Treatment for prostate cancer can be self-defeating

August 22nd, 2008 - 11:46 am ICT by IANS  

Washington, Aug 22 (IANS) Some of the drugs administered for treatment of prostate cancer can be self-defeating; they actually spur cancerous cells to grow, according to new research.The findings could help explain why such failures have bedevilled patients for decades. Hormone therapy, a common treatment for advanced prostate cancer, fights the condition for a year or two.

But for reasons never fathomed by scientists, the treatment fails in patients with a worsening condition. The cancer begins to grow again, at a time when they have fewer treatment options.

These findings by Chawnshang Chang and his team at the University of Rochester Medical Center offers the explanation that the androgen receptor, through which male hormones like testosterone work, is much more versatile than previously thought.

Under certain conditions the molecule spurs growth, and at other times the molecule squelches growth - just like the same molecule does to hair in different locations on a man’s head.

Chang said the molecule’s versatility in the prostate should not come as a surprise, since the molecule’s function elsewhere depends on its location.

For example, “when the receptor is very active in the moustache area, more hair grows. When it’s very active on the top of the skull, toward the front, hair falls out and men become bald. And the hair on the back of the head is insensitive to the receptor. The effects of hormones depend on the location”.

The new findings suggest the possibility that under some conditions, some treatments designed to treat prostate cancer could instead remove one of the body’s natural brakes on the spread of the disease in the body.

The researchers stress that the results are based on lab studies and on findings in mice, and it’s too soon to know yet whether the findings apply directly to prostate cancer in men.

Understanding the effects of the androgen receptor gives physicians a toehold in efforts to develop more effective treatment in prostate cancer. That would be welcome news for the one of every six men who will develop the disease during his lifetime.

More than 28,000 men die from the disease in the US every year, according to the American Cancer Society. Men’s risk from prostate cancer is about the same as women’s risk from breast cancer.

Every year both the genders face the risk of dying equally from their respective conditions, according to ACS.

Chang’s findings are most relevant for patients with advanced prostate cancer, who typically receive hormone therapy after other treatments such as surgery or radiation.

With hormone therapy, physicians blunt the effects of male hormones like testosterone to bring the disease in the prostate to a halt. One form of hormone therapy works by blocking the androgen receptor.

The findings appeared online this week in the Proceedings of the National Academy of Sciences.

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