Progestin is the ingredient in oral contraceptive
pills that provides the highest level of protection against
ovarian cancer, researchers have found.
Analysis by the Duke Comprehensive Cancer Center
of a 20-year-old study that showed the pill can help prevent
ovarian cancer found that the cancer risk was cut by about
50 percent in all women taking pills containing the hormones
estrogen and progestin.
However, women who took pills containing high
levels of progestin reduced their risk of ovarian cancer by
an additional 50 percent, said Patricia G. Moorman, a Duke
University Medical Center researcher and the co-author of
a study in the Journal of the National Cancer Institute.
"The take-home message from this study
is that oral contraceptives are protective against ovarian
cancer and our finding that the high progestin potency effect
is a scientific (result) that might lead to new protective"
drugs against ovarian cancer, Moorman said.
The study is based on a re-examination of the
medical and oral contraceptive histories of more than 3,200
women who took part in a study project conducted from 1980
to 1982. The group included 390 women who developed ovarian
cancer and 2,865 who did not. It compared the ovarian cancer
outcome among women who did not take the pill and with women
who took different formulations of the pill.
The groups included women who took no pills;
those who took pills high in both estrogen and progestin;
women who took pills high in one or the other of the hormones,
and women who took pills with low levels of both hormones.
Moorman said earlier results had proven that
the pill protects against ovarian cancer, while the new study
shows which of two hormones in the pill, estrogen and progestin,
are most protective.
She said the study "should lead to the
investigation of progestin as a chemopreventative agent for
ovarian cancer."
Moorman said the pills used by the women in
the study 20 years ago are not now commonly available. She
said birth control pill formulations have changed over the
years as research showed that pills with lower hormone levels
were effective contraceptives. Pills with lower levels of
hormone generally have fewer side effects.
Ovarian cancer is the sixth most common cancer
among women, excluding the skin cancers. It accounts for about
4 percent of all cancers in women, with more than 23,000 new
cases diagnosed in 2001, according to the American Cancer
Society. 1/4
Nearly 14,000 American women died of ovarian
cancer in 2001.