Lymphomas

18 March 2012

Lymphomas are cancers that account for about 10 per cent of childhood cancer cases – around 160 each year in Britain.

Lymphomas start in the lymphatic system. The lymphatic system is the network of vessels that runs throughout the body carrying fluid containing white blood and other important immune system cells. Lymph nodes respond to infections by releasing white blood cells called lymphoid cells into the blood stream to fight it off.

When someone has lymphoma, lots of abnormal lymphoid, or lymphoma, cells are produced within a particular lymph node.

These are the same cells that become cancerous in people who have leukaemia, another form of blood cancer. The difference is that leukaemia develops in the bone marrow and affects normal blood cell production. Lymphoma, on the other hand, develops in the lymphatic system and does not affect normal blood cell production.

In patients with lymphoma the cancer cells cluster in the lymph nodes and form tumours. These can also spill into the blood stream and spread the cancer around the body, including to other lymph nodes.

What is the difference between Hodgkin and non-Hodgkin lymphoma?

There are two main types of lymphoma – Hodgkin and non-Hodgkin.

Hodgkin lymphoma is slightly less common, accounting for around two-fifths of childhood lymphomas. It is distinguished from other types of lymphoma by the type of cancer cell formed – the Reed-Sternberg cell – which is not found in any other blood cancer.

Non-Hodgkin lymphoma (NHL) can affect any lymph node or related tissue in the body whereas Hodgkin lymphoma tends to affect the lymph nodes in the head and neck.

Incidence

Around 160 children are diagnosed with lymphoma every year in Britain – 10 per cent of all cancer diagnoses.

Hodgkin lymphomas account for 41 per cent of all childhood lymphoma diagnoses – 64 children a year in Britain. They predominantly affect older children, with two thirds of cases occurring in the 10-14 year age group and no registrations for infants. Hodgkin lymphomas are almost twice as common among boys as among girls.

NHL accounts for almost all of the remaining cases. NHL is very rare among infants; incidence increases quite sharply until the age of four years and remains fairly steady for the remaining years of childhood. The incidence among boys is more than twice that among girls.

Causes

There is no single cause of lymphoma and in most cases it is probably down to a combination of factors, including genetics and infection with specific bacteria and viruses.

The exact cause of Hodgkin lymphoma is unknown. However, there is increasing evidence that infections (such as the virus that causes glandular fever) may play a part in its development. It has been reported to occur more frequently among young children from developing countries than among those from countries of advanced socio-economic status. There is an increased risk of the disease among parents, siblings and identical twins.

Children with deficiencies of the immune system or who have been taking immunosuppressing drugs for a long-time are known to be at increased risk of NHL.

Both Hodgkin and non-Hodgkin lymphoma have been linked with the Epstein-Barr virus (EBV), however EBV is extremely common and most people who get it do not develop lymphoma.

Several geographical areas are associated with particular types of lymphoma – such as the ‘endemic’ Burkitt lymphoma in Africa.

Survival

Survival rates for childhood lymphomas are good: 95 per cent for Hodgkin lymphoma and 83 per cent for NHL.

Diagnosis and treatment

The exact diagnosis will be confirmed by removing part or all of an affected lymph gland so that the cells can be examined in the laboratory. This is known as a biopsy; it is usually carried out under general anaesthetic.

Further tests, such as x-rays, CT and MRI scans and blood tests, are carried out to determine the exact size and position of the lymphoma and whether it has spread. This is known as staging.

The main treatment for both Hodgkin and non-Hodgkin lymphoma is chemotherapy. Sometimes radiotherapy is also required. If the cancer has not spread beyond its original site, radiotherapy alone may be used, following surgery to remove the affected lymph nodes. The type and amount of treatment given depends on the stage of the disease at diagnosis.

Where chemotherapy is used, it will usually be given every few weeks for a number of months. High dose chemotherapy with a stem cell (bone marrow) transplant may be used in NHL if the child relapses after initial treatment.

Where radiotherapy is used, it is usually given for a few minutes each day over a period of two to four weeks.

Treatment may last for anything between a few months and two years, depending on the exact type of lymphoma and the stage to which it has progressed.

Side effects of treatment

Treatment often causes side effects. These will depend on the particular treatment being used and the part of the body being treated but may include:

Hair loss
Tiredness
Nausea
Vomiting
Reduced resistance to infection
Bruising and bleeding
Diarrhoea

Read more: Side effects of treatment

Late effects of treatment

A small number of children may develop late side effects, sometimes many years later, that are caused by their treatment for lymphoma.

The main risks arise from the use of radiotherapy, which may impair growth and cause infertility. The risk of infertility is greater among boys and the risk is increased if both radiotherapy and chemotherapy are used.

There is a risk of hypothyroidism associated with irradiation to the neck.

Both radiotherapy and chemotherapy have been associated with heart and lung complications.

There is an increased risk of second cancers in those who survive childhood cancer, thought to be associated with the treatments used.

The possible risks of any treatment given will be explained by the child’s doctor before treatment begins. Every effort will be made to minimise the risk of these kinds of complications.

Read more: Long-term and late effects of treatment

References:
Cancer in Children: Clinical Management (5th edition). Eds: P A Voute, Ann Barrett, Michael C G Stevens and Hubert N Caron. Oxford University Press, 2005.
Childhood Cancer in Britain: incidence, survival, mortality. Ed by Charles Stiller. Oxford University Press, 2007.
Macmillan Cancer Support factsheet - Hodgkin lymphoma in children (2010)
Macmillan Cancer Support factsheet - non-Hodgkin lymphoma in children (2010)

Related Topics Lymphomas, types of childhood cancer

Categories types of childhood cancer