1 in 36 UK males and 1 in 47 UK females will be diagnosed with melanoma skin cancer in their lifetime. However, 86% of melanoma cases are preventable, as many cases are caused by UV ray exposure, but other factors can also play a role in who is most at risk, such as age and genetics.
A recent study lead by Dr Eleanor Watts at the Nuffield Department of Population Health has now found that testosterone is one of these risk factors. Published in the International Journal of Cancer, the team found that men with high levels of testosterone have an increased risk of developing a potentially deadly type of skin cancer. This was a result of studying blood samples hormone data. collected by the UK Biobank from 182,600 men and 122,100 postmenopausal women aged 40 to 69.
The researchers looked both the total level of testosterone in the blood samples, as well as levels that were freely circulating – in other words testosterone that was not bound to proteins. They then used national registries and NHS records to explore whether participants went on to develop or die from cancer.
The results show that by 2015-16, after being followed for an average of seven years, 9,519 men and 5,632 postmenopausal women – 5.2% and 4.6% of participants respectively – had been diagnosed with a malignant cancer. By excluding other, non-melanoma diagnoses and accounting for other factors they found that for men, higher levels of testosterone, whether freely or in total, were associated with a greater risk of developing malignant melanoma.
Specifically, each 50 pmol/L increase in free testosterone was found to raise the chance of developing this cancer by 35%. According to Eleanor, 90% of men included in the study had free testosterone concentrations of between 130 pmol/L and 310 pmol/L.
Among other findings, higher levels of freely circulating testosterone were associated with a greater risk of prostate cancer in men, while in post-menopausal women, higher levels of testosterone, whether freely circulating or in total, were associated with a greater chance of endometrial and breast cancer.
Dr Eleanor Watts, the first author of the research from the University of Oxford, says:
“There has been indirect evidence for testosterone and melanoma before, but this is the first time we have been able to look directly at the hormones in the blood
“Although we have seen associations of prostate, breast and endometrial cancer with testosterone before, this is the first time we have seen an association with risk of melanoma in men.”
Eleanor is an Early Career Research Fellow in the Cancer Epidemiology Unit (CEU), part of the Nuffield Department of Population Health. Her research examines the role of endogenous hormones on prostate cancer risk using UK Biobank.