A Prospective Cohort Study Of Risk Factors For Prostate Cancer In 230,000 Men From UK Biobank

Ruth TRAVIS, University of Oxford, United Kingdom
FENSOM G. 1 , KEY T. 1 , ADAMSKA L. 2 , HAMDY F. 3 , LILJA H. 3,4 , LITTLEJOHNS T. 2 , MARTIN R. 5 , ALLEN, ON BEHALF OF THE UK BIOBANK PROSTATE CANCER N. 2

1 Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
2 Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, UK
3 Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
4 Departments of Laboratory Medicine (Clinical Chemistry Service), Surgery (Urology Service), and Medicine (Genitourinary Oncology Service), Memorial Sloan Kettering Cancer Center, New York, USA; Department of Translational Medicine, Lund University, Malmo, Sweden.
5 School of Social and Community Medicine and MRC Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom

Purpose
Prostate cancer is the commonest cancer among men in the UK, yet there are no known modifiable risk factors to inform prevention. With the aim of advancing the understanding of the aetiology of prostate cancer, in 2013 we initiated the UK Biobank Prostate Cancer Epidemiology Consortium to exploit the maturing UK Biobank resource with its uniquely detailed exposure phenotyping.

Methods
Between 2006-2010 the UK Biobank study recruited 500 000 participants aged 40-69 from across Britain. We examined the baseline characteristics of the 230,000 men in UK Biobank in relation to risk of prostate cancer using Cox regression, stratified by age at entry and region, with adjustment for potential confounders, and using attained age as the underlying time variable.

Results
After an average of 2.9 years of follow-up, by 31st December 2011 there were 1888 incident cases of prostate cancer. Preliminary analyses show that risk of being diagnosed with prostate cancer was elevated for men with known risk factors including family history of prostate cancer (HR 1.99, 95% CI 1.73 to 2.29 for men with any versus no first degree family history) and black ethnicity (HR 3.45, 95% CI 2.47 to 4.82 for black versus white ethnicity). Further endpoint data will be available in January 2016 and results from the extended analyses for a wide range of putative risk factors will be presented.

Conclusions
By 2017 there will be 5000 incident cases of prostate cancer in UK Biobank. Future analyses will examine risk factors for distinct prostate tumour subtypes, with a particular focus on high risk disease (including advanced stage and high grade tumours) and on the exposures infrequently characterised in large prospective cohort studies, including medical history, early development, sexual history, sophisticated measures of body composition, metabolic profile and biomarkers of infection.

Funding
Cancer Research UK