What is Myeloma?
Myeloma (from ancient Greek. – bone marrow and ending in the names of tumors), Rustitsky-Kalera disease, multiple myeloma, generalized plasma cytoma – a disease of the blood system, related to paraproteinemic leukemia. The name of the disease and tumor cell received in connection with the predominant localization of the process on the “territory” of the bone marrow.
Causes of Myeloma
Most people get sick in old age. Cases of the disease before the age of 40 years are rare.
The incidence of multiple myeloma is 3 per 100,000 population per year; men get sick more often.
Pathogenesis during Myeloma
Tumor tissue grows mainly in the flat bones (skull, ribs, pelvis) and in the spine, initiating osteolysis and osteoporosis in them. On the radiograph, the lesions have the appearance of smooth-wall holes. Cavities are formed in places where myeloma cells grow due to the activation of osteoclasts, which carry out lysis and resorption of bone tissue (axillary resorption). In addition to bone marrow, tumor infiltrates can be found in other organs.
Symptoms of Myeloma
There are several variants of myeloma, depending on the nature of the spread of myeloma infiltrates in the bone marrow, on the nature of myeloma cells and on the type of paraprotein synthesized.
- By the nature of the prevalence of tumor infiltration in the bone marrow emit:
– diffuse,
– diffuse nodular,
– multiple nodular myeloma; - cell composition:
– plasmacytic,
– plasmablastic,
– polymorphic-cellular,
– small cell myeloma. - Depending on the ability to secrete various types of paraproteins, there are several variants of myeloma: non-secretion, diclon myelomas, Bens-Jones myeloma, G-, A-, M-myeloma. The most common are G-, A-myeloma, Bens-Jones myeloma, which account for 75, 20, and 15% of cases, respectively.
Complications of multiple myeloma develop due to the destruction of bone tissue – spontaneous fractures, bone pain, and also due to the production of paraproteins – amyloidosis (AL-amyloidosis), paraproteinemic coma and paraproteinosis of the organs.
Sometimes there are tumors emanating from the bone tissue. Due to the destruction of bones in the blood, the amount of calcium increases, which in the form of calculus is deposited in the excretory organs (kidneys, lungs, and mucous gland). Kidney damage (myeloma nephropathy) is mainly due to the paraprotein inflow through the renal filter. Characteristic of myeloma is the frequency of bacterial infections due to a decrease in the number of normal immunoglobulins and impaired antibody production.
Treatment of Myeloma
Establishing a diagnosis of multiple myeloma implies the need to start treatment. Expectant tactics are justified in case of indolent (sluggish) myeloma, when there are no clinical manifestations of the disease. These patients are shown dynamic observation and treatment begins in the case of progression of the disease. The main criterion for the need for specific therapy of multiple myeloma is the presence of target organ damage. In normal clinical practice, the acronym (a word composed of the first letters of a few words) “CRAB” is used to determine the indications for initiating therapy: calcemia (hypercalcemia), renal insufficiency (renal failure), anemia (anemia), bone lesions (bone damage). Currently, there is no single treatment concept for multiple myeloma.
Chemotherapy
Chemotherapy is the primary treatment.
- Monochemotherapy
Melphalan
Most authors recommend the following MP (M + P) regimen: melphalan 0.25 mg / kg (9 mg / m2) orally daily 1–4 days, prednisone 1-2 mg / kg orally daily 1–4 days. Interval between courses 4-6 weeks. The scheme of MP can look like this: melphalan 6-10 mg orally daily 1-7 or 1-10 days, prednisone 60 mg orally daily 1-7 or 1-10 days. The interval between courses is 4-6 weeks and is determined by the severity of myelotoxicity. A positive clinical response to therapy under the MP program is noted in 50-60% of patients with multiple myeloma, however, PR is achieved in 0-3% of patients. The overall survival of patients with MM who received MP therapy averages 29 months.
Cyclophosphamide
The following regimen is most often used: cyclophosphamide 400 mg every other day or 200 mg daily or 300 mg / m2 once a week to a course dose of 6-10 g. Cyclophosphamide therapy is carried out either as monotherapy or in combination with prednisone in the above doses. - Polychemotherapy according to the M² and VAD programs is used in patients with a more common disease and a worse prognosis; however, according to most researchers, these programs do not exceed the M + P scheme in either the number of remissions, or their duration, or overall survival.
- Α-interferon preparations are usually used during the plateau phase of chemotherapy. This significantly increases the duration of remission.
- In patients of a young age with a poor prognosis, high-dose chemotherapy is performed, followed by allo- and autotransplantation of red bone marrow. This method of treatment increases recurrence-free and overall survival.
Symptomatic treatment
Adequate correction of hypercalcemia, the use of analgesics, hemostatic therapy, orthopedic care.
Surgery
It is indicated for solitary myeloma, signs of compression of vital organs.
Radiation therapy
It is shown as palliative treatment in debilitated patients, in case of renal failure and tumor resistance to chemotherapy. It is also possible to use for local bone lesions.