This varies in its malignancy depending on the nature and activity of the abnormal lymph cells. The disease is hard to classify histologically, so various classification systems have been evolved. High- and low-grade categories are recognised according to the rate of proliferation of abnormal lymph cells. No single causative factor has been identified, although viral and bacterial infections have been linked to NHL, and genetic and immunological factors may be implicated. The incidence is higher than that of Hodgkin’s disease, at 12 new cases per 100,000 population a year, and the median age of diagnosis
is 65–70 years. Suppression of the immune system that occurs in people with HIV infection has been linked with a marked rise in the incidence of non-Hodgkin’s lymphoma and Hodgkin’s disease. Most patients have painless swelling of one
or more groups of lymph nodes in the neck or groin, and the liver and spleen may enlarge. As other organs can also be affected, patients may present with a wide range of symptoms, including fever, itching and weight loss. If NHL occurs in a single group of lymph nodes, radiotherapy is the treatment of choice; more extensive infiltration of glands will require
chemotherapy – and sometimes both types of treatment will be necessary. If these treatments fail, BONE MARROW TRANSPLANT may be carried out. Prognosis is good for low-grade NHL (75 per cent of patients survive five years or
more); in more severe types the survival rate is 40–50 per cent for two years. Another variety of lymphoma is found in
children in Africa, sometimes called after Burkitt, the Irish surgeon who first identified it. Burkitt’s lymphoma is a rapidly growing malignant tumour occurring in varying sites, and the Epstein Barr virus has a role in its origin and growth. A non-African variety of Burkitt’s lymphoma is now also recognised. CYTOTOXIC drug therapy is effective.
