Lymphoma

Lymphoma is a cancer of the lymphatic system. The lymphatic system is made up of a series of vessels and glands, known as lymph nodes. These are spread throughout your body, much like your blood vessels.

The lymphatic system is part of your immune system. It carries lymph around your body. Lymph is a fluid full of infection-fighting white blood cells known as lymphocytes.

In lymphoma, these lymphocytes begin reproducing in an abnormal manner and begin to collect in certain parts of the lymphatic system, such as the lymphatic nodes.

The affected lymphocytes begin to lose their infection-fighting properties, making you more vulnerable to infection.

The causes of lymphoma are still unknown.

Types of lymphoma

There are two main types of lymphoma:

• Hodgkin's lymphoma, and
• non-Hodgkin's lymphoma.

Hodgkin's lymphoma

Hodgkin's lymphoma is named after the doctor who was the first person to describe the condition, during the 19th century. Hodgkin's lymphoma is characterised by a distinctive altered (mutated) cell known as a Reed-Sternberg cell.

Hodgkin's lymphoma is one of the rarer types of lymphoma. There are an estimated 1,300-1,500 new cases of Hodgkin's lymphoma in the UK every year. The condition mostly affects young adults, aged between 15 and 35, and older adults over the age of 50. Hodgkin's lymphoma affects more men than women.

Hodgkin's lymphoma is a relatively aggressive cancer and can quickly spread through the body. Despite this, it is also one of the most easily treated types of cancer.

Almost 100% of young people with Hodgkin's lymphoma will achieve a full cure. For older people over the age of 50, the cure rate is around 75-80%.

Non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma is a general term to refer to any type of lymphoma that does not have the distinctive Reed-Sternberg cell.

There are many sub-types of non-Hodgkin's lymphoma, but they can all be put into one of two broad categories:

• High-grade or aggressive non-Hodgkin's lymphoma. These are lymphomas where the cancer develops quickly and aggressively.
• Low-grade or indolent non-Hodgkin's lymphoma. These are lymphomas where the cancer develops slowly, and you may not experience any symptoms for many years.

There are an estimated 8,500 to 9,000 new cases of non-Hodgkin's lymphoma in the UK every year. The condition is associated with ageing, as the chances of developing the condition increase as you get older. The average age at diagnosis is around 65.

For reasons that are not understood, the rates of new cases of non-Hodgkin's lymphoma have been slowly but steadily rising for the last 50 years. The rate of increase in the UK is around 4% a year. If rates of non-Hodgkin's lymphoma continue to rise at the current rate, it is estimated that it will be as common as breast or lung cancer by 2025.

Despite their respective names, high-grade non-Hodgkin's lymphoma is easier to treat than low-grade non-Hodgkin's lymphoma. Cure rates depend on individual circumstances and the sub-type of the lymphoma, but an average of 60% of people with high-grade non-Hodgkin's lymphoma are cured.

The problem with low-grade non-Hodgkin's lymphoma is that it doesn't cause symptoms until it's well advanced, by which time it's often too late to cure. However, it's possible to control symptoms for many years.