Individuals who ovulate for longer over their lifetimes may have a higher risk of developing ovarian cancer, suggesting that suppressing ovulation can lower this risk, according to a new study published by Fu et al in the Journal of the National Cancer Institute. The researchers also offered clues as to how oral contraceptives, pregnancy, and breastfeeding impact the risk of developing ovarian cancer beyond simply suppressing ovulation—and how this link may vary among different ovarian cancer subtypes.
“Ovarian cancer is a highly fatal group of diseases with limited treatment options, so understanding its origins and the factors that contribute to disease development are critical steps in devising prevention approaches and improving women’s health,” explained senior study author Francesmary Modugno, MS, PhD, MPH, Associate Professor of Obstetrics, Gynecology, Reproductive Sciences, and Epidemiology in the Division of Gynecologic Oncology at the University of Pittsburgh School of Medicine as well as at the Magee-Womens Research Institute and the University of Pittsburgh Medical Center Hillman Cancer Center. “Studies like this, where researchers from around the world come together and share their data, are critical to achieving these goals,” she commented.
Study Methods and Results
In the new, international study, researchers analyzed 21,267 female patients with ovarian cancer and 26,204 healthy individuals from 25 studies, and discovered that factors that may reduce the duration of ovulation—such as oral contraceptives, pregnancy, and breastfeeding—were possibly linked to a decreased risk of ovarian cancer. The protective effects of these factors were stronger than expected based on ovulation suppression alone. These findings suggested that the factors may have contributed to cancer risk in other ways—including via altering hormones or inflammation.
The researchers also found important distinctions between different subtypes of ovarian cancer. For example, mucinous tumors were associated with factors that suppressed ovulation, but not with ovulation duration itself—another clue that oral contraceptives, pregnancy, and breastfeeding may affect cancer risk beyond suppressing ovulation.
In contrast, for high-grade serous ovarian cancer, the associations of oral contraceptives, pregnancy, and breastfeeding were as expected and indicated that these factors may contribute to the risk of serous ovarian cancer through ovulation suppression.
“These findings emphasize that ovarian cancer subtypes are different diseases with different causes,” noted Dr. Modugno. “This is important, as it will hopefully encourage scientists to look for new hypotheses as to how these diseases arise and shed new light on how we can prevent them. Right now, treatment options are limited, so preventing ovarian cancer is the best hope we have for saving lives,” she concluded.
Disclosure: For full disclosures of the study authors, visit academic.oup.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.