Multiple Myeloma

Diagnosis

Mayo Clinic has developed systems for classifying newly diagnosed myeloma. These systems help tailor treatment to patients' needs and enable a more accurate prognosis of the course of the disease.

Patients are first tested for the presence of monoclonal proteins, or M proteins, in their blood and urine. Myeloma cells are known to produce an unusual amount of M proteins — also known as M-spike when found in blood or Bence Jones protein when found in urine.

To ensure accuracy, Mayo's tests require a 24-hour urine collection. Additional blood and urine tests are usually done to fine-tune the diagnosis and enhance the hematologist's ability to monitor the patient's response to treatment. About 1 to 2 percent of patients with myeloma have no M proteins, and are diagnosed as having nonsecretory myeloma.

A bone marrow biopsy determines the extent of bone marrow involvement (tumor burden), the presence of cell-development abnormalities, and whether the patient's plasma cells are multiplying abnormally. X-rays are taken to check for lytic lesions, weakened areas of bone associated with the concentration of myeloma cells. Patients whose X-rays do not show lesions, but who nonetheless have bone pain, are given CT, PET-CT or MRI scans.

Plasma cells must comprise at least 10 percent of a patient's bone marrow for a diagnosis of multiple meyloma. Patients also must have M protein in the blood or urine (except in nonsecretory cases) and evidence of organ damage (low hemoglobin, lytic bone lesions, increased blood calcium or kidney failure) related to the plasma-cell disorder.

Risk Levels

After testing, patients are classified within a new International Staging System (ISS) developed by Mayo Clinic in collaboration with other institutions. Using ISS and other factors, patients are further classified as having high-risk or standard-risk myeloma, according to the mSMART (Mayo Stratification for Myeloma and Risk-adapted Therapy) model also developed by Mayo. Between 25 and 30 percent of patients are stratified as high-risk.

Patients who have M protein in their blood or urine but who do not have myeloma may be diagnosed with monoclonal gammopathy of undetermined significance (MGUS) or smoldering multiple myeloma. Discovered by Mayo Clinic researchers, these precancerous conditions can progress to multiple myeloma but do not require treatment.