Non-hodgkin Lymphoma

What Is Non-Hodgkin Lymphoma?

Cancer starts when cells begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas.

Non-Hodgkin lymphoma (also known as non-Hodgkin’s lymphoma, NHL, or sometimes just lymphoma) is a cancer that starts in white blood cells called lymphocytes, which are part of the body’s immune system.

• NHL is a term that’s used for many different types of lymphoma that all share some of the same characteristics. There is another main type of lymphoma, called Hodgkin lymphoma, which is treated differently.
• NHL most often affects adults, but children can get it too.
• NHL usually starts in lymph nodes or other lymph tissue, but it can sometimes affect the skin.

Where lymphoma starts

Lymphoma affects the body’s lymph system (also known as the lymphatic system). The lymph system is part of the immune system, which helps fight infections and some other diseases. It also helps fluids move through the body.

Lymphomas can start anywhere in the body where lymph tissue is found. The major sites of lymph tissue are:

• Lymph nodes: Lymph nodes are bean-sized collections of lymphocytes and other immune system cells throughout the body, including inside the chest, abdomen, and pelvis. They are connected by a system of lymphatic vessels.
• Spleen: The spleen is an organ under the lower ribs on the left side of the body. The spleen makes lymphocytes and other immune system cells. It also stores healthy blood cells and filters out damaged blood cells, bacteria, and cell waste.
• Bone marrow: The bone marrow is the spongy tissue inside certain bones. This is where new blood cells (including some lymphocytes) are made.
• Thymus: The thymus is a small organ behind the upper part of the breastbone and in front of the heart. It’s important in the development of T lymphocytes.
• Adenoids and tonsils: : These are collections of lymph tissue in the back of the throat. They help make antibodies against germs that are breathed in or swallowed.
• The stomach, intestines, and many other organs also have lymph tissue.

Types of non-Hodgkin lymphoma

Treatment for NHL depends on which type it is, so it’s important for doctors to find out the exact type of lymphoma you have. The type of lymphoma depends on what type of lymphocyte is affected (B cells or T cells), how mature the cells are when they become cancerous, and other factors.

B-cell vs T-cell lymphomas

The lymph system is made up mainly of lymphocytes, a type of white blood cell that helps the body fight infections. There are 2 main types of lymphocytes:

• B lymphocytes (B cells): B cells normally help protect the body against germs (bacteria or viruses) by making proteins called antibodies. The antibodies attach to the germs, marking them for destruction by other parts of the immune system.
• T lymphocytes (T cells): There are several types of T cells. Some T cells destroy germs or abnormal cells in the body. Other T cells help boost or slow the activity of other immune system cells.

Lymphoma can start in either type of lymphocytes, but B-cell lymphomas are most common.

Indolent vs. aggressive lymphomas

Types of NHL can also be grouped based on how fast they grow and spread:

• Indolent lymphomas grow and spread slowly Some indolent lymphomas might not need to be treated right away, but can be watched closely instead. The most common type of indolent lymphoma in the United States is follicular lymphoma.
• Aggressive lymphomas grow and spread quickly, and usually need to be treated right away. The most common type of aggressive lymphoma in the United States is diffuse large B cell lymphoma (DLBCL).
• Some types of lymphoma, like mantle cell lymphoma, don’t fit neatly into either of these categories.

Regardless of how quickly they grow, all non-Hodgkin lymphomas can spread to other parts of the lymph system if not treated. Eventually, they can also spread to other parts of the body, such as the liver, brain, or bone marrow.

Classifying types of NHL

There are many different types of non-Hodgkin lymphoma (NHL), so classifying it can be quite confusing (even for doctors). Several different systems have been used, but the most recent system is the World Health Organization (WHO) classification. The WHO system groups lymphomas based on:

• The type of lymphocyte the lymphoma starts in
• How the lymphoma looks under a microscope
• The chromosome features of the lymphoma cells
• The presence of certain proteins on the surface of the cancer cells

Tests for Non-Hodgkin Lymphoma

Most people with non-Hodgkin lymphoma (NHL) see their doctor because they have felt a lump that hasn’t gone away, they develop some of the other symptoms of NHL, or they just don’t feel well and go in for a check-up.

If you have signs or symptoms that suggest you might have lymphoma, exams and tests will be done to find out for sure and, if so, to determine the exact type of lymphoma.

