Types, Stages & Risk Factors

Types

Non-Hodgkin’s lymphoma is divided into types and subtypes based on the specific type of cell affected, the level of maturity reached by the cells, their appearance under a microscope or the way they grow. There are at least 10 different types of non-Hodgkin’s lymphomas. The type and subtype matter because they sometimes help doctors decide which treatments are most likely to be effective.

Most non-Hodgkin’s lymphomas—about 85 percent—begin in the B cells. There are several subtypes of B-cell lymphomas, like diffuse large B-cell lymphoma, follicular lymphoma and small lymphocytic lymphoma.

Less than 15 percent of non-Hodgkin’s lymphomas begin in the T cells. In some of these, natural killer cells are also involved. These are called T/NK-cell lymphomas.

Non-Hodgkin’s lymphoma is divided into two main subcategories:

• Indolent non-Hodgkin’s lymphoma, which tends to grow slowly and cause fewer symptoms
• Aggressive non-Hodgkin’s lymphoma, which tends to grow and spread quickly and cause severe symptoms

Doctors may also specify whether your lymphoma is contiguous (lymph nodes affected by cancer are next to each other) or noncontiguous (lymph nodes affected by cancer are not next to each other but are on the same side of the diaphragm, the muscle that divides the chest from the abdomen).

Stages

Staging refers to the way doctors classify lymphoma based on where it is in the body. People who have lymphoma are considered to be at one of these stages:

• Stage I: This stage applies to those who have lymphoma in only one lymph-node area or one organ.
• Stage II: This stage applies to those who have lymphoma in two or three lymph-node areas near each other, such as all in the neck and chest.
• Stage III: This stage applies to those who have lymphoma in several lymph-node areas in the neck, chest and abdomen.
• Stage IV: This stage applies to those who have widespread lymphoma in their lymph nodes and other organs, such as the bone marrow, lungs and liver.

Doctors may add a letter after your stage to describe more about your disease. In non-Hodgkin’s lymphoma, doctors use the letter E (such as “stage IIIE”) to mean that your cancer is extranodal (goes beyond your lymph nodes).

Risk Factors

Doctors do not know what causes non-Hodgkin’s lymphoma. There are several factors that may increase risk. Keep in mind that most people who get the disease have none of the risk factors. And most people with the risk factors do not develop the disease.

Non-Hodgkin’s lymphoma is more common in men than in women, and the risk increases with age. Also, you may be at higher risk for non-Hodgkin’s lymphoma if any of these is true:

• Your immune system is weakened by an inherited disease, autoimmune disease, human immunodeficiency virus (HIV) or drugs given because you had an organ transplant.
• You have been infected with human T-lymphotropic virus type I (HTLV-1), Epstein-Barr virus (which causes mononucleosis), Helicobacter pylori (a bacteria that causes ulcers) or hepatitis C.
• You were exposed to certain chemicals, such as ingredients in pesticides, herbicides, solvents or fertilizers.