Staging and prognosis for myeloma

Staging myeloma

The tests for myeloma allow your doctor to work out how far the myeloma has progressed. Called staging, this is an indication of how much the myeloma has affected your body and how it is likely to respond to treatment.

Blood cancers are staged differently to solid tumours like breast or lung cancer. Doctors look at blood test results rather than at the size and spread of the cancer. If you have any difficulty understanding the stage of the myeloma, ask your doctor to explain it in simple terms.

The most commonly used staging system for myeloma is the Revised International Staging System (R-ISS).

The R-ISS divides myeloma into three stages. Stage 1 is the earliest stage and stage 3 is more advanced.

The stages are based on the results of various blood tests that check:

• levels of beta-2 microglobulin (B2M) – a protein produced by myeloma cells that shows the extent of certain diseases
• levels of albumin – a protein produced by the liver that is a sign of overall health
• levels of lactate dehydrogenase (LDH) – an enzyme released into the blood when cells are damaged or destroyed
• genetic information – specific chromosomal abnormalities that identify people at risk of the disease progressing.

R-ISS staging system of myeloma

Stage 1

• B2M is less than 3.5 mg/L
• albumin level is 35 g/L or more
• LDH levels are normal
• genetic test results are considered not high risk

Stage 2   

• results higher than stage 1 but lower than stage 3

Stage 3

• B2M is 5.5 mg/L or more, either LDH levels are high or genetic test results are considered high risk

Significant signs of myeloma

Doctors usually use the CRAB system to help identify people with myeloma who need to start treatment. The SLiM criteria were added as part of staging and have three specific signs known as biomarkers. When used together, the criteria are known as the SLiM–CRAB criteria.

CRAB criteria: myeloma-defining events

• C – calcium levels in the blood are raised
• R  – renal (kidney) damage
• A – anaemia (low levels of red blood cells)
• B – bone pain and damage (areas of damage known as lytic lesions and/or bone loss known as osteoporosis can weaken bones making them more likely to fracture)

SLiM criteria: biomarkers of malignancy

• S – 60% or more abnormal plasma cells in the bone marrow (plasmacytosis)
• Li – light chain ratio (a high level of free light chains in the blood)
• M – MRI lesions (bone abnormalities found by MRI, CT or PET–CT of 5 mm or more in size)

When to start treatment

Test results will help your treatment team work out if, or when, you need to start any treatment.

Monoclonal gammopathy of undetermined significance (MGUS)

Test results

• no SLiM–CRAB features
• low level of paraprotein in blood or urine (less than 30 g/L)
• low level of myeloma cells in the bone marrow (less than 10% clonal plasma cells)

Need for treatment

• not cancer; needs active monitoring as it may progress to myeloma
• only about 1% of people with MGUS develop myeloma

Smouldering myeloma (asymptomatic myeloma)

Test results

• no SLiM–CRAB features
• paraprotein in blood (more than 30 g/L) or urine (more than 500 mg), and/or
• myeloma cells in the bone marrow (10–60% clonal plasma cells)

Need for treatment

• usually doesn’t need treatment straightaway
• may progress to active myeloma, needs active monitoring

Active myeloma (symptomatic myeloma)

Test results

• has SLiM–CRAB features
• high level of paraprotein in blood or urine
• one of the following: myeloma cells in the bone marrow (more than 60% clonal plasma cells); ratio of abnormal to normal light chains is less than 100; abnormal MRI with more than one (greater than 5 mm) focal lytic lesion (bone lesion)

Need for treatment

• active myeloma requires treatment

Prognosis

Prognosis means the expected outcome of a disease. It is not possible for any doctor to predict the exact course cancer will take, but your medical team can predict how the myeloma will respond to treatment based on several factors:

• your test results
• the type of myeloma you have, and its stage and rate of growth
• your age, fitness and medical history.

You will continue to have tests during treatment to check how well it’s working.

The outlook for people with myeloma is improving all the time. Even though treatment can’t cure myeloma, it can help control the disease (known as plateau phase or remission).

If the myeloma is under control, symptoms improve and people usually return to a state of good health that may last for months or a few years. For some people, the disease can be controlled for even longer periods.

When myeloma becomes active again it is called disease progression, or a relapse or recurrence. You will need to have further treatment when this happens.