Although the origins of ovarian cancer are murky at best, Danish researchers may have uncovered a link between this deadly form of cancer and hormone therapy. Regardless of when or for how long women were treated, the estrogen dosage or the specific treatment regimen, women who have taken hormone therapy at some point in their lives may have an elevated risk of ovarian cancer.

While reviewing the health records of some 900,000 Danish women between ages 50-79 from 1995-2005, researchers found 31 percent of the patients had used or were using hormonal therapies. And, nearly half of the women currently using hormone therapy (46 percent) had been following their treatment regimen for more than seven years.

The number of ovarian cancers identified during an eight-year follow-up period amounted to 3,068 cases, with the majority linked to epithelial tumors (2,681). Women who actively took hormone therapies elevated their risk of ovarian cancer by 38 percent, compared to those who never used it.

Unfortunately, when scientists narrowed their focus to epithelial tumors, the numbers worsened: Ovarian cancer risks rose significantly among women who were currently using hormone therapy (44 percent) and those who had stopped using it (15 percent), compared to those who avoided such therapies.

Although current or previous use of hormone therapies resulted in a 5 percent increase overall -- not a huge number -- women should take into account the high fatality rate among ovarian cancer patients when considering hormone therapy, researchers said.

Journal of the American Medical Association, Vol. 302, No. 3, p. 298-305, July 15, 2009

ScienceDaily July 15, 2009

WebMD July 14, 2009