Lymphoma

Lymphoma occurs when the white blood cells (lymphocytes) in the lymphatic system grow abnormally. As disease progresses, it compromises your body's ability to fight infection and it may spread beyond the lymphatic system. The exact cause is unknown although it is likely that abnormal genes play a role in the development of all cancers.

Normally, your white blood cells go through a predictable life cycle. Old lymphocytes die, and your body creates new ones to replace them. With lymphoma, the new cells are abnormal and don't die when they should. They continue to multiply in a malignant process and as they accumulate within a lymph node they cause it to swell as a tumour.

Generally lymphoma starts in a group of nodes in one particular location but with time can spread to other lymph node groups and also to other parts of your lymphatic system including the lymphatic vessels, tonsils, adenoids, spleen, thymus and bone marrow where blood cells are made. Occasionally, lymphoma involves organs outside of the lymphatic system.

Treatment is determined by the type, grade and stage of the lymphoma (see below).

There are two main types of lymphoma: Hodgkin's Lymphoma and non-Hodgkin's Lymphoma (more than seven times as common, and there are 30 sub-types). They are considered separate because they behave slightly differently and are treated differently.

Lymphocytes exist either as B cells or T cells. B cells fight infection by producing specialized plasma cells, which in turn produce antibodies that neutralize foreign invaders. T cells are involved in killing foreign invaders directly. Hodgkin's lymphomas develop from abnormal B cells. Non-Hodgkin's lymphomas occur in B cells about 85 percent of the time. The rest arise in T cells.

In Hodgkin's lymphoma, B cells develop into large abnormal cancerous cells called Reed-Sternberg cells after the two pathologists who first discovered them. Instead of undergoing the normal cell cycle of life and death, these Reed-Sternberg cells don't die, and they continue to produce abnormal B cells in a malignant process. more on Hodgkin's...

Non-Hodgkin's lymphoma has been one of the most rapidly increasing types of cancer. There are more than 30 sub-types. The good news is that although the incidence has increased, so has the survival rate.

Symptoms

Often the only symptom of a lymphoma is having one or more enlarged lymph nodes in the body, often the neck. The swollen nodes are usually painless but they may become infected and present as a red, swollen and tender neck. Abdominal lymph nodes often cause pain in the belly or swelling. Enlarged lymph nodes in the chest cavity are common and may be seen on a chest XRay. Also, with time lymphomas may spread outside the lymph nodes to virtually any part of the body.

"Flu-like" symptoms such as lethargy, fever and sweats, and weight loss may occur before or after the appearance of lymph nodes.

Risk factors

In most cases, people diagnosed with lymphoma don't have any obvious risk factors, and many people who have risk factors for the disease never develop it. Some factors that may contribute to your risk of lymphoma include:

Age
Non-Hodgkin's lymphoma can occur at any age, but the risk increases with age. It's most common in people in their 60s.
Hodgkin's disease most commonly affects people between the ages of 15 and 40 and people older than age 55.

Family history
Anyone with a brother or a sister who has the Hodgkin's lymphoma disease faces an increased risk of developing the same disease, though this may be due to similar environmental exposures rather than genetic factors.

Compromised immune system
Having a compromised immune system, such as from HIV/AIDS or from having an organ transplant requiring medications to suppress your immune response, also appears to put you at a greater risk of lymphoma.

Infection
Having AIDS, in which your immune system is progressively weakened, places you at higher risk.

People who have had illnesses caused by the Epstein-Barr virus, such as infectious mononucleosis, may be four times as likely to develop Hodgkin's disease as people who haven't had a past Epstein-Barr infection.

An infection with the bacterium Helicobacter pylori, which is known to cause stomach ulcers, can cause an immune system response that raises your risk of non-Hodgkin's lymphoma, particularly in the stomach.

