Androgen-independent prostate Ca more likely to metastasize

Prostate cancers that are resistant to androgen deprivation therapy are more invasive and are more likely to spread to other organs than are androgen-dependent prostate cancers, according to UCLA researchers. The findings could change the way some prostate cancers are treated, spurring earlier use of hormone therapy to prevent the cancer’s spread, said senior author Robert Reiter, MD.

Published in Cancer Research (2008; 68:1128-35), the study connects androgen receptors with the spread of prostate cancer and the progression to androgen independence. Previous studies have shown that the androgen receptor is responsible for the growth of hormone-refractory prostate cancer; however, none associated the spread of prostate cancer with the androgen receptor.

“We started noticing that the castration-resistant prostate cancer models in the lab seemed to express genes that are typically associated with the spread of cancer,” Dr. Reiter said. “We looked at the androgen receptor and were surprised to find that it was not only overexpressed in castration-resistant cancers, but also in invasive cancers that still relied on androgen to grow.”

The study found that overexpression of the androgen receptor was critical to the cancer becoming more invasive. If a therapy could be found that blocked overexpression of the receptor, it might prevent the spread of certain prostate cancers.

“Early hormone treatment in this group of men might allow them to live longer. High levels of androgen receptor in the primary tumor might also predict which cancers are more likely to spread, despite initial surgery or radiation.” Dr. Reiter explained.