The term
lymphoma
refers to cancers that originate in the body's
lymphatic
tissues. Lymphatic tissues include the lymph nodes (also called
lymph glands), thymus, spleen,
tonsils
,
adenoids
, and bone marrow, as well as the channels (called lymphatics or
lymph vessels) that connect them. Although many types of cancer
eventually spread to parts of the lymphatic system, lymphomas are
distinct because they actually originate there.
About 1,700 kids younger than 20 years old are diagnosed with
lymphoma each year in the United States. Lymphomas are divided into
two broad categories, depending on the appearance of their
cancerous (malignant) cells. These are known as Hodgkin disease and
non-Hodgkin lymphoma (NHL). Together, they are the third most
common type of cancer in children.
Hodgkin Disease
This type of lymphoma is defined by the presence of specific
malignant cells, called Reed-Sternberg cells, in the lymph nodes or
in some other lymphatic tissue. Hodgkin disease affects about 3 out
of every 100,000 Americans, most commonly during early and late
adulthood (between ages 15 and 40 and after age 55).
The most common first symptom of Hodgkin disease is a painless
enlargement of the lymph nodes (a condition known as swollen
glands) located in the neck, above the collarbone, in the underarm
area, or in the groin.
If cancer involves the
thymus
(a gland of the immune system that is larger in children and
located in the middle of the chest), pressure from this gland may
trigger an unexplained cough, shortness of breath, or problems in
blood flow to and from the heart.
About a third of patients have other nonspecific symptoms,
including fatigue, poor appetite, itching, or hives. Unexplained
fever, night sweats, and weight loss are also common.
Non-Hodgkin Lymphoma (NHL)
There are about 500 new cases of non-Hodgkin lymphoma diagnosed
each year in kids in the United States. It may occur at any age
during childhood, but is rare before age 3. NHL is slightly more
common than Hodgkin disease in kids younger than 15 years old.
In non-Hodgkin lymphoma, there is malignant growth of specific
types of
lymphocytes
(a kind of white blood cell that collects in the lymph nodes).
Malignant growth of lymphocytes is also seen in one of the forms of
leukemia
(acute lymphoblastic leukemia, or ALL), which sometimes makes it
difficult to distinguish between lymphoma and leukemia in children.
In general, people with lymphoma have no or only minimal bone
marrow involvement, whereas those with leukemia have extensive bone
marrow involvement.
The development of some types of NHL, such as Burkitt's
lymphoma, may have some link to the Epstein-Barr virus (the cause
of infectious
mononucleosis
, or mono). Pieces of viral genetic material have been detected in
some cells taken from patients with NHL.
Risk for Childhood Lymphoma
Both Hodgkin disease and NHL tend to occur more often in white
males and in people with certain severe immune deficiencies -
including people with inherited immune defects, adults with
human immunodeficiency virus (HIV)
infection, or those who have been treated with immunosuppressive
drugs after organ transplants.
Although no lifestyle factors have been definitely linked to
childhood lymphomas, kids who have received either radiation
treatments or chemotherapy for other types of cancer seem to have a
higher risk of developing lymphoma later in life.
In most cases, neither parents nor kids have control over the
factors that cause lymphomas. Most lymphomas come from noninherited
mutations (errors) in the genes of growing
blood cells
. Regular pediatric checkups can sometimes spot early symptoms of
lymphoma in the relatively rare cases where this cancer is linked
to an inherited immune problem, HIV infection, prior cancer
treatment, or treatment of immunosuppressive drugs for organ
transplants.
Diagnosis
The doctor will check your child's weight and perform a
physical examination to look for enlarged lymph nodes and signs of
local infection. He or she will also examine your child's chest
using a stethoscope and will feel the abdomen to check for pain,
organ enlargement, or fluid accumulation.
In addition to doing a physical exam, the doctor will take
a
medical history
by asking you about your child's past health, your family's
health, and other issues.
Sometimes, when a child is found to have an enlarged lymph node
for no apparent reason, the doctor will watch the node closely to
see if it continues to grow. The doctor may prescribe antibiotics
if the gland is believed to be infected by bacteria. If the lymph
node remains enlarged, the next step is a
biopsy
(the removal and examination of tissue, cells, or fluids from the
body). Biopsies are also necessary for lymphomas that involve the
bone marrow or structures within the chest or abdomen.
Depending on the location of the tissue to be sampled, the
biopsy may be done using a thin hollow needle (known as needle
aspiration) or a small surgical incision made under local
anesthesia (the skin around the biopsy site will be numbed with
medication). Sometimes, a biopsy may require a larger surgical
incision under general
anesthesia
. This is the case in an
excisional biopsy
, where the entire enlarged lymph node or a chain of lymph nodes is
removed.
