Lymphoma is cancer that begins in lymphocytes, a type of white blood cell made in the bone marrow and found in the blood and lymph tissue. Lymphoma occurs when something goes wrong inside the lymphocytes so they don’t mature and can’t carry out their normal immune functions defending against infection. They don’t die off like they should but instead collect in the lymph nodes.
What Is Non-Hodgkin’s Lymphoma?
There are two main types of lymphoma: Hodgkin’s lymphoma and non-Hodgkin’s lymphoma (NHL). The main difference between the two is the specific lymphocyte (white cell) involved. Hodgkin’s lymphoma involves abnormal B-cells called Reed-Sternberg cells. If Reed-Sternberg cells are not present, the lymphoma is classified as NHL.
NHL is one of the most common cancers in the United States. The American Cancer Society estimated that nearly 70,000 people—adults and children—would be diagnosed with NHL and about 19,000 would die from it in 2013.
The outlook for people with NHL depends on the type and stage of their disease and on the treatment they receive. Overall survival at five years is more than 60 percent, according to the National Cancer Institute.
NHL most often starts in the lymph nodes in the upper part of the body—in the neck or chest or under the arms. It can spread through the lymph system to other lymph nodes and outside the lymph nodes to the bone marrow, lungs, or liver.
The Lymph System
To understand lymphoma, it helps to have a basic knowledge of the lymph system. The lymph system is a network of tubes that slowly carries fluid from your tissues back into your bloodstream to be recycled. It has several parts.
- Lymph nodes, small bean-shaped organs that are part of the immune system and linked by lymphatic vessels. Lymph nodes store lymphocytes and act as filters to trap foreign particles. Lymph nodes are located throughout your body in your neck, underarms, and groin, and behind your knees. They are also deeper inside your body in your chest, abdomen, and pelvis.
- Lymphatic vessels, small tubes that carry lymph into your bloodstream.
- Lymph, fluid that circulates through the lymph system. It carries excess fluid and waste products from body tissues into the bloodstream. It also carries immune system cells.
- Lymph tissue, which includes lymph nodes and organs related to the immune and blood-forming systems, such as the spleen, thymus, and bone marrow.
Types of Lymphocytes
There are several types of lymphocytes.
- B lymphocytes, or B-cells. These make antibodies. Antibodies attach to bacteria and to cells infected with a virus or bacteria so that other immune cells recognize them and know to destroy them.
- T lymphocytes, or T-cells. There are many kinds of T-cells. They are involved in destroying invaders or tumor cells or in attracting or stimulating other immune cells to do this.
- Natural killer cells. These scout for cells that do not look normal and destroy them. There are about 60 types and subtypes of non-Hodgkin’s lymphoma. Correct identification is important in deciding which treatments are most likely to be effective.
There are about 60 types and subtypes of non-Hodgkin’s lymphoma. Correct identification is important in deciding which treatments are most likely to be effective.