Encyclopedia of Health and Medicine

multiple myeloma 159
presses the maturation of lymphocytes to plasma
cells. Thalidomide analogs (such as Revimid and
Actimid) are drugs closely related in chemical
structure to thalidomide. Oncologists may administer
thalidomide in combination with prednisone
or dexamethasone, corticosteroid medications that
help suppress bone marrow activity to slow the
production of cancerous plasma cells.
Proteasome inhibitors In 2003 the US Food
and Drug Administration (FDA) approved the proteasome
inhibitor bortezomib (Velcade) for people
who have experienced two relapses following conventional
treatment approaches. Proteasome
inhibitors block the actions of enzymes within
cells that are crucial to the cell’s ability to divide
(reproduce). Clinical studies continue to investigate
the effectiveness of these drugs, which appear
to cause fewer side effects than conventional
chemotherapy, as first-choice treatment.
Bone marrow and stem cell transplantation
Autologous BONE MARROW TRANSPLANTATION or STEM
CELL transplantation (self-transplantation with
harvested cells), achieves remission in many people.
For autologous transplantation, the oncologist
harvests peripheral BLOOD STEM CELLS (PBSC) or
stem cells from healthy areas of bone marrow;
administers high-DOSE chemotherapy after cell
harvesting to kill the cancerous bone marrow; and
administers the harvested bone marrow or stem
cells, which then grow to replace the cancerous
bone marrow. Allogeneic stem cell transplantation,
which uses stem cells from a tissue-matched
donor, carries relatively high risks of complications
including transplant rejection, infection, and other
reactions, but is so far the only hope for a cure
of multiple myeloma. Nonmyeloablative (the
patient’s bone marrow is not destroyed) allogeneic
stem cell transplantation reduces the high risks of
high-dose chemotherapy. Though not curative it
may offer increased survival time.
Adjunctive therapies Oncologists use various
medications to mediate the side effects of treatment
as well as the complications that arise as the
course of the cancer progresses. Among them are:
• Statins (such as Lipitor and Mevacor) counters
the osteoclastic (bone destruction) stimulation
M-proteins generate. Researchers discovered in
the early 2000s that the statin medications used
to treat HYPERLIPIDEMIA (elevated blood cholesterol
and blood lipid levels) additionally stimulate
osteoblastic (bone construction) activity,
resulting in increased production of new bone
tissue.
• Therapeutic EPO supplementation (Procrit)
stimulates bone marrow production of erythrocytes,
relieving anemia.
• Bisphosphonates bind to damaged bone cells
and so prevent further osteoclastic action
(destruction). This allows the body’s natural
bone remodeling mechanisms to repair the
damage and rebuild the bone. However, bisphosphonates
present the potential for serious
kidney damage.
• ANTIBIOTIC MEDICATIONS aggressively treat the
infections that become increasingly common as
dysfunction of the IMMUNE SYSTEM progresses.
Lifestyle factors Because multiple myeloma
affects bone remodeling, daily weight-bearing
exercise such as walking is important to stimulate
the body’s normal osteoblastic (bone-constructing)
mechanisms. These mechanisms further help bone
tissue retain calcium, reducing the amounts of calcium
that leaches into the circulation. Drinking
lots of water to maintain high HYDRATION is also
especially important. Staying well hydrated helps
offset the tendency of the blood to become hyperviscous
(thickened) as a consequence of the
changes in its constitution that take place with the
multiple myeloma. It also helps protect the kidneys
by lowering the concentration of calcium and
M-proteins that they must filter from the blood
and pass in the URINE. Nutritious EATING HABITS provide
the body with the NUTRIENTS it needs to maintain
the best health status possible.
Risk Factors and Preventive Measures
Though environmental exposure, notably to pesticides
and radiation, appears to play a role in the
development of multiple myeloma, researchers do
not know the mechanisms of such exposure.
Many people who develop multiple myeloma do
not have a known history of exposure to substances
so far linked with an increased risk for this
form of cancer, making it difficult for health