Staging of myeloma

The stage of a cancer is a term used to describe its extent and how much it is affecting the body. Knowing the extent of the myeloma helps doctors to decide on the most appropriate treatment.

Generally, myeloma is divided into three stages, which indicate the effect the disease is having on the body and how quickly or slowly it may develop. A commonly used staging system for myeloma, known as the Durie-Salmon system, is described below.

This staging system is based upon how the disease is affecting the:

• red blood cells (haemoglobin, Hb)
• calcium level in the blood
• amount of paraproteins
• bones.

Stage 1 The myeloma is at an early stage. The number of red blood cells is either normal or only slightly reduced. The amount of calcium in the blood is normal. There are low levels of paraproteins in the blood or urine. The bones either appear normal or there is a single plasmacytoma. There may be no symptoms.

Stage 2 The myeloma is at an intermediate stage, between stage 1 and stage 3.

Stage 3 The myeloma is at a more advanced stage. It has caused one or more of the following:

• the haemoglobin has dropped to quite a low level and anaemia is quite severe
• the level of calcium in the bloodstream has risen greatly
• three or more bones are affected and fractures may occur
• there are high levels of paraproteins in the blood or urine.

Stages 2 and 3 are also further divided depending upon how well the kidneys are working. As well as a number, the different stages are given a letter, either A or B. For example, you may have stage 2A or 3B.

A Kidney function is normal, or little affected by the myeloma.

B Kidney function is abnormal.

A second staging system for myeloma, that has recently been developed, looks at the levels of particular blood proteins: beta-2 microglobulin and albumin. This newer staging system, known as the International Staging System, also contains three stages. It can help doctors to stage the myeloma more accurately.

Stage I The beta-2 microglobulin is less than 3.5mg/L and the albumin level is greater than or equal to 3.5g/dL.

Stage II Both the beta-2 microglobulin level and the albumin levels are less than 3.5, or the beta-2 microglobulin level is between 3.5 and 5.5mg/L.

Stage III The beta-2 microglobulin level is greater than or equal to 5.5 mg/L.

If myeloma comes back after initial treatment it is known as relapsed or recurrent myeloma.