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Why some men have an increased risk of prostate cancer
Men with a higher level of free testosterone and a growth hormone in the blood are much more likely to develop prostate cancer.
A study by the University of Oxford's Nuffield Department of Population Health found that free testosterone and a growth hormone in the blood contributed to an increased risk of prostate cancer in men. The results of the study were presented at the 2019 NCRI Cancer Conference.
How is the risk of prostate cancer increased?
Factors such as age, ethnicity, and a family history of the disease are known to increase a man's risk of developing prostate cancer. The current study of more than 200,000 men found evidence of two factors that could potentially be modified to reduce the risk of prostate cancer.
Results could reduce risk of prostate cancer
"Prostate cancer is the second most diagnosed cancer in men worldwide after lung cancer and one of the most common causes of cancer death, but there is no evidence-based advice we can give men to reduce their risk," said study author Ruth Travis.
"We were interested in examining the levels of two hormones that circulate in the blood because previous research indicated that they could be associated with prostate cancer and because these are factors that could potentially be changed to reduce the risk prostate cancer, ”the expert added in a press release.
What is Free Testosterone?
The 200,452 men examined were all cancer free when they joined the study, and none of the participants received hormone therapy. The men gave blood samples that were tested for their testosterone levels and the growth hormone insulin-like growth factor-I (IGF-I). The researchers then calculated the free testosterone content. This testosterone circulates in the blood and is not bound to any other molecule.
A subset of 9,000 men later gave a second blood sample to help researchers explain natural fluctuations in hormone levels. The men were medically monitored for an average of six to seven years to see if they continued to develop prostate cancer. There were 5,412 cases and 296 deaths from the disease within the group.
How much was the risk increased?
Men with higher concentrations of the two hormones in the blood were more likely to be diagnosed with prostate cancer. For every five nanomoles increase in IGF-I concentration per liter blood (5 nmol / L), men developed prostate cancer nine percent more likely. For every increase of 50 picomoles of free testosterone per liter of blood (50 pmol / L) there was a ten percent increase in prostate cancer risk.
Based on the total sample, the results correspond to a 25 percent higher risk for men with the highest IGF-I values than for men with the lowest values. Men with the highest free testosterone levels face an 18 percent higher risk of prostate cancer compared to men with the lowest levels.
Strategies for prostate cancer prevention in prospect?
Because blood tests were done a few years before prostate cancer developed, hormone levels are more likely to lead to an increased risk of prostate cancer. This is in contrast to the types of cancer that lead to higher hormone levels.
The results show that the two hormones examined could be a mechanism that links things like diet, lifestyle, and height to the risk of prostate cancer. As a result, the researchers believe that they have come one step closer to effective strategies to prevent prostate cancer. (as)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.