Early birth control lowers risk of ovarian, uterine cancers later

Washington: Researchers have edged a step closer to understanding why past oral contraceptive use dramatically lowers the risk of ovarian and uterine cancers later in life.
Latanya M. Scott of Wake Forest University School of Medicine discovered that monkeys who had been given birth control earlier in life had a reduced amount of oestrogen excreted in their urine.

The research was done in collaboration with Xia Xu and Timothy Veenstra, at Science Applications International Corporation-Frederick, who have developed novel methods for analysis of urinary oestrogens.

The discovery was particularly noteworthy because it was found three years after oral contraceptive treatment was stopped, roughly the equivalent of a decade of life in a human, said a Wake Forest University press release.

The study appeared in this month's issue of Cancer Epidemiology, Biomarkers and Prevention.While researchers have known for many years that past oral contraceptive use significantly lowers the risk of ovarian and uterine cancers later in life, this new observation in monkeys may shed light on the mechanism behind the cancer-protective effect of the treatment.

While researchers don't yet understand the precise mechanism by which hormone levels are being affected, they do know that both the level of oestrogen in the blood and the amount of oestrogen being excreted in urine are lowered with past oral contraceptive use, which may mean that the oral contraceptive use is somehow leading to a diminished synthesis of oestrogen.

"Hormone exposure has long been known to be important in cancer risk," said J. Mark Cline, and senior project researcher. "These effects are robust, and we believe this discovery could be translated fairly quickly into a study in women.

""If our results are confirmed to also occur in women, they could change the way we look at oral contraceptives and cancer risk," added Cline, a professor of pathology and comparative medicine at Wakefield.Funded by the National Institutes of Health, researchers based their findings on a study of 181 premenopausal cynomolgus monkeys and followed them for seven years to look at hormone effects on many aspects of female health