In the laboratory, tissue samples obtained from the biopsy are
examined to determine the specific type of lymphoma. In addition to
these basic lab tests, more sophisticated tests are also generally
done, including
genetic studies
, to distinguish between specific types of lymphoma.
To identify which areas of the body are affected by lymphoma,
the following tests are also commonly used:
- blood tests, including
complete blood count (CBC)
- blood chemistry, including tests of liver and kidney
function
- bone marrow biopsy or aspiration
-
lumbar puncture (spinal tap)
to check for cancer spread to the central nervous system (brain
and spinal cord)
- ultrasound
- computed tomography (CT) of the chest and abdomen or
sometimes X-rays
- magnetic resonance imaging (MRI)
- bone scan or gallium scan (when a radioactive material is
injected into the bloodstream to look for evidence of
inflammation or bone tumors)
- gallium scan to look for tumor or inflammatory cells
- Positron emisson tomography (PET) scan to look for abnormal
cells
These tests are important for determining the spread of the
lymphoma within the body and in deciding which type of treatment
should be used.
Treatment
Treatment of childhood lymphoma is largely determined by
staging
. Staging is a way to categorize or classify patients according to
how extensive the disease is at the time of diagnosis.
There are four stages of lymphoma, ranging from Stage I (cancer
involving only one area of lymph nodes or only one organ outside
the lymph nodes) to Stage IV (cancer has spread, or metastasized,
to one or more tissues or organs outside the lymphatic system). The
stage at diagnosis can guide medical professionals in the decision
of therapy and helps doctors predict how someone with lymphoma will
do in the long term.
Treatment may involve
radiation
(the use of high-energy rays to shrink tumors and keep cancer cells
from growing),
chemotherapy
(the use of highly potent medical drugs to kill cancer cells), or
both, depending on the type and stage of the cancer as well as the
age and overall health of the child.
Chemotherapy is the primary form of treatment for NHL, and is
generally important in treatment of Hodgkin disease, too. Children
with Stage I Hodgkin disease or NHL may be treated with radiation
alone, but for kids with more advanced stages of at the time of
diagnosis, chemotherapy is used, sometimes together with
radiation.
Short-Term and Long-Term Side Effects
Intensive lymphoma chemotherapy affects the bone marrow, causing
anemia
and bleeding problems, and increasing the risk for serious
infections. Chemotherapy treatments have side effects - some
short-term (such as hair loss, changes in skin color, increased
infection risk, and nausea and vomiting) and some long-term (such
heart and kidney damage, reproductive problems, or the development
of another cancer later in life) - that parents should discuss with
their doctor.
Side effects of radiation include fatigue, loss of appetite, and
skin reactions. When total-body irradiation is used prior to bone
marrow transplant, there is an increased risk that the child will
have slowed growth, thyroid problems, abnormal function of the
ovaries or testicles, or cataracts.
Chances for a Cure
The majority of kids with either Hodgkin disease or NHL are
cured, meaning they will have cancer-free survival for more than 5
years.
About 90% of children with Hodgkin disease go into
remission
(where there is no longer evidence of cancer cells in the body)
following initial chemotherapy. A long-term cure (5 years
disease-free or longer) is achieved in almost all Stage I or Stage
II patients, in up to 90% of Stage III patients, and more than 60%
of those with Stage IV.
In children with NHL, 5-year survival is about 90% for those
with Stage I or Stage II at the time of diagnosis, and close to 70%
for those with more advanced Stage III or IV disease.
New Treatments
Although most kids do recover from lymphoma, some with severe
disease will have a relapse (reoccurrence of the cancer) that
doesn't respond to conventional treatments. For these children,
bone marrow transplants and stem cell transplants are among the
newest treatment options.
During a bone marrow/stem cell transplant, intensive
chemotherapy with or without radiation therapy is given to kill
residual cancerous cells. Then, healthy bone marrow/stem
cells are introduced into the body in the hopes that it will
begin producing white blood cells that will help the child fight
infections.
Stem cell transplants use stem cells (primitive cells found
mainly in
umbilical cord blood
and bone marrow that are capable of developing into mature blood
cells) to boost the immune system after high doses of radiation and
chemotherapy.
Promising new treatments being developed for childhood lymphomas
include several different types of immune therapy, specifically the
use of antibodies to deliver chemotherapy medicines or radioactive
chemicals directly to lymphoma cells. This direct targeting of
lymphoma cells may prevent the toxic side effects that occur when
today's chemotherapy and radiation treatments damage normal,
noncancerous body tissues.
Reviewed by:
Donna Patton, MD
Date reviewed: June 2007
Originally reviewed by:
Robin E. Miller, MD
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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