Non-Hodgkin lymphoma is a catch-all label for more than 60 cancers
Non-Hodgkin lymphoma is defined by what it is not. The name covers every lymphoma except the Hodgkin kind: over 60 distinct cancers of white blood cells, some slow enough to watch for years, others fatal within months if untreated. Even specialists admit the label, on its own, tells a patient little.
Lymphomas arise from lymphocytes, a type of white blood cell. Typical signs are swollen lymph nodes, fever, night sweats, weight loss and fatigue, sometimes with bone pain, chest pain or itching. Where Hodgkin lymphoma tends to spread step by step between neighbouring nodes, the non-Hodgkin forms can appear in several parts of the body at once and follow no predictable route. Diagnosis relies on a biopsy of a lymph node or bone marrow, with scans used to stage the disease.
Because the group is so varied, its causes probably differ too. Weak immune function, autoimmune conditions and obesity raise the risk, and several infections are linked to particular subtypes: Epstein–Barr virus to Burkitt's lymphoma, the stomach bacterium Helicobacter pylori to gastric lymphoma, hepatitis C to certain spleen lymphomas. Chemicals such as PCBs and dioxins are also implicated, and even some metal or silicone implants are associated with one rare form. In 1987 the CDC counted certain types among AIDS-defining cancers, since the degree of immune suppression tracks closely with risk.
The name itself is a historical compromise. Doctors agreed quickly on how to classify Hodgkin lymphoma, leaving a large leftover group of very different diseases. Henry Rappaport's scheme of 1956 and 1966 was the first widely accepted way to sort them, and the Working Formulation, published in 1982, introduced the term non-Hodgkin lymphoma with three grades. The World Health Organization now splits lymphomas into five groups, four of them non-Hodgkin, yet cancer agencies still compile statistics under the old two-way division.
Treatment depends on how fast the disease grows and how widely it has spread, ranging from watchful waiting to chemotherapy, radiation, immunotherapy and stem-cell transplants; the most common chemotherapy for B-cell forms, R-CHOP, combines four drugs with the antibody rituximab. About 4.3 million people had the disease in 2015, and across all subtypes five-year survival is 71 to 74 percent. Diagnosis most often comes between 65 and 74.
Source: Non-Hodgkin lymphoma
