A tumor of the lymphoid tissue. The major types of lymphoma are Hodgkin’s disease and non-Hodgkin’s lymphoma (NHL). NHL can in turn be divided into low-grade, intermediate-grade, high-grade, and miscellaneous lymphomas. The course of NHL varies greatly, from indolent to rapidly fatal. Treatment options include chemo and radiation therapy.
For most cancers, researchers are still trying to understand how they are caused. The same is true for lymphoma – doctors do not know what causes it, although it is more likely to occur in certain people.
Medical researchers have identified certain risk factors that make lymphoma more likely, although they often do not understand why:
- Age – most non-Hodgkin lymphomas are in people 60 years of age and over
- Sex – there are different rates of different types of non-Hodgkin’s lymphoma across the sexes
- Ethnicity and location – in the US, African-Americans and Asian-Americans are less prone than white Americans, and the disease is more common in developed nations of the world
- Chemicals and radiation – some chemicals used in agriculture have been linked, as has nuclear radiation exposure
- Immune deficiency – for example, caused by HIV infection or in organ transplantation
Autoimmune disease, in which the immune system attacks the body’s own cells
- Infection – certain viral and bacterial infections increase the risk. The Helicobacter Infection has been implicated, as has the Epstein Barr Virus (the virus that causes glandular fever)
- Infectious mononucleosis – infection with Epstein-Barr virus
- Age – two specific groups are most affected: typically people in their 20s, and people over the age of 55 years
- Sex – slightly more common in men
- Location – most common in the US, Canada and northern Europe; least common in Asia
- Family – if a sibling has the condition, the risk is slightly higher, and very high if there is an identical twin
- Affluence – people from higher socioeconomic status are at greater risk
- HIV infection
NHLs are tumors originating from lymphoid tissues, mainly of lymph nodes. Various neoplastic tumor cell lines correspond to each of the cellular components of antigen-stimulated lymphoid follicles.
NHL represents a progressive clonal expansion of B cells or T cells and/or NK cells arising from an accumulation of lesions affecting proto-oncogenes or tumor suppressor genes, resulting in cell immortalization. These oncogenes can be activated by chromosomal translocations (ie, the genetic hallmark of lymphoid malignancies), or tumor suppressor loci can be inactivated by chromosomal deletion or mutation. In addition, the genome of certain lymphoma subtypes can be altered with the introduction of exogenous genes by various oncogenic viruses. Several cytogenetic lesions are associated with specific NHLs, reflecting the presence of specific markers of diagnostic significance in subclassifying various NHL subtypes.
Almost 85% of NHLs are of B-cell origin; only 15% are derived from T/NK cells, and the small remainder stem from macrophages. These tumors are characterized by the level of differentiation, the size of the cell of origin, the origin cell’s rate of proliferation, and the histologic pattern of growth.
For many of the B-cell NHL subtypes, the pattern of growth and cell size may be important determinants of tumor aggressiveness. Tumors that grow in a nodular pattern, which vaguely recapitulate normal B-cell lymphoid follicular structures, are generally less aggressive than lymphomas that proliferate in a diffuse pattern. Lymphomas of small lymphocytes generally have a more indolent course than those of large lymphocytes, which may have intermediate-grade or high-grade aggressiveness. However, some subtypes of high-grade lymphomas are characterized by small cell morphology.
- Swelling in the legs or ankles
- Cramping and bloating of the abdomen
- Night sweats and fever
- Weight loss and loss of appetite
- Unusual itching
- Pain or altered sensation
- Loss of appetite
- Unusual tiredness/lack of energy
- Persistent coughing
- Enlarged tonsils
The common tests for lymphoma are described in this chapter. You may not have all the tests. When the tests are done, your doctor or doctors will tell you what they have learned about your cancer, and suggest the best treatment for you.
Your doctor will begin by examining your body, especially the areas where there are lymph nodes. Your doctor will also discuss your medical history and ask about symptoms.
If you have swollen lymph nodes that your doctor thinks may be cancerous, they will take some tissue from a swollen lymph node. This is called a tissue biopsy. The whole node may be removed or only a part of the node. This tissue will be sent to a pathology laboratory to be examined in detail to see if it has cancer cells in it.
You could have either a general or a local anaesthetic when you have your biopsy. This will depend on where the lymph node is that the doctor wishes to biopsy. If the biopsy shows that you have lymphoma, other tests will be done to find out whether the cancer has spread, and if so, to where. This is called ‘staging’ the cancer.
Your doctor may take some blood from your arm using a needle and syringe. This will be sent to a pathology laboratory to be examined. These tests will also tell the doctors how well your other organs such as liver and kidneys are working.
