Drop in Testosterone Linked To Prostrate Cancer Recurrence

One of common cause of death from cancer in men over age 75 is prostate cancer. Rarely found in men younger than 40, this prostate cancer is less common in people who do not eat meat.

A latest finding on this disease is that men whose testosterone levels fell following different forms of radiation therapy were more likely to experience an increase in prostate specific antigen (PSA). This is the early indication that the cancer has recurred.

This has been stated in a study conducted by the researchers from Fox Chase Cancer Center.

"The men who had a decrease in testosterone also appear to be the men more likely to see an increase in PSA after treatment," says study author Jeffrey Martin, MD, resident physician in the Department of Radiation Oncology at Fox Chase.

In this theory, the doctors may one day be able to use testosterone levels to guide treatment decisions.

According to Martin "for men with a decrease in testosterone, doctors might intervene earlier with other medications, or follow their PSA more closely than they would otherwise, to spot recurrences at an earlier time."

In order to prove their hypothesis, Martin and his colleagues decided to conduct a study as they had limited information regarding testosterone levels after radiation treatment and what it meant for prognosis.

For this the researcher's analyzed medical records from nearly 260 men who received radiation therapy for prostate cancer between 2002 and 2008. The men were treated with either brachytherapy or intensity modulated radiation therapy (IMRT). In brachytherapy the doctors inserted radioactive seeds in the prostate whereas in IMRT an external beam of radiation is directed at the prostate.

On doing so the researches noticed that testosterone levels tended to decrease following both forms of radiation therapy. Men who experienced a post-radiation drop in testosterone were more likely to see their PSA levels rise during the follow-up period. The authors noticed that an increase in PSA was relatively rare.

"Only 4 percent of patients with low-risk prostate cancer had biochemical failure at five years," says Martin.

"Even though researchers have seen testosterone decrease following another form of radiation, these latest findings are still somewhat surprising," says Martin. "Because testosterone is believed to drive prostate cancer. In fact, some patients with advanced forms are prescribed hormone therapy that attempts to knock down testosterone."

 "Seeing that a drop in testosterone is tied to recurrence is kind of a surprising result," says Martin. "We don't necessarily know what this means yet. I think the relationship between testosterone levels following radiation therapy and prognosis needs more study, and until then it's premature to say this is something patients should ask their doctors about."

 According to the study, a further analysis is required in a larger group of men before doctors begin basing their prediction

 "I think the link between testosterone and PSA needs more study, in a larger set of patients."

 The findings will be presented on October 29 at the American Society for Radiation Oncology's 54th Annual Meeting.