Non-Hodgkin Lymphoma (NHL) is a type of cancer that affects the lymphatic system, usually found in the lymph nodes.
NHL is not a single disease but rather a group of several closely related cancers, called lymphoid neoplasms. The most recent 2016 revision of the World Health Organization classification of lymphoid neoplasms estimates that there are at least 86 types of NHL. Although the various types of NHL share many common characteristics, they differ in certain features, including their appearance under the microscope, their molecular features and growth patterns, their impact on the body, and how they respond to different types of treatment.
NHL is the seventh most common cancer affecting adults in the United States. The incidence of NHL in the United States nearly doubled between 1975 and 2013, and more than 72,000 new cases were estimated to be diagnosed in 2016.
Common signs and symptoms of NHL include swelling of the lymph nodes (which is often but not always painless), fever, night sweats, unexplained weight loss, and lack of energy.
It is important to note that most patients with these symptoms do not have lymphoma, as diseases or conditions not related to lymphoma may cause many of these symptoms. A good rule of thumb is to seek medical attention if any of the signs or symptoms last longer than two weeks, or sooner if the symptoms are severe enough to impact daily life.
Classifications of NHL
NHL is broadly categorized into two groups: B-cell lymphomas and natural killer (NK)/T-cell lymphomas. The three most common types of NHL in the U.S. are diffuse large B-cell lymphoma (22%), chronic lymphocytic leukemia/small lymphocytic lymphoma (18%), and follicular lymphoma (11%).
- B-cell lymphomas develop from abnormal B-cells and account for about 85 percent of all NHLs.
Natural killer (NK)/T-cell lymphomas
- NK/T-cell lymphomas develop from abnormal T-cells or NK cells and account for about 15 percent of all NHLs.
NHL types are also classified as either indolent (slow-growing) or aggressive (fast-growing).