Medical history and physical exam

Biopsy

For a biopsy, a small piece of a lymph node or, more often, an entire lymph node is removed for testing in a lab.

Biopsies to diagnose non-Hodgkin lymphoma

There are several types of biopsies. Doctors choose which one to use based on each person’s situation.

Excisional or incisional biopsy: This is the preferred and most common type of biopsy if lymphoma is suspected, because it almost always provides enough of a sample to diagnose the exact type of NHL.

In this procedure, a surgeon cuts through the skin to remove the lymph node.

Needle biopsy: Needle biopsies are less invasive than excisional or incisional biopsies, but the drawback is that they might not remove enough of a sample to diagnose lymphoma (or to determine which type it is). There are 2 main types of needle biopsies:

• • In a fine needle aspiration (FNA) biopsy, the doctor uses a very thin, hollow needle attached to a syringe to withdraw (aspirate) a small amount of tissue from an enlarged lymph node or a tumor mass.
  • For a core needle biopsy, the doctor uses a larger needle to remove a slightly larger piece of tissue.

If lymphoma has already been diagnosed, needle biopsies are sometimes used to check abnormal areas in other parts of the body that might be from the lymphoma spreading or coming back after treatment.

Other types of biopsies

These procedures are not normally done to diagnose lymphoma, but they might be used to help determine the stage (extent) of a lymphoma that has already been diagnosed.

Bone marrow aspiration and biopsy
Lumbar puncture (spinal tap)
Pleural or peritoneal fluid sampling:
Lab tests on biopsy samples

All biopsy samples and fluids are looked at in the lab by a pathologist (a doctor specially trained to recognize cancer cells). The size and shape of the cells and how they are arranged may show not only if the person has a lymphoma, but also what type of lymphoma it is. But usually other types of lab tests are needed as well.

Flow cytometry and immunohistochemistry

Chromosome tests

Cytogenetics: In this lab test, the cells are checked for any abnormalities in the chromosomes.

• Fluorescent in situ hybridization (FISH)
• Polymerase chain reaction (PCR)

Imaging tests

Chest x-ray
Computed tomography (CT) scan
CT-guided needle biopsy
Magnetic resonance imaging (MRI) scan
Ultrasound
Positron Emission Tomography (PET) Scan

For a PET scan, you are injected with a slightly radioactive form of sugar, which collects mainly in cancer cells. A special camera is then used to create a picture of areas of radioactivity in the body. The picture is not detailed like a CT or MRI scan, but it can provide helpful information about your whole body.

If you have lymphoma, a PET scan might be done to:

• See if an enlarged lymph node contains lymphoma.
• Find small areas that might be lymphoma, even if the area looks normal on a CT scan.
• Check if a lymphoma is responding to treatment. Some doctors will repeat the PET scan after 1 or 2 courses of chemotherapy. If the chemotherapy is working, the lymph nodes will no longer absorb the radioactive sugar.
• Help decide whether an enlarged lymph node still contains lymphoma or is just scar tissue after treatment.

Other tests

Blood tests

Blood tests are not used to diagnose lymphoma, but they can sometimes help determine how advanced the lymphoma is.

• A complete blood count (CBC) measures the levels of different cells in the blood. For a person already known to have lymphoma, low blood cell counts might mean that the lymphoma is growing in the bone marrow and affecting new blood cell formation.
• Blood chemistry tests are often done to look at how well the kidney and liver function are working.
• If lymphoma has been diagnosed, the lactate dehydrogenase (LDH) level may be checked. LDH levels are often increased in patients with lymphomas.
• For some types of lymphoma or if certain treatments might be used, your doctor may also advise you to have tests to see if you’ve been infected with certain viruses, such as hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV). Infections with these viruses may affect your treatment.

Tests of heart and lung function

These tests are not used to diagnose lymphoma, but they might be done if you are going to get certain chemotherapy drugs commonly used to treat lymphoma that could affect the heart or the lungs.

• Your heart function may be checked with an echocardiogram (an ultrasound of the heart) or a MUGA scan.
• Your lung function may be checked with pulmonary function tests, in which you breathe into a tube connected to a machine.

Treatment options for Lymphoma:

• Chemotherapy
• Immunotherapy
• Targeted Drug Therapy for Non-Hodgkin Lymphoma
• Radiation Therapy
• Radioimmunotherapy
• High-Dose Chemotherapy and Stem Cell Transplant
• Surgery (very rarely)