- What is Waldenström macroglobulinemia?
Waldenström macroglobulinemia (WM) is a rare, indolent
(slow-growing) non-Hodgkin lymphoma (cancer that begins in the cells of the
immune system). WM is also called lymphoplasmacytic
lymphoma. It starts in white
blood cells called B
lymphocytes or B cells.
B cells are an important part of the body’s immune system. They form
in the lymph nodes, spleen,
and other lymphoid
tissues,
including bone
marrow (the soft, spongy tissue inside bones). Some B cells become plasma
cells, which make, store, and release antibodies. Antibodies help the body
fight viruses,
bacteria,
and other foreign substances.
Lymphoplasmacytic cells are cells that are in the process of maturing from
B cells to plasma cells. In WM, abnormal
lymphoplasmacytic cells multiply out of control, producing large amounts of
a protein called monoclonal immunoglobulin M (IgM or “macroglobulin”)
antibody. High levels of IgM in the blood cause hyperviscosity (thickness
or gumminess), which leads to many of the symptoms of WM (see Question
4).
- How often does Waldenström macroglobulinemia occur?
WM is a rare cancer; about 1,500 new cases occur annually in the United
States. The incidence
of WM is higher in males and higher in whites than in African Americans. Incidence
increases sharply with age. The median
age at diagnosis
is 63 (half of the cases are diagnosed before age 63, and half are diagnosed
after age 63) (1).
- What are the possible causes of Waldenström macroglobulinemia?
The exact cause of WM is not known. However, scientists believe that genetics
may play a role in WM, because the disease has been seen to run in families
(1).
- What are the symptoms of Waldenström macroglobulinemia?
Some patients do not have symptoms. For those who do have symptoms, the
most common ones are weakness, severe fatigue, bleeding from the nose or gums,
weight loss, and bruises or other skin lesions.
Severely high levels of IgM can lead to hyperviscosity
syndrome, in which
the blood becomes abnormally thick. Symptoms of this syndrome include visual
problems (e.g., blurring or loss of vision) and neurological problems (e.g.,
headache, dizziness, vertigo). During a physical
exam, a doctor may also find swelling of the lymph nodes, spleen, and/or
liver
(2).
- How is Waldenström macroglobulinemia diagnosed?
Initial diagnosis of WM is based on blood
test and bone marrow biopsy results. Blood tests are used to determine
the level of IgM in the blood and the presence of proteins, or tumor
markers, that can indicate WM. For the biopsy,
a sample of bone marrow (soft, sponge-like tissue in the center of most bones)
is removed, usually from the back of the pelvis
bone, through a needle for examination under a microscope. The pathologist
(a doctor who identifies diseases by studying cells and tissue under a microscope)
looks for certain types of lymphocytes
(white blood cells) that indicate WM (1). Flow
cytometry (a method of measuring cell properties using a light-sensitive
dye and laser
or other type of light) is often used to look at markers
on the cell surface or inside the lymphocytes.
Additional tests may be recommended to confirm the diagnosis. A computed
tomography (CT
or CAT) scan uses a computer linked to an x-ray
machine to create pictures of areas inside the body. This test may be used
to evaluate the chest, abdomen,
and pelvis, particularly swelling of the lymph nodes, liver, and/or spleen
(1). A skeletal
survey (x-rays of the skeleton)
can help distinguish between WM and a similar plasma
cell cancer, multiple
myeloma (1).
- How is Waldenström macroglobulinemia treated?
At this time, there is no known cure
for WM. However, several treatment options are available to prevent or control
the symptoms of the disease.
Patients who do not have symptoms of WM are usually monitored without being
treated; these patients often live for many years before requiring treatment
(2). Patients with symptoms are usually treated with chemotherapy.
Biological
therapy (treatment that stimulates the immune system to fight cancer)
is also used to treat WM (3). Promising results have been
seen with biological therapy and chemotherapy in combination. An example of
combination therapy
uses rituximab
and fludarabine
(4). Patients with high levels of IgM and hyperviscosity
syndrome may undergo plasmapheresis. In this procedure, blood from the patient
is removed and circulated through a machine that separates the plasma (which
contains the antibody IgM) from other parts of the blood (red
blood cells, white blood cells, and platelets).
The red and white blood cells and platelets are returned to the patient, along
with a plasma substitute (4). Plasmapheresis is often followed
by chemotherapy.
Because WM is rare, some doctors may suggest treatments that have been effective
in some cases but are not considered standard
treatment and/or are under study in clinical trials (research studies).
Some of these treatments include (4):
- High-dose
chemotherapy with autologous
stem cell transplantation— blood-forming stem
cells (cells from which all blood cells develop) are harvested (removed)
and stored, then given back to the patient following high-dose chemotherapy.
The harvested cells may be treated before transplantation
to get rid of cancer cells. The transplanted cells travel to the bone marrow
and begin to produce new blood cells.
- Splenectomy—surgery
to remove the spleen. This procedure has been used in WM patients who have
a significantly enlarged spleen. Occasionally, WM patients who have had
this procedure have experienced remissions (decrease in or disappearance
of signs or symptoms of cancer) lasting for many years. The remissions are
believed to be due to the removal of a major source of IgM production.
- Thalidomide
and bortezomib—drugs
used to treat multiple myeloma, a disease similar to WM. Side effects of
thalidomide include constipation,
weakness, and peripheral
neuropathy (a problem in nerve
function that causes pain, numbness, tingling, swelling, and muscle weakness).
Both agents are currently being studied in clinical trials for WM.
- Are clinical trials (research studies) available? Where
can people get more information about clinical trials?
Yes. The National Cancer Institute (NCI),
a component of the National Institutes of Health, is sponsoring clinical trials
that are designed to find new treatments and better ways to use current treatments.
Before any new treatment can be recommended for general use, doctors conduct
clinical trials to find out whether the treatment is safe for patients and
effective against the disease. Participation in clinical trials may be a treatment
option for patients with WM.
People interested in taking part in a clinical trial should talk with their
doctor. Information about clinical trials is available from the NCI’s
Cancer Information Service (CIS)
(see below) at 1–800–4–CANCER and in the NCI booklet Taking
Part in Cancer Treatment Research Studies, which can be found at http://www.cancer.gov/publications
on the Internet. This booklet describes how research studies are carried out
and explains their possible benefits and risks. Further information about
clinical trials is available at http://www.cancer.gov/clinicaltrials
on the NCI’s Web site. The Web site offers detailed information about
specific ongoing studies by linking to PDQ®,
the NCI’s comprehensive cancer information database. The CIS also provides
information from PDQ.
