Multiple Myeloma (MM)

Multiple myeloma is a type of cancer due to an excessive production of malignant plasma cells. Plasma cells produce a type of proteins called antibodies or immunoglobulins. The proliferation of these proteins infiltrates the bone marrow.

As a result of this proliferation, there is a destruction of bone marrow (soft tissue responsible for producing blood cells), bones, and kidneys. This destruction leads to the different signs and symptoms of the disease.

Multiple myeloma is a type of blood or hematologic cancer (malignant tumors that affect the production and function of blood cells).

The causes of multiple myeloma are still unknown.

Multiple myeloma represents 1% of malignant tumors and 10% of hematological malignancies.

The incidence of the disease is approximately 50 cases per year per million population. The average age of the diagnosis is 65 years.

It has a worldwide distribution and affects mainly black and Afro-American people.

The malignant plasma cells produce a type of proteins known as immunoglobulins or antibodies.

Multiple myeloma can be classified into different types based on the immunoglobulin (protein) produced by the myeloma cell.

• Immunoglobulin G (IgG, 55% the most common)
• Immunoglobulin A (IgA, the second most common 30%)
• Immunoglobulin kappa or lambda
• Immunoglobulin M (IgM)
• Immunoglobulin D (IgD)
• Immunoglobulin E (IgE)
• Biclonal (dominance of 2 types of proteins)

Multiple myeloma is usually asymptomatic. The diagnosis is usually incidentally when a blood test with serum protein electrophoresis is performed.

The most common symptom related to multiple myeloma when they are present are:

• Bone pain (particularly in the spine and long bones)
• Chronic anemia
• Leukopenia and thrombocytopenia (decreased white blood cells and platelets)
• Hypercalcemia (a high calcium level in the blood)
• Kidney failure
• Recurrent infections
• Constitutional or nonspecific symptoms (fatigue, weakness, weight loss, loss of appetite)
• Neurological symptoms (from spinal cord compression)

A patient with multiple myeloma must be adequately diagnosed. For this matter, a group of tests is required.

Blood and urinalysis:

• Blood count, biochemistry and coagulation test
• ESR (Erythrocyte Sedimentation Rate) and CRP (C-reactive Protein)
• Serum protein electrophoresis.
• Beta-2 microglobulin protein
• Urinalysis

Imaging tests:

• Bone X-ray (complete radiological study of the body looking for bone damage)
• Computed tomography (CT)
• Nuclear magnetic resonance (NMR)

Anatomical Pathology:

• Bone marrow biopsy and aspiration

Treatment should include the possibility to receive an autologous hematopoietic cell transplant (the target for this treatment are people younger than 65-70 years with no severe disease).

The patients under this type of therapy will receive several treatment cycles of Bortezomib or Lenalidomide along with Dexamethasone. Later, the autologous transplant will be performed.

In case of failure of the first autologous transplant, a second try is possible.

For those who are not adequate for the autologous hematopoietic cell transplant, the better treatment is the administration of Melphalan, Prednisone and Bortezomib or Lenalidomide.

Complementary measures:

• Adequate fluid intake to avoid kidney damage.
• Analgesia (pain relievers) for bone pain.
• Bisphosphonates: Recommended in patients undergoing chemotherapy to prevent spinal fractures.
• Erythropoietin (EPO): In case of anemia.
• Influenza vaccine, pneumococcal vaccine and Haemophilus influenzae vaccine.
• Corticosteroids (Dexamethasone) in case of spinal cord compression.
• In case of hypercalcemia, appropriate hydration and forced diuresis with Furosemide.

The prognosis is variable. Some patients remain asymptomatic and require no treatment for many years, whereas others get worse quickly despite a proper treatment.