Because more than one lymph node or other area can be involved, it is important to find out how extensive a lymphoma is. This process is called staging. The following table contains an example of the “Ann Arbor” staging classification system that describes how widespread the disease is. Ann Arbor staging is more useful in Hodgkin than in non-Hodgkin lymphoma.
Stages Found in Lymphomas
|I||Stage I occurs when there is a single lymphoid area (such as the spleen), a pair of areas (tonsils), or a group of related areas (the tonsils and adenoids) involved.|
|II||Stage II occurs when there are two or more lymphoid areas involved, but they are on the same side of the diaphragm (the muscle under the rib cage that controls breathing). An example of this would be the tonsils and one underarm lymph node.|
|III||Stage III occurs when there is involvement on both sides of the diaphragm, such as a node in the neck and another in the abdomen.|
|IV||Stage IV has involvement throughout the body and, in particular, in major sites such as the bone marrow.|
A more useful staging system for prognosis is the “International Prognostic Index” of IPI. This scores one point each for
- Age over 60
- Ann Arbor stage 3 or 4 disease
- More than one non-nodal site involved (for example, bone marrow, liver or lung)
- High serum LDH
- an ECOG score greater than 1 (feeling unwell enough to spend a proportion of the day in bed resting).
Staging allows the physician to determine what choices of therapy are available. For example, localised disease may be cured by surgery or radiotherapy, with or without chemotherapy. More advanced disease may require chemotherapy. In some circumstances, chemotherapy may also have to be given into the fluid around the spinal cord (intrathecal chemotherapy, by lumbar puncture) to reduce the risk of spread of lymphoma to the brain.
The most commonly used staging tests performed in the clinical laboratory are the FBC, liver and kidney function studies, and bone marrow biopsy. Non-laboratory tests may include ultrasound, CT, MRI and PET scans.