Incidence of central nervous system tumours with the use of hormone replacement therapy
Background
Approximately 4300 people are diagnosed with a brain or other central nervous system (CNS) tumour annually in the UK. They have poor prognosis, yet little is known about risk factors of the tumours.
Objectives
To investigate the role of hormone replacement therapy (HRT) and the risk of brain and CNS tumours, specifically gliomas, meningiomas, and acoustic neuromas in post-menopausal women.
Participants and Setting
1.1 million post-menopausal women were recruited from breast screening clinics from 1996–2001 in England and Scotland and followed for incident tumours through NHS cancer registration. All CNS tumours and each of the tumour types (glioma, meningioma, and acoustic neuroma) were separate end points in a Cox proportional hazards model for investigation of various measures of HRT use.
Main Outcome Measure
Relative risk (RR) of incident CNS tumours (classified as malignant or benign) relating to the use of HRT, adjusting for age, socioeconomic status, region of residence, height, and body mass index.
Preliminary Results
A total of 1163 post-menopausal women with HRT information were diagnosed with a tumour of the brain or CNS; 517 tumours were classified as glioma, 280 as meningioma, and 113 as acoustic neuroma. Preliminary findings show that current users of HRT were more likely to develop a CNS tumour when compared to never users (RR 1.18, 95% CI 1.03 to 1.35). Findings by type of HRT use and by the histological subtype of the tumours will be presented.
Conclusion
Current users of HRT are at a slightly increased risk of developing CNS tumours.
