with a drug that targets the protein made by the Philadelphia chromosome in the CML cells. There are several of these drugs, called tyrosine kinase inhibitors (TKIs) (42). After treatment, there may be no clinical signs of CML (remission) and your doctor will monitor you with blood tests (43).

If a TKI does not help, or your CML comes back, your doctor may suggest trying a different TKI or a stem cell transplant using cells from a donor - an allogeneic transplant. You may have a stem cell transplant as a first treatment if your CML is already advanced when it is diagnosed (42).

Outlook (prognosis)

The outlook for CML is generally very good with TKI treatment. CML often develops very slowly and treatment can often control it for many years. Around seven out of 10 people diagnosed (70%) live for five years or more. The outlook is generally better for younger people. Of those under 65, around nine out of 10 (90%) live for five years or more (43).

These figures do not mean people only live for five years. They relate to the number of people who are still alive five years after their diagnosis. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five-year survival’ is a commonly quoted statistic.

Hairy cell leukaemia (HCL)

In hairy cell leukaemia (HCL), your body makes too many white blood cells called B lymphocytes. These cells have hair-like projections sticking out of them, which is where the name comes from. It is a rare and slow-growing type of chronic leukaemia (44).

We do not know what causes HCL (45). It is nearly always diagnosed in people over 30. It is also five times more common in men than in women (46).

Symptoms

If you have HCL, you may:

• feel weak and tired (46)
• be breathless (48)
• feel full or uncomfortable because of a swollen liver or spleen (47)
• look very pale (47)
• develop bruises, nosebleeds or a rash of tiny red spots caused by bleeding under the skin (48)
• have frequent fevers and infections (47).

Treatment

If your HCL is not causing any symptoms, you are unlikely to have treatment straight away. Your doctor will monitor your health and keep treatment in reserve until you do have symptoms (49). Your doctor may call this ‘watch and wait’, ‘active monitoring’ or ‘active surveillance’. They all mean the same thing.

The main treatment for HCL is chemotherapy with a drug called a purine analogue. This works very well in almost all cases. After chemotherapy, most people have no hairy cells in their blood or bone marrow - complete remission - and go back to being monitored. If you have a partial remission, you have another course of chemotherapy (49).

In HCL, remission can last for many years (50). If you’ve been in remission for more than two years and your HCL comes back, your doctor will probably give you the same treatment you had the first time around. If your remission was shorter, you may have chemotherapy with a different purine analogue (51). In either case, you may have an immunotherapy drug as well (49,51).

In a small number of cases, the spleen can become very enlarged, causing discomfort and pain (47,49). If you have this, your doctor may suggest removing your spleen (49).

Outlook (prognosis)

With the treatments available now, most people live a long time with hairy cell leukaemia. Overall, around 95 out of 100 people diagnosed (95%) live for at least five years (50).

This figure does not mean people only live for five years. It relates to the number of people who are still alive five years after their diagnosis. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five-year survival’ is a commonly quoted statistic.

It is difficult to produce detailed statistics for a rare condition, but some research has shown very long remissions (50,52). Around half the patients they followed were still in remission (1) five years after treatment (50,52).