The Lymphatic System
The lymphatic system is a system of thin tubes
that runs throughout the body. These tubes are
called lymph vessels or lymphatic vessels.
The lymphatic system is like the blood circulation the tubes (vessels) branch through all parts of the
body like the arteries and veins that carry blood.
But the lymphatic system tubes are much finer
and carry a colourless liquid called lymph.
Lymph is a clear fluid that circulates around
the body tissues. It contains a high number
of lymphocytes (white blood cells). Plasma
leaks out of the capillaries to surround and
bathe the body tissues. This then drains into
the lymph vessels.
The fluid, now called lymph, then flows
through the lymphatic system to the biggest
lymph vessel - the thoracic duct. The
thoracic duct then empties back into the
blood circulation.
You can probably feel some of your lymph
nodes. There are lymph nodes in many
parts of your body including
 Under your arms, in your armpits
 In each groin (at the top of your
legs)
 In your neck
There are also lymph nodes that you
cannot feel in
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Your abdomen
Your pelvis
Your chest
The lymphatic system includes other body
organs. These are the
 Spleen
 Thymus
 Tonsils
 Adenoids
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The spleen is under your ribs on the left side
of your body. The spleen has two main
different types of tissue, red pulp and white
pulp. The red pulp filters worn out and
damaged red blood cells from the blood and
recycles them. The white pulp contains many B lymphocytes and T lymphocytes. These are
white blood cells that are very important for fighting infection. As blood passes through the
spleen, these blood cells pick up on any sign of infection and begin to fight it.
The thymus is a small gland under your breast bone. The thymus helps to produce white blood
cells. It is usually most active in teenagers and shrinks in adulthood.
The tonsils are two glands in the back of
your throat. The adenoids are at the back
of your nose, where it meets the back of
your throat. The tonsils and adenoids (also
called the 'nasopharyngeal' tonsils) help to
protect the entrance to the digestive
system and the lungs from bacteria and
viruses.
What the lymphatic system does
The lymphatic system does several jobs in
the body. It
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Drains fluid back into the
bloodstream from the tissues
Filters lymph
Filters the blood
Fights infections
Draining fluid into the bloodstream
As the blood circulates, fluid leaks out from the blood vessels into the body tissues. This fluid is
important because it carries food to the cells and waste products back to the bloodstream. The leaked
fluid drains into the lymph vessels. It is carried through the lymph vessels to the base of the neck where
it is emptied back into the bloodstream. This circulation of fluid through the body goes on all the time.
Filtering lymph
The lymph nodes filter the lymph fluid as it passes through. White blood cells attack any bacteria or
viruses they find in the lymph as it flows through the lymph nodes. If cancer cells break away from a
tumour, they often become stuck in the nearest lymph nodes. This is why doctors check the lymph
nodes first when they are working out how far a cancer has grown or spread.
Filtering the blood
This is the job of the spleen. It filters the blood to take out all the old worn out red blood cells and then
destroys them. They are replaced by new red blood cells that are made in the bone marrow. The spleen
also filters out bacteria, viruses and other foreign particles found in the blood. White blood cells in the
spleen attack bacteria and viruses as they pass through.
Fighting infection
When people say "I'm not well, my glands are up" they are really saying they have swollen lymph nodes
because they have an infection. The lymphatic system helps fight infection in many ways such as
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Helping to make special white blood cells (lymphocytes) that produce antibodies
Having other blood cells called macrophages inside the lymph nodes which swallow up and kill any
foreign particles, for example germs
This function of the lymphatic system is really part of the immune system
Lymphatic Cancer (Lymphoma)
Lymphoma is a type of cancer that begins in immune system cells called lymphocytes. Like other
cancers, lymphoma occurs when lymphocytes are in a state of uncontrolled cell growth and
multiplication.
Lymphocytes are white blood cells that move throughout the body in a fluid called lymph. They are
transported by a network of vessels that make up the lymphatic system, part of the immune system. The
lymphatic system - whose job it is to fight infections or anything else that threatens the body - is also
comprised of lymph nodes that exist throughout the body to filter the lymph that flows through them.
The lymph nodes swell and tenderize when a large number of microbial organisms collect inside of
them, indicating local infection.
There are two primary types of lymphocytes: B cells and T cells. Both are designed to recognize and
destroy infections and abnormal cells. B cells produce proteins that travel throughout the body,
attaching themselves to infectious organisms and abnormal cells and alerting the immune system that
the pathogen needs to be destroyed. T cells actually kill the pathogens directly and serve a function in
regulating the immune system from over- or under-activity.
