Lymphoma occurs in two main types, Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Lymphoma is a cancer that starts in white blood cells (lymphocytes) within the body’s immune (lymph or lymphatic) system. The lymph system helps fight infections and some other diseases, and also helps control the flow of body fluids. HL can often be cured, while the prognosis of NHL depends on the specific type. Both HL and NHL are more common in adults, but they can also occur in children and teens. NHL tends to occur in younger children, while HL more commonly affects older children and teens.
Forms of lymphomas
Hodgkin lymphoma usually starts in B-cell lymphocytes, which make proteins called antibodies to help protect the body from bacteria and viruses. HL can start almost anywhere in the body, but the most common sites are lymph nodes in the chest, neck, or under the arms.
Non-Hodgkin lymphoma (NHL) also usually starts in B-cell lymphocytes. Types of NHL include indolent lymphomas (most commonly follicular lymphoma), which grow and spread slowly; and aggressive lymphomas (most commonly diffuse large B cell lymphoma, or DLBCL), which grow and spread quickly. Some indolent lymphomas can be monitored rather than treated right away, while aggressive lymphomas need immediate treatment. Some types of lymphoma, like mantle cell lymphoma, don’t fit neatly into either category. All types of NHL can spread to other parts of the body (such as the liver, brain, or bone marrow) if not treated.
Lymphoma of the skin includes numerous types that can start in either B-cell or T-cell lymphocytes and are called cutaneous B-cell lymphomas (CBCLs) and cutaneous T-cell lymphomas (CTCLs), respectively. Most skin lymphomas are T-cell lymphomas. Lymphomas of the skin are uncommon, accounting for only about 4 percent of all non-Hodgkin lymphomas.
Waldenstrom Macroglobulinemia (WM) starts in B-cell lymphocytes and is also called lymphoplasmacytic lymphoma. WM cells grow mainly in bone marrow, crowding out normal cells. This type of lymphoma is rare, occurring in only about 3 cases per million people per year in the United States.
Primary CNS lymphoma starts in the brain and can spread to the spinal fluid and eyes. It is a rare and highly aggressive form of NHL.
Risk factors for lymphomas
Age — Getting older is a strong risk factor for lymphoma overall, and most cases occur in people age 60 or older. But some types of lymphoma are more common in younger people. Diagnoses of Hodgkin lymphoma (HL) usually occur in one’s 20s and after age 55.
Gender — HL and non-Hodgkin lymphoma (NHL) occur slightly more often in men than in women, but some types of NHL are more common in women.
Family History — Siblings of young people with HL are at higher risk for the disease, and the risk is very high for an identical twin of a person with HL. However, most people with HL do not have a family history of it. Having a first-degree relative (parent, child, sibling) with NHL increases the risk of developing NHL.
Race — In the United States, whites are more likely than African Americans and Asian Americans to develop NHL, while African-Americans are more likely than whites to develop lymphoma of the skin.
Exposure to certain chemicals or drugs — Research is still ongoing, but chemicals posing potential risk for developing NHL include herbicides and insecticides, some chemotherapy drugs (patients who have been treated for HL have an increased risk of later developing NHL), and some drugs used to treat rheumatoid arthritis.
Radiation Exposure — Patients treated with radiation therapy for cancers, such as HL, have a slightly increased risk of developing NHL later in life. This risk is greater for patients treated with both radiation therapy and chemotherapy.
Certain Infections — Lymphoma risk increases as a result of infections that directly transform lymphocytes (like the Epstein-Barr virus), weaken the immune system (like HIV), and cause chronic immune stimulation (like Hepatitis C).
Body Weight & Diet — Some studies suggest that being overweight or obese may increase the risk of NHL. Other studies have suggested that a diet high in fat and meats may raise your risk. More research is needed.
Breast Implants — Some women with implants (especially those with textured rather than smooth surfaces) develop a type of anaplastic large cell lymphoma (ALCL) in their breast, although this is rare.
Symptoms of lymphomas
Enlarged lymph nodes. These can occur in different parts of the body for both Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). The most common symptom of HL is a lump in the neck, under the arm, or in the groin. It doesn’t usually hurt, but it may become painful after drinking alcohol. The lump might get bigger over time, or new lumps might appear near it or in other parts of the body.
Swollen abdomen (belly). Lymphomas that start or grow in the abdomen can cause swelling or pain. The cause can be lymph nodes or organs such as the spleen or liver enlarging, and/or the build-up of large amounts of fluid. Lymphomas in the stomach or intestines can cause abdominal pain, nausea, or vomiting.
Appetite loss. An enlarged spleen might press on the stomach, which can cause appetite loss and a feeling of fullness after only a small meal.
Chest pain or pressure/trouble breathing. When lymphoma starts in the thymus or lymph nodes in the chest, it may press on the nearby trachea (windpipe), which can cause coughing, trouble breathing, or a feeling of chest pain or pressure. Swollen lymph nodes could also press on a vein — the superior vena cava — that carries blood to the heart. This can lead to swelling (and sometimes a bluish-red color) in the head, arms, and upper chest and is life-threatening.
Changes in thinking, mood, movement, and perception. Lymphomas of the brain can cause headache, trouble thinking, weakness in parts of the body, personality changes, and sometimes seizures. Other types of lymphoma can spread to the area around the brain and spinal cord and can cause problems such as double vision, facial numbness, and trouble speaking.
Skin lesions. Lymphomas of the skin can appear as papules (small, pimple-like lesions), patches (flat lesions), plaques (thick, raised or lowered lesions), or nodules or tumors (larger lumps or bumps under the skin). The lesions are often itchy, scaly, and red to purple, and more than one type can appear at the same time. Some skin lymphomas appear as a rash over some or most of the body (known as erythroderma). Sometimes larger lesions can break open (ulcerate).
Other symptoms can include
Fever (which can come and go over several weeks) without an infection)
Severe or frequent infections
Drenching night sweats
Unexplained weight loss (at least 10 percent of your body weight over 6 months)
Easy bruising or bleeding
How are lymphomas treated with radiation?
People with Hodgkin lymphoma (HL) can receive involved site radiation therapy (ISRT), which focuses only on the lymph nodes that originally contained lymphoma and any nearby locations the cancer reached. This shrinks the size of the treatment area. ISRT is replacing involved field radiation therapy (IFRT). IFRT affects a larger treatment area, which could increase the risk to nearby normal tissues and organs.
Radiation can be used as the main treatment for some types of non-Hodgkin lymphoma (NHL) if they are found early.
Radiation is sometimes used along with chemotherapy for more advanced or more aggressive lymphomas.
People receiving a stem cell transplant may get radiation to the whole body along with high-dose chemotherapy, to try to kill lymphoma cells throughout the body.
Radiation can be used as part of palliative care, to ease symptoms caused by lymphoma that has spread to internal organs, or when a tumor causes pain by pressing on nerves. It may be used as a form of urgent treatment in children with symptoms caused by large tumors in the chest.
Lymphoma of the skin can be treated with electron beam radiation, which penetrates only as far as the skin. Some thicker lesions are treated with high energy radiation, which penetrates deeper into the body.
Radiation is rarely used to treat Waldenstrom macroglobulinemia (WM). It is used to shrink an enlarged spleen or lymph nodes if they are causing symptoms.
More extensive information about lymphomas and other cancers may be found at these sites:
American Cancer Society: Cancer.org
American Society of Clinical Oncology: Cancer.net
National Cancer Institute: Cancer.gov