Magee-Womens Research Institute & Foundation

Apr 7, 2020

Pittsburgh, PA – Breastfeeding is associated with a significant decrease in ovarian cancer risk, including the most lethal type of the disease, a new study from Magee-Womens Research Institute (MWRI) and Brigham and Women’s Hospital finds. The study is online in this week’s JAMA Oncology.

This is the largest study to date of breastfeeding and ovarian cancer risk, including 9,973 women with ovarian cancer from 13 research studies around the world. A history of breastfeeding was associated with a 24 percent decrease in cancer risk, and even breastfeeding one child for a few months may be beneficial in reducing ovarian cancer risk.

“Right now, we don’t have screening for ovarian cancer – there isn’t the equivalent of the mammogram for breast cancer detection. When ovarian cancer symptoms present, the cancer is often advanced. My colleagues and I wanted to explore the protection breastfeeding, as a modifiable lifestyle behavior, could provide. We were especially excited to learn that even breastfeeding for a few months was associated with reduced ovarian cancer risk and that this protection lasted more than 30 years,” said Francesmary Modugno, Ph.D., a principal investigator with MWRI and co-senior author on the study.

For the study, Dr. Modugno and colleagues analyzed data from 13 studies that were a part of the international Ovarian Cancer Association Consortium. The studies were population-based and the majority used in-person interviews for data collection – two utilized written questionnaires. Detailed information on breastfeeding history, including breastfeeding duration and age of each breastfeeding episode, was collected and analyzed using statistical models that took into account potential factors such as number of children and oral contraceptive use, which could obscure any relationship between breastfeeding and ovarian cancer.

“The five-year survival rate for women with the most-deadly type of ovarian cancer – high grade serous cancer – is maybe 30 percent, and these cases often relapse within two years. We know that childbearing and oral contraceptive use are modifiable behaviors that reduce ovarian cancer risk – what this study shows is, across a wide range of diversity and geography – breastfeeding offers protection in addition to the protection pregnancy provides,” said Dr. Modugno.

This study adds to the growing list of known health benefits of breastfeeding for women. “My colleagues and I are hopeful that these findings will provide additional encouragement for policy makers and employers to create supportive environments for women who choose to breastfeed,” Dr. Modugno added.

Additional contributors to the study include researchers at Brigham and Women’s Hospital , Dana Farber Cancer Institute, Moffit Cancer Center, QIMR Berghofer Medical Research Institute (Australia), the University of Queensland (Australia), Yale University, Fred Hutchinson Cancer Institute, University of Utah, German Cancer Research Center, University Medical Center Hamburg-Eppendorf (Germany), Cedars-Sinai Medical Center, Roswell Park Cancer Institute, Danish Cancer Society Research Center (Denmark), Dartmouth University, Emory University, Rutgers Cancer Institute, Icahn School of Medicine at Mount Sinai, Stanford University, University of South Florida, University of Michigan, University of Southern California, Memorial Sloan Kettering

This research was supported by the National Cancer Institute.