(WOMENSENEWS)--Women who take oral contraceptives for at least five years reduce their chances of getting ovarian cancer for as long as 20 years after they swallow their last pill, according to a November report in the International Journal of Cancer. The long-term benefit is especially helpful because ovarian cancer is more common in mid-life, 10 times more frequent at age 60 than at age 30.
Ovarian cancer is especially deadly because its early symptoms of bloating, pain andabdominal discomfort are easily confused with other ailments and there is still no easy, reliable screening method for the disease, according to the Ovarian Cancer National Alliance. Consequently, about 80 percent of ovarian cancer patients are diagnosed at an advanced, deadlier stage of the disease. Caught early, the disease is treatable.
Many questions about this type of cancer, however, and prescribed hormones remain unanswered. For example, still unclear is whether prolonged use of the pill followed by years of hormone replacement therapy at menopause increases the risk of cancer or cardiovascular disease. As the first generation of women to take the pill enter menopause, the Women's Health Initiative is examining data on more than 16,000 women to provide some answers. Results are due this year.
Researchers think the pill protects by reducing or stopping ovulation, explains Dr. Roberta Ness, a professor of epidemiology, medicine, obstetrics and gynecology at the University of Pittsburgh.
"We know that oral contraceptives reduce the number of ovulations--that's their very purpose. So it's not surprising that oral contraceptives would reduce the risk and reduce it for a very long time thereafter," Ness says.
Ovulation also stops temporarily during pregnancy and breast-feeding, two known risk reducers for ovarian cancer. Others are tubal ligation and hysterectomy.
Questions about the Difference between the Pill and Hormone Replacement
Both oral contraceptives and hormone replacements are chemical variations on the hormones estrogen and progesterone. In December, the U.S. government's National Toxicology Program added the estrogen compounds used in these drugs to its list of carcinogens because they seem to increase the risk of endometrial and breast cancer.
This, in addition to a 2002 Women's Health Initiative study reporting heightened risks of breast cancer, heart attack and stroke from taking Prempro, the most widely used hormone replacement drug, has raised the safety concerns about birth control pills.
"For oral contraceptives taken during a woman's normal reproductive period, that is, in her 20s and 30s," Ness says, "there's not the evidence for increased risk of cancer. But there is some concern that as women get into their 40s and are still taking oral contraceptives, there may be some increased concern.
"Oral contraceptives and Hormone Replacement Therapy are totally 100 percent different situations," she adds. "Oral contraceptives are taken during the time when a woman already has high and low estrogen levels cyclically and HRT is taken when a woman has very low endogenous, or her own, hormone levels."
Until fairly recently, Ness says, some women under age 35 avoided taking oral contraceptives before their first pregnancy because of research showing that it increased their risk of breast cancer. But the latest research, she says, counters this finding, showing no increased risk from the pill.
For women under age 35, Ness says, the pill is an excellent contraceptive choice, even considering the standard cautions concerning blood clots and hypertension. For women over age 35 who don't smoke, she adds, the pill is still recommended, having a "very small" risk of thrombosis for that group.
However, women with certain types of gene mutations, known as BRCA1 and BRCA2, are at greater risk for both ovarian and breast cancer. Research announced in December in the Journal of the National Cancer Institute found that women with the BRCA1 gene mutation who took the pill before age 30, for more than five years, or before 1975 (when its estrogen levels were much higher) had an increased risk of breast cancer. More research is needed on BRCA2 carriers.
The researchers advise women with the BRCA1 and BRCA2 mutations to wait until age 30 to begin taking the pill, theorizing that the delayed start will protect the women from ovarian cancer while minimizing their breast cancer risk.
"It's my strong recommendation that women who have a family history of ovarian cancer and no other contraindications use oral contraceptives," says Dr. Daniel Cramer, professor of obstetrics and gynecology at Boston's Brigham and Women's Hospital and a physician with the Dana-Farber Cancer Institute. This advice may not apply to women who smoke or have a history of blood clots or high blood pressure.
Cramer welcomes the latest findings on the pill's long-term benefits, but says he's not surprised.
"I think to some extent taking the birth control pills does keep the ovaries healthier," Cramer says, adding that the pill also reduces the risk of ovarian cysts.
"Women at risk for ovarian cancer certainly should consider using the birth control pill and women not [at risk] should put this in the balance of risks and factors they consider in deciding what contraceptive method to use."
Suzanne Batchelor has written for the national science series "Earth and Sky" and on health and medicine for Medscape Health, Web MD and the Texas Medical Association's "Healthline Texas."
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For more information:
International Journal of Cancer:
"Long-term effects of oral contraceptives on ovarian cancer risk":
Ovarian Cancer National Alliance:
National Ovarian Cancer Coalition:
http://www.ovarian.org and 1-888-OVARIAN