Published online by Cambridge University Press: 05 November 2015
The incidence of lymphoma is rising, and current attention is focused not just on improving cure rates, but also on minimising late effects of treatment. Patients should be managed by multidisciplinary teams that bring together the appropriate expertise of haematologists, oncologists, radiologists, pathologists and specialist nurses. Management guidelines are produced by the British Committee for Standards in Haematology (BCSH) and are a useful resource.
The World Health Organisation (WHO) classification of neoplasms of the hematopoietic and lymphoid tissues was first published in 2001 and updated in 2008 (Table 34.1: Swerdlow et al., 2008). This distinguishes more than 60 specific entities on the basis of morphologic, immunophenotypic, genetic, molecular and clinical features, stratified according to cell lineage and derivation from precursor or mature lymphoid cells.
Non-Hodgkin lymphoma (NHL) is the sixth most common cancer in the UK, with over 12,000 patients diagnosed each year, accounting for 4% of all new cases of cancer. The incidence is related to age, with the majority of cases diagnosed over the age of 65 years. Nearly half of all cases diagnosed in the UK are diffuse large B cell lymphoma (DLBCL, 48%). Marginal zone lymphomas (MZL) and follicular lymphoma (FL) account for 20% and 19%, respectively, with T cell lymphomas (6%), mantle cell lymphoma (MCL, 5%) and Burkitt lymphoma (2%) making up the remainder. Crude incidence rates in the UK range from 0.2 to 9 cases per 100,000.
Hodgkin lymphoma (HL) accounts for 0.6% of all cancer cases, with a relatively stable incidence of around 1700 cases per year. In children under 14 years of age, lymphoma is the third most common cancer after leukaemia and brain tumours. Lymphomas are the most common cancer in teenagers and young adults, accounting for 21% of cancers in this age group, with two-thirds of these being HL.
The aetiology of lymphoma is not clearly understood and appears to be multifactorial. The most significant risk factor is immune dysfunction which may be secondary to viral infection (e.g. HIV, HBV, HCV, EBV, HTLV-1), autoimmune disease or iatrogenic immunosuppression (Roman and Smith, 2011). Mucosa-associated lymphoid tissue (MALT) lymphomas are associated with antigenic stimulation by infectious agents including Helicobacter pylori, Chlamydia psittaci and Borrelia burgdorferi.