Lymphoma occurs when lymphocyte B or T cells transform and begin growing and multiplying
uncontrollably. Abnormal lymphocytes collect in one or more lymph nodes or in lymph tissues such as
the spleen or tonsils, and eventually they form a mass of cells called a tumor. Tumors grow and invade
the space of surrounding tissues and organs, depriving them of oxygen and nutrients.
If abnormal lymphocytes travel from one lymph node to the next or to other organs, the cancer can
spread or metastasize. Lymphoma development outside of lymphatic tissue is called extranodal disease.
How is lymphoma classified?
There are two types of lymphoma: Hodgkin lymphoma (HL, also called Hodgkin's disease) and nonHodgkin lymphoma (NHL). Both HL and NHL can occur in the same places and have similar symptoms.
Their differences are visible at a microscopic level.
Hodgkin lymphoma develops from a specific abnormal lineage of B cells. There are five subtypes of HL.
NHL may derive from either abnormal B or T cells, and its 30 subtypes are distinguished by unique
genetic markers. The large number of lymphoma subtypes has led to a complicated classification
scheme that involves microscopic appearance and well-defined genetic and molecular configurations.
What causes lymphoma?
Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body
follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and
when this process breaks down, cancer results. Scientists do not know exactly what causes lymphoma,
but they have identified several potential risk factors.
Genetics
Lymphoma can be the result of a genetic predisposition that is inherited from family members. It is
possible to be born with certain genetic mutations or a fault in a gene that makes one statistically more
likely to develop cancer later in life.
Carcinogens
Carcinogens are a class of substances that are directly responsible for damaging DNA, promoting or
aiding cancer. Exposure to certain pesticides, herbicides, and solvents such as benzene has been
associated with lymphoma. Similarly, black hair dye has been linked to higher rates of NHL. When our
bodies are exposed to carcinogens, free radicals are formed that try to steal electrons from other
molecules in the body. These free radicals damage cells, affecting their ability to function normally, and
the result can be cancerous growths.
Other medical factors
As we age, there is an increase in the number of possible cancer-causing mutations in our DNA. The risk
of NHL increases as we age, and HL is most common between ages 16-34 and 55 years and older.
Additional medical conditions that have been associated with higher lymphoma rates include infection
with HIV, human T-lymphocytic virus type 1 (HTLV-1), Epstein-Barr virus, Helicobacter pylori, or hepatitis
B or C; autoimmune disease (such as lupus); diseases that require therapies that suppress the immune
system; and any other immunodeficiency diseases.
In May 2012, researchers from the Department of Medicine at Stanford University identified the risk
factors that increased the likelihood of developing non-Hodgkin lymphoma early in life; they included
high fetal growth, being male, low birth order, and older maternal age.
What are the symptoms of lymphoma?
Cancer symptoms are quite varied and depend on where the cancer is located, where it has spread, and
how big the tumor is. Lymphoma usually first presents with swelling in the neck, underarm, or groin.
Additional swelling may occur where other lymph nodes are located such as in the spleen. In general,
enlarged lymph nodes can encroach on the space of blood vessels, nerves, or the stomach, leading to
swollen arms and legs, to tingling and numbness, or to feelings of being full, respectively.
Lymphoma symptoms also include nonspecific symptoms such as fever, chills, unexplained weight loss,
night sweats, lethargy, and itching.
How is lymphoma diagnosed and staged?
In order to diagnose lymphoma, physicians will request a complete physical exam as well as personal
and family medical histories. An oncologist (cancer specialist) will usually be consulted to review the
results of several tests.
Blood tests will be used to test blood cell, kidney, and liver performance. They can also detect a
chemical called lactase hydrogenase (LDH), of which high levels have been associated with an aggressive
form of NHL.
Several imaging techniques are employed in order to see if cancer exists and to find out how far they
have spread. Common imaging tests include:
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X-rays
Computerized tomography (CT) scans
Magnetic resonance imaging (MRI)
Lymphangiogram
Gallium scan
Positron emission tomography (PET) scans
Physicians may also perform bone marrow examinations to see if the lymphoma has infected the bone
marrow. Bone marrow samples are often taken from the hip and examined for the presence of
abnormal B or T cells.
