Low T Levels Linked to Lower Prostate Cancer Risk?

Low testosterone levels have been shown to be linked to a lower risk of prostate cancer (PC). A new study conducted by researchers at the University of Oxford analyzed blood samples from 19,000 men ages 34-76 collected between 1959 and 2004. The findings from this research were recently presented at the National Cancer Research Institute (NCRI) in Liverpool. In this analysis, which is the largest of its kind conducted to date, researchers found that men with “unusually low” amounts of testosterone in their blood were 20% less likely to develop prostate cancer.

The prostate / testosterone connection

Prostate cancer is the second most frequently diagnosed cancer and the sixth leading cause of cancer death in men worldwide. It generally affects older men, grows slowly and is most often treatable. Prostate cancer can often be “cured” with surgery or radiation if it is treated when localized or at lower stages, however, for many men, there is still a risk of cancer recurrence. The prostate, a gland that is part of the male reproductive system, has testosterone receptors, and thus the growth of cancerous cells in the prostate and beyond is affected by testosterone levels.

Prostate cancer, like breast cancer, is a condition influenced by hormones. It needs testosterone to multiply and spread. Most prostate cancer tumors that spread have overactive testosterone receptors. Hormone therapy, also called androgen deprivation therapy (ADT) or androgen suppression therapy, is used to block or lower the levels of testosterone in the body.1 Decreasing the androgen levels or preventing them from invading prostate cancer cells can cause prostate cancer tumors to shrink or grow less quickly. Hormone therapy alone does not cure prostate cancer.

The UK study

Scientists continue to explore the causes of prostate cancer development, as well as prevention, detection, and treatment of, prostate cancer. The UK study analyzed data from 19,000 men and divided them into ten groupings or cohorts based on the free circulating testosterone levels in their blood and compared their prostate cancer risk. The findings indicated that those with lowest testosterone levels, in the bottom tenth, were less likely to develop the disease. However, those findings do not mean that they would not get prostate cancer. Additional findings suggest that men that did develop prostate cancer were 65% more likely to develop a more aggressive form of the disease. There was no direct correlation with the development of the disease and level of testosterone for the other nine study cohorts.

The study authors suggest that their findings support “the hypothesis that testosterone receptors on prostate cells quickly become saturated. It appears that once that level has been reached, further increases in testosterone do not increase cancer growth.”1 This theory has not been supported through years of prior studies, so this is an important finding to come forward. The saturation model suggests that the stimulating effects of hormones increase up until the point of receptor saturation, but any further increase above that will not cause additional growth in prostate tissue.5

Future research

According to Professor Malcolm Mason, a prostate cancer expert for Cancer Research UK, “These results could be important in helping to devise an approach to reducing men’s risk of developing the disease.” While this research does not offer any definite conclusions about how treatment options might be adapted to incorporate findings of “unusually low” testosterone levels, it does point the way for further studies. Further exploration of the biology of the disease might lead to techniques for earlier identification of risk factors for the diagnosis and treatment of prostate cancer.1

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