Oral contraceptives or birth control pills are statistically linked to significant and permanent reductions in the risk of ovarian and endometrial cancer, researchers at Uppsala University in Sweden reported last month.
Research confirms previous findings linking oral contraceptives to an increased risk of breast cancer, the second most common cancer diagnosed in women. However, the new study, published in Cancer Research, provides evidence that the benefits of birth control pills for cancer may outweigh the risks for a large segment of the female population.
Investigators analyzed medical data on 256,661 women born in the United Kingdom between 1939 and 1970. Those who were currently taking or had previously taken birth control pills were classified as “Ever Users” (82%), while those who had never taken them were classified as “Never Users” (18%). Over the decades, 17,739 breast cancer have been diagnosed, 1,966 ovarian cancer and 2,462 endometrial cancer.
Using several statistical analysis techniques, the researchers found that while users had a slightly increased risk of breast cancer (10%), they had a significantly reduced risk of ovarian cancer (28%) and endometrial cancer (32%). In addition, the increase in breast cancer risk was small and went away in two years or less. In contrast, the decrease in the risk of ovarian and endometrial cancer was large and lifelong; It was directly related to the duration of oral contraceptives and lasted more than 30 years.
“Ovarian cancer is fatal and difficult to treat,” lead study author Åsa Johansson told the New York Times. “The death rate for breast cancer is lower. If you have a close relative who has died from ovarian cancer, then you can make a decision about oral contraceptives. If you have one that died of breast cancer, you could do another. “
The researchers hypothesized that the observed differences in cancer risk between users and never users are due to fluctuations in hormonal exposure. Hormones like estrogen and progesterone, which for many years may promote breast cancer and reproductive cancer by promoting cell growth and development, multiply during ovulation. Birth control prevents ovulation.
See “Oral Contraceptive Use Not Associated with Long-Term Cancer Risk” for more information. For more information on endometrial cancer, see “Increasing Incidence of Endometrial Cancer Worldwide”.