Why did we do this research?
Although the causes of most haematological malignancies are largely unknown, proposed links have been suggested between lymphoid disease and autoimmune conditions (where an individual’s immune system acts against their own body), as well as joint replacements, potentially due to the materials used in these procedures. Current evidence on these associations is conflicting, however, and information on specific subtypes is lacking, so we wanted to explore these issues further within HMRN. We investigated associations between rheumatological conditions, and joint replacements, with the development of lymphoid malignancies.
What did we do?
We routinely collect information about patients with haematological malignancies diagnosed in the 14 hospitals within our area, and NHS Digital supply us with information about their hospital attendances, cancer diagnoses and deaths. To investigate potential causes of haematological malignancies, NHS Digital matched each member of our patient cohort to ten people, born in the same year, who do not have a haematological malignancy, therefore generating a general population comparison cohort, referred to as ‘controls’. We have the same NHS Digital information for these ‘controls’ as has been provided for our patients.
What did we find?
We found that people with rheumatological conditions were more likely to develop certain haematological malignancies (such as diffuse large B-cell lymphoma and marginal zone lymphoma), but not other lymphoid cancers (including chronic lymphocytic leukaemia, follicular lymphoma and myeloma). These results support the role of immune dysregulation in the development of some mature B-cell malignancies. We also found that a similar percentage of haematological malignancy patients and ‘controls’ had a joint replacement. Importantly, however, having a previous joint replacement was associated with an increased risk of myeloma, monoclonal gammopathy of undetermined significance (MGUS: a precursor condition that sometimes develops into myeloma) diffuse large B-cell lymphoma and classical Hodgkin lymphoma. It is important to note that very few haematological malignancies were diagnosed after the joint replacements, that the absolute risk of disease is low, and that the associations we identified do not necessarily mean joint replacements will cause the malignancies to develop.
Other work into haematological malignancy precursor conditions and the long-term effects of cancer treatment, as part of this project, is ongoing.
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