Lymphomas are the third most common type of childhood cancer, accounting for around 10 per cent of cases – 160 children every year in the UK.
There are two main types of lymphoma – Hodgkin and non-Hodgkin lymphoma.
Non-Hodgkin lymphoma is the slightly more common form, accounting for around three fifths of cases.
Lymphomas start in the lymphatic system, 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 cells can also spill into the blood stream and spread the cancer around the body, including to other lymph nodes.
Non-Hodgkin lymphoma 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.
Non-Hodgkin lymphoma (NHL)
There are 2 main types of NHL:
B-cell NHL usually affects the lymph nodes in the abdomen, head or neck. Burkitt lymphoma is a rare type of B-cell NHL.
T-cell NHL tends to occur in the chest and is more likely in teenagers.
Occasionally NHL can develop outside a lymph gland. This is called extranodal lymphoma.
The causes of NHL are not fully understood, however 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.
NHL accounts for about 60 per cent of lymphoma in children, with around 85 children affected each year in the UK.
NHL affects all ages but is very rare among infants; incidence increases until the age of around four years and remains fairly steady for the remaining years of childhood. The incidence among boys is more than twice that among girls.
NHL can be treated successfully in the majority of children, with an overall five year survival rate of 88 per cent.
The success of treatment depends on the type, stage and grade of the lymphoma. Better outcomes are associated with early diagnosis and disease localised to one area of the body.
Symptoms include a persistent (lasting a few weeks) painless swelling of a single lymph gland, usually in the neck.
Cough or breathlessness can occur if the glands in the chest are affected.
If the abdominal lymph glands are affected it may cause stomach pains, or change in the bowels.
Fevers, sweats, tiredness and weight loss can also occur.
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 and 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 stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. The type of treatment given depends on the stage of the disease. In simplified terms, the stages of NHL are as follows:
Stage 1 - one group of lymph nodes is affected, or there is a single extranodal tumour.
Stage 2 - two or more groups of nodes are affected, or there is a single extranodal tumour that has spread to nearby lymph nodes; or there are two single extranodal tumours, but only on one side of the diaphragm (the muscle that separates the chest cavity from the abdominal cavity).
Stage 3 - there is lymphoma on both sides of the diaphragm (either in two or more groups of nodes) or there are two single extranodal tumours or the lymphoma is affecting the chest.
Stage 4 - the lymphoma has spread beyond the lymph nodes to other organs of the body such as the bone marrow or nervous system.
The main treatment for non-Hodgkin lymphoma is chemotherapy. Rarely radiotherapy is also required.
The type and amount of treatment given depends on the stage of the disease at diagnosis. For example, treatment for B-cell NHL involves 4 to 8 courses of chemotherapy, but for T-cell NHL the treatment can last two years.
Treatment may be given into the spinal cord fluid (called intrathecal chemotherapy) to prevent spread of the cancer to the nervous system.
High dose chemotherapy with a stem cell (bone marrow) transplant may be used in NHL if the child relapses after initial treatment.
Read more: Commonly used terms in treatment
Side effects and complications
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
- Reduced resistance to infection
- Bruising and bleeding
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.
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: Side effects of treatment
Children will have regular follow-up appointments, following their treatment for Hodgkin lymphoma. These appointments are to check for any recurrence of the cancer and for any problems that may arise as a result of the treatment they were given (late effects).
Occasionally, the cancer can recur. When this happens it is called a relapse. Relapse occurs most likely as a result of a few of the original cancer cells surviving the treatment. Sometimes, this is because cancer cells spread to other parts of the body and were too small to be detected during the follow-up immediately after treatment.
Treatment of the relapse will vary and be discussed as it may differ from the original course of treatment. High dose chemotherapy with a stem cell (bone marrow) transplant may be used in relapsed NHL.
Read more: Long-term and late effects of treatment
Many children have their treatment as part of a clinical trial.
Trials aim to improve our understanding of the best way to treat the cancer, usually by comparing the standard treatment with a new or modified version.
If appropriate, the child’s medical team will discuss participation in a relevant trial. Participation is optional but may offer the opportunity to receive new treatments.
More detailed information about non-Hodgkin lymphoma in children and its treatment is available from Macmillan Cancer Support