"Free testosterone comprises one to two percent of total testosterone and is considered a useful surrogate for the biologically active portion of circulating testosterone."
New York, May 5 - Low levels of testosterone can be associated with aggressive prostate cancer and indicate worsening of the disease in men who are afflicted by it, a significant study has said.
These results suggest low levels of testosterone are associated with more aggressive prostate cancer, said Ignacio San Francisco from Pontifical Catholic University of Chile.
This contradicts long-held beliefs that high testosterone is risky for prostate cancer, and low testosterone is protective, San Francisco added.
The findings could help physicians identify patients with low-risk prostate cancer who should receive aggressive anticancer treatment.
For the study, the researchers monitored 154 men with low-risk prostate cancer for 38 months.
Low levels of free testosterone were significantly linked with an increased risk of developing more aggressive disease, the findings of the research showed.
They found no significant association with total testosterone concentrations, although there was a general trend towards increased risk with lower levels.
Free testosterone comprises one to two percent of total testosterone and is considered a useful surrogate for the biologically active portion of circulating testosterone.
The study appeared in the journal BJU International.