TAMPA, Fla. and BOSTON — Women who have experienced six or more symptoms of post-traumatic stress disorder (PTSD) had double the risk of developing ovarian cancer compared with women who never had any PTSD symptoms, according to a new study from researchers at Moffitt Cancer Center and Harvard T.H. Chan School of Public Health.
The findings indicate that having higher levels of PTSD symptoms, such as being easily startled by ordinary noises or avoiding reminders of the traumatic experience, can be associated with increased risks of ovarian cancer even decades after experiencing a traumatic event. The study also found that the link between PTSD and ovarian cancer remained for the most aggressive forms of ovarian cancer.
The findings were published today in Cancer Research.
“In light of these findings, we need to understand whether successful treatment of PTSD would reduce this risk, and whether other types of stress are also risk factors for ovarian cancer,” said co-author Andrea Roberts, Ph.D., MPH, research scientist at Harvard T.H. Chan School of Public Health.
Ovarian cancer is the deadliest gynecologic cancer and the fifth most common cause of cancer-related deaths among U.S. women. Studies in animal models have shown that stress and stress hormones can accelerate ovarian tumor growth, and that chronic stress can result in larger and more invasive tumors. A prior study found an association between PTSD and ovarian cancer in humans, but the study included only seven women with ovarian cancer and PTSD.
“Ovarian cancer has been called a ‘silent killer’ because it is difficult to detect in its early stages; therefore identifying more specifically who may be at increased risk for developing the disease is important for prevention or earlier treatment,” said co-author Laura Kubzansky, Ph.D., Lee Kum Kee Professor of Social and Behavioral Sciences at Harvard Chan School.
To better understand how PTSD may influence ovarian cancer risk, researchers analyzed data from the Nurses’ Health Study II, which tracked the health of tens of thousands of women between 1989 and 2015 through biennial questionnaires and medical records. Participants were asked about ovarian cancer diagnosis on each questionnaire, and information was validated through a review of medical records.
In 2008, 54,763 Nurses’ Health Study II participants responded to a supplemental questionnaire focused on lifetime traumatic events and symptoms associated with those events. Women were asked to identify the event they considered the most stressful, and the year of this event. They were also asked about seven PTSD symptoms they may have experienced related to the most stressful event.
Based on the responses, women were divided into six groups: no trauma exposure; trauma and no PTSD symptoms; trauma and 1 to 3 symptoms; trauma and 4 to 5 symptoms; trauma and 6 to 7 symptoms; and trauma, but PTSD symptoms unknown.
After adjusting for various factors associated with ovarian cancer, including oral contraceptive use and smoking, the researchers found that women who experienced 6 to 7 symptoms associated with PTSD were at a significantly higher risk for ovarian cancer than women who had never been exposed to trauma. Women with trauma and 4 to 5 symptoms were also at an elevated risk, but the risk did not reach statistical significance.
The study also showed that women who experienced 6 to 7 symptoms associated with PTSD were at a significantly higher risk of developing the high-grade serous histotype of ovarian cancer — the most common and aggressive form of the disease.
“Ovarian cancer has relatively few known risk factors — PTSD and other forms of distress, like depression, may represent a novel direction in ovarian cancer prevention research,” said Shelley Tworoger, Ph.D., associate center director of Population Science at Moffitt. “If confirmed in other populations, this could be one factor that doctors could consider when determining if a woman is at high risk of ovarian cancer in the future.”
Other Harvard Chan School researchers who contributed to the study included Karestan Koenen and Yongjoo Kim. Tianyi Huang of Brigham and Women’s Hospital and Harvard Medical School was also a co-author.
Funding for this study came from a Department of Defense (W81XWH-17-1-0153) grant.
About Moffitt Cancer Center
Moffitt is dedicated to one lifesaving mission: to contribute to the prevention and cure of cancer. The Tampa-based facility is one of only 51 National Cancer Institute-designated Comprehensive Cancer Centers, a distinction that recognizes Moffitt’s scientific excellence, multidisciplinary research, and robust training and education. Moffitt is a Top 10 cancer hospital and has been nationally ranked by U.