Lymphoma comprises a collection of cancers that develop in the lymphatic system and affects the lymphocytes. Broadly, lymphoma is split into two categories: Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). In lymphoma, all parts of the lymphatic system can be affected and the disease can be extranodal. NHL includes all subtypes of lymphoma except for HL and there are more than 60 types – making it the most common type of hematological malignancy. NHL is classified into B-cell and T-cell NHL, depending upon which types of lymphocyte are affected.

HL is a rare cancer, accounting for around 0.5-1% of all new cancer cases in the UK and US. Conversely, NHL is the 7th most common cancer in the UK and US. The NIH reports that 86.4% of people diagnosed with HL and 71% of those with NHL survive for 5 years or more (based on data from SEER 18 2007-2013).

The risk factors for lymphoma are varied and not fully characterized, including EBV infection (responsible for around half of HL cases), a weakened immune system, previous cancer, age and gender, and genetic and lifestyle factors.

Treatment depends on the type of lymphoma, as well as its location and stage. The main treatments for HL are chemotherapy and radiotherapy, whereas the treatment for NHL can be more varied, including stem cell transplants. Low-grade lymphomas may remain indolent for year, whereas high-grade lymphomas are more aggressive. However, paradoxically, high-grade lymphomas often have better prognoses and are easier to treat. Recent treatment developments for lymphoma include novel chemotherapy regimens, CAR T-cells, antibody-drug conjugates, checkpoint inhibitors, targeted therapies and proton beam therapy.