The pill still fights cancer years later, research says
Cancer study lauds birth control pills
Pre-menopausal and menopausal women could reduce their risk of ovarian cancer with birth control pills, a new Hawaii study suggests.
Cancer Research Center of Hawaii investigators compared similar populations of women with, and without, ovarian cancer in a study in Hawaii and Los Angeles.
Previous studies showed birth control pills guard against ovarian cancer, but hormones in oral contraceptives have been reduced in recent years and researchers did not know whether they were still beneficial.
AT A GLANCE
» Cancer of the ovary is the fifth most common cause of cancer deaths in women.
» The American Cancer Society estimates about 22,430 cases of ovarian cancer will occur this year in the United States, and 15,280 women will die.
» Hawaii can expect about 50 new cases and 35 deaths, if national rates are applied.
Source: Cancer Research Center of Hawaii
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The new study found pills with lower doses of estrogen and progestin provide similar protection against ovarian cancer and that the longer women use them, the more protection they get.
Also, the researchers said, protection lasts up to 30 years after a women stops taking them.
Lower doses of hormones in oral contraceptives provide the same protection against ovarian cancer as higher doses, University of Hawaii researchers have found.
Moreover, protective effects last 15 to 30 years after women stop taking the pills, they report.
If pre-menopausal women took oral contraceptives, "it could have a phenomenal impact on the toll this terrible disease takes in this country," said gynecologist-oncologist Michael Carney. "Nobody takes a birth control pill after menopause, but maybe they should."
Carney worked on the study with Drs. Marc Goodman and Galina Lurie at the Cancer Research Center of Hawaii. The new findings are part of a broad ovarian cancer study conducted by Goodman and his colleagues since 1995. They previously reported that women who use oral contraceptives reduce their risk of ovarian cancer by 40 percent or more.
But estrogen and progestin doses have been reduced in birth control pills in recent years, and the effects were not known, said Lurie, an epidemiologist and biostatistician.
Goodman's study presented a chance to compare 745 women diagnosed with ovarian cancer with 945 cancer-free women of similar age and ethnicity in Hawaii and Los Angeles, she said.
Lower-dose pills had the same positive results as higher doses, and "doses are going even lower," she said. Some women are taking progestin-only pills, she said. "Future studies will be needed to compare those."
Carney cited many reasons to take oral contraceptives besides preventing pregnancy. Menstrual periods are lighter, more predictable and not as painful, he said. And with some new formulations, a woman has a period only three or four times a year instead of monthly, he said.
Goodman said there is little difference in the pregnancy risk from reduced estrogen/progestin in oral contraceptives and that lower levels reduce side effects.
The question was whether the lower doses reduced the risk of ovarian cancer, and they do, Goodman said. "More importantly, even short duration of use has a significant effect on risk.
"So even women who used oral contraceptives less than five years, or even a few years, still derive benefit from it." The longer women use it, the more protection they have, he said.
Women who took only progestin also were protected from ovarian cancer, Goodman said, adding, "That was interesting because a lot of people think it's the progestin component alone that's important."
Carney, medical director of the Women's Cancer Center at Kapiolani Medical Center for Women & Children, said, "Another blockbuster finding is that patients get up to a 40 percent reduction in risk of ovarian cancer up to 30 years after stopping taking the contraceptive pill.
"Too bad it isn't 100 percent, though. Unfortunately, I see patients every month that have taken the contraception pill religiously and developed ovarian cancer."
Goodman said a tissue repository was set up with Carney for the study and future research on molecular markers for cancer.
Epidemiological and other studies suggest progesterone might be "kicking ovarian cells into death" so they cannot progress to cancer, Carney said. But there is not enough data to say the progestin pill alone is enough to provide long-term protection, he said.
The researchers reported their findings in the medical journal Obstetrics & Gynecology, and Carney recently presented them at a national meeting of the Society of Gynecologic Oncologists.