Chemicals
Certain chemicals, such as those used to kill insects and weeds, may increase your risk of developing lymphoma.

investigations

blood tests
Usually, having swollen lymph nodes means you're fighting an infection. Blood tests may rule out an infection (eg. toxoplasmosis, glandular fever) or other disease. The doctor will also want to look at the general blood count, and to check liver function.

needle biopsy
With an enlarged node the initial test is often a fine needle biopsy of the node. This is done as an outpatient and is usually only mildly uncomfortable. The results can take up to a week as the pathologist does many tests on the cells to determine their nature.

nodal excision
If the needle biopsy indicates a lymphoma is likely, the pathologist will request that the node be excised to get more information about the particular type (Hodgkin's vs non Hodgkin's) and grade of lymphoma. If the pathologist sees the classic large abnormal cells known as Reed-Sternberg cells the diagnosis of Hodgkin's Lymphoma is made. The lymphoma may be found to be growing slowly (low grade), growing at a moderate rate (intermediate grade) or growing rapidly (high grade). Knowing the type and grade will go a long way in determining which treatment is best.

CT scans
Scans of the neck, chest, abdomen and pelvis are necessary to determine the stage of the disease i.e. the extent of nodal involvement in the body and whether other organs such as the liver and spleen are involved.

PET scans
Overseas doctors are also increasingly using positron emission tomography (PET) scanning to detect cancer. For this test, a small amount of a radioactive tracer is injected into your body. This tracer is then absorbed by the tissues in your body. Tumors are typically more metabolically active than other tissues, so they absorb more of the tracer. True PET scanning is not yet available in New Zealand

Bone marrow sampling
Most cases will undergo sampling of the bone marrow of the hip (pelvis) to determine whether the malignant cells are present .

Classifying

Doctors classify non-Hodgkin's disease into about 30 types. Besides the differentiation between B cell and T cell types of the disease, classification is based on several other factors. These include:

Microscopic appearance- the "architecture" of the tissue
Cellular genetic changes
Cell size
Staining patterns with specific antibody stains
How the cancer cells group together
How fast the cancer grows

Staging

Staging basically describes how widely the tumors have spread and is therefore determined by the scan and bone marrow results. Lower staging means less disease and better cure rates.

Stage I: confined to one group of lymph nodes

Stage II: two separate groups of lymph nodes on one side of the diaphragm

Stage III: involvement of lymph nodes on both sides of the diaphragm

Stage IV: involvemt of other organs such as liver, spleen, bone marrow.

Treatment

As with other cancers, an earlier the diagnosis provides a greater chance for successful treatment. Treatment of lymphomas is directed by specialists in the field of medical oncology or haematology. Once the type, grade, and stage of lymphoma is known and after considering your age and general medical condition, the specialist will recommend a treatment according to a protocol established by the regional oncology centre (Auckland's is based at Auckland City Hospital). This treatment may be in the form of radiotherapy alone, chemotherapy alone, radiotherapy and chemotherapy, and in some cases where the lymphoma is expected to grow very slowly, observation and no treatment unless the tumour starts to cause problems.

Chemotherapy
Doctors use a combination of drugs — given orally or by injection — against fast-growing cancer cells. This treatment is used for intermediate-grade and high-grade lymphomas and advanced stages of the low-grade lymphomas. A single drug may be used if you have a low-grade type of the disease. Hodgkin's lymphomas respond to different drug combinations compared to non-Hodgkin's.

Radiation
High doses of radiation kill cancerous cells and shrink tumors. This treatment is for early stages of low-grade lymphomas. Sometimes, it's used along with chemotherapy on intermediate-grade tumors or to treat specific sites, such as the brain.

Stem-cell transplantation
Lymphomas tend to be sensitive to chemotherapy. However, if lymphoma recurs, higher doses of chemotherapy may be necessary to treat the disease. The amount of chemotherapy that can be given is limited because of the damage chemotherapy does to your bone marrow. In order to avoid this serious side effect, healthy stem cells (those capable of producing new cells) are taken from your blood or bone marrow and frozen. After you undergo very high doses of chemotherapy to kill the lymphoma, the healthy stem cells are thawed and injected back into your body. This treatment is used primarily to treat intermediate, or high-grade lymphomas that relapse after initial, successful treatment.

Observation
If your lymphoma appears to be slow growing, a wait and see approach may be an option. Slowly growing lymphomas with few symptoms may not require treatment for a year or more.

 

 

 

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