The stage of a cancer is a term used to describe its size and whether it has spread beyond its original area. Knowing the extent of the cancer and the type (see opposite) helps the doctors to decide on the most appropriate treatment. The most commonly used staging system for Hodgkin lymphoma is outlined below:

Stage 1 One group of lymph nodes is affected

Stage 2 Two or more groups of lymph nodes are affected on the same side of the diaphragm (the sheet of muscle underneath the lungs)

Stage 3 Lymph nodes above and below the diaphragm are affected

Stage 4 The lymphoma has spread outside the lymph glands to organs such as the liver, bones or lungs.

If the Hodgkin lymphoma comes back after initial treatment, this is known as recurrent lymphoma.

As well as giving each stage a number, doctors also use a letter code – either A or B – to show whether or not you have specific symptoms. Your doctor will ask you whether you have lost a significant amount of weight or have fever or night sweats. If you have none of these symptoms your lymphoma will be classified as A. If you have one or more of them it is classified as B.