Bone marrow biopsy
Lymphoma cells can spread to bone marrow. In a bone marrow biopsy, a sample from your bone marrow is taken with a needle. The bone marrow is usually taken from the back of your hipbone.
You will have a local anaesthetic and possibly some sedative so you do not feel pain during the biopsy. The sample will be looked at under a microscope to see if the lymphoma has spread to the bone marrow.
Computerised tomography (CT) scan
A CT scan is a special type of x-ray that gives a three-dimensional (3-D) picture of the organs and other structures in your body. It usually takes about 30 to 40 minutes to complete this painless test.
You will be asked to lie on a table while the CT scanner, which is large and round like a doughnut, moves around you. Before the scan, you may have an injection of a dye that shows up body tissues more clearly. You will be asked not to eat or drink for a while before you have your scan. Most people are able to go home as soon as their scan is over.
A child with a non-Hodgkin lymphoma will also have an ultrasound scan of their abdomen.
In this test your whole body is checked. You will have an injection of radioactive gallium, a sort of metal. After a few days, when it has had time to circulate around your body, you will return to the hospital to have pictures of your body taken with a special camera (a gamma camera). If gallium is seen outside body areas that normally would take it up, a cancer may be present at that site.
Positron emission tomography (PET) scan
A PET scan builds up clear and detailed pictures of the body. You will have an injection of a glucose solution containing a very small amount of a radioactive substance. The scanner can ‘see’ this substance, which shows where the glucose is being used in the body. Cancer cells show up as areas where glucose is being used by actively growing cells.
Sometimes, other tests are needed. These could include:
Magnetic resonance imaging (MRI), which uses a combination of magnetism and radio waves to build up detailed cross-section pictures (or images) of part of the body.
Ultrasound scan, where sound waves of a very high frequency are directed at the body. The sound waves are reflected back differently by different types of tissue. These differences are measured and used to build up pictures of structures inside the body.
Lumbar puncture, where a needle is put into the area around the spinal cord and fluid taken for examination under a microscope.
Gastroscopy, in which a long, hollow tube with a light attached is inserted down the throat and into the stomach. It projects magnified pictures of the inside of the stomach, and instruments can be inserted through the tube, if needed.
Colonoscopy, where a long, slim, flexible tube, with a light attached, is inserted through the anus, so the doctor can examine the bowel.
If any of these are required, your doctor should explain to you why you need the test and what is involved.
Which treatment options are appropriate for your Hodgkin’s lymphoma depends on your type and stage of disease, your overall health, and your preferences. The goal of treatment is to destroy as many cancer cells as possible and bring the disease into remission.
Chemotherapy is a drug treatment that uses chemicals to kill lymphoma cells. Chemotherapy drugs travel through your bloodstream and can reach nearly all areas of your body.
Chemotherapy is often combined with radiation therapy in people with early-stage classical type Hodgkin’s lymphoma. Radiation therapy is typically done after chemotherapy. In advanced Hodgkin’s lymphoma, chemotherapy may be used alone or combined with radiation therapy.
Chemotherapy drugs can be taken in pill form, through a vein in your arm or sometimes both methods of administration are used. Several combinations of chemotherapy drugs are used to treat Hodgkin’s lymphoma.
Side effects of chemotherapy depend on the specific drugs you’re given. Common side effects include nausea and hair loss. Serious long-term complications can occur, such as heart damage, lung damage, fertility problems and other cancers, such as leukemia.
Radiation therapy uses high-energy beams, such as X-rays, to kill cancer cells. For classical Hodgkin’s lymphoma, radiation therapy can be used alone, but it is often used after chemotherapy. People with early-stage lymphocyte-predominant Hodgkin’s lymphoma typically undergo radiation therapy alone.
During radiation therapy, you lie on a table and a large machine moves around you, directing the energy beams to specific points on your body. Radiation can be aimed at affected lymph nodes and the nearby area of nodes where the disease might progress. The length of radiation treatment varies, depending on the stage of the disease.
Radiation therapy can cause skin redness and hair loss at the site where the radiation is aimed. Many people experience fatigue during radiation therapy. More-serious risks include heart disease, stroke, thyroid problems, infertility and other forms of cancer, such as breast or lung cancer.
Stem cell transplant
A stem cell transplant is a treatment to replace your diseased bone marrow with healthy stem cells that help you grow new bone marrow. A stem cell transplant may be an option if Hodgkin’s lymphoma returns despite treatment.
During a stem cell transplant, your own blood stem cells are removed, frozen and stored for later use. Next you receive high-dose chemotherapy and radiation therapy to destroy cancerous cells in your body. Finally your stem cells are thawed and injected into your body through your veins. The stem cells help build healthy bone marrow.