The only absolute way to make a cancer diagnosis is to remove a small sample of the tumor and look at
it under the microscope in a procedure called a biopsy. Doctors may gather the sample by inserting a
needle through the skin, surgical methods, or laparoscopic methods. A pathologist examines the sample
under a microscope to determine if cancer exists.
After a diagnosis is made, doctors analyze the tissue samples and test results to find out how far the
cancer has spread and to determine the stage of the cancer. The stage lets oncologists know which
choices will be available for treatment and it informs prognoses.
A common and simple classification scheme for Hodgkin's lymphoma considers it to be bulky (large
tumor, worse prognosis) or nonbulky (small tumor, better prognosis). Non-Hodgkin's lymphoma is
classified according to its microscopic appearance, location in the body, and genetic and molecular
features. It is frequently divided into three grades. Low grade, or indolent, lymphomas grow slowly and
often do not require immediate treatment. Intermediate grade lymphomas are rapidly growing and
require immediate treatment. They are often curable. High grade lymphomas are aggressive and rapidly
growing, require intesive and immediate treatment, and are often uncurable.
HL and NHL use a similar staging system to describe the extent of the disease.
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Stage I or early disease is when lymphoma is found in a single lymph node region or in a single organ
outside the lymph node.
Stage II or locally advanced disease is when two or more lymph node regions on the same side of the
diaphragm or one lymph node region and a nearby tissue or organ carries lymphoma.
Stage III or advanced disease is when two or more lymph nodes or a lymph node and an organ on the
opposite side of the body are affected by lymphoma.
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Stage IV or widespread, disseminated disease is when the lymphoma has spread to the spleen, bone
marrow, bone, or central nervous system.
Both types of lymphoma may also receive an A classification to indicate no symptoms like fever and
weight loss, a B classification to indiciate such symptoms, or an E classification to indicate that the tumor
has spread directly from a lymph node to an organ.
How is lymphoma treated?
Cancer treatment depends on the type of cancer, the stage of the cancer (how much it has spread), age,
health status, whether or not one has received previous cancer treatment, and additional personal
characteristics. Lymphoma treatment is usually designed to result in complete remission of the disease a state where there may be lymphoma cells in the body, but they are undetectable and cause no
symptoms. Common lymphoma treatments include chemotherapy, radiation therapy, and biological
therapy.
The ultimate goal of lymphoma treatment is durable remission, or remission that lasts a long time. If the
cancer comes back, this is called recurrence. After therapy the patient may see improvement
(lymphoma shrinks), a stable disease (lymphoma is the same size), progression (lymphoma worsens), or
a refractory disease (the lymphoma resists treatment). Patients may also undergo induction therapy
that is designed to induce remission, salvage therapy that is designed to take over for a failing
treatment, or maintenance therapy that is treatment meant to prevent recurrence.
Chemotherapy
Chemotherapy utilizes chemicals that interfere with the cell division process - damaging proteins or DNA
- so that cancer cells will commit suicide. These treatments target any rapidly dividing cells (not
necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage
while cancer cells cannot. Chemotherapy is generally used to treat cancer that has spread or
metastasized because the medicines travel throughout the entire body. Treatment occurs in cycles so
the body has time to heal between doses. However, there are still common side effects such as hair loss,
nausea, fatigue, and vomiting. Combination therapies often include multiple types of chemotherapy or
chemotherapy combined with other treatment options.
Radiation
Radiation treatment, also known as radiotherapy, destroys cancer by focusing high-energy rays on the
cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to
commit suicide. Radiotherapy utilizes high-energy gamma-rays that are emitted from metals such as
radium or high-energy x-rays that are created in a special machine. Radiotherapy can be used as a
standalone treatment to shrink a tumor or destroy cancer cells, and it is also used in combination with
other cancer treatments.
Side effects of radiation therapy may include mild skin changes resembling sunburn or suntan, nausea,
vomiting, diarrhea, and fatigue. Patients also tend to lose their appetites and have trouble maintaining
weight, but most side effects subside a few weeks after completing treatment.
Chemical R848 combined with radiotherapy increases a lymphoma patient's chance for long-time
survival fourfold, compared to radiotherapy alone, scientists from the University of Manchester,
England, reported in the journal Blood in October 2012. Chemical R848 sends signals to the receptors
which are on the outside part of immune cells, triggering them into action.
How can lymphoma be prevented?
There are no known ways to prevent lymphoma. However, physicians recommend avoiding known risk
factors and avoiding viral infections or conditions that suppress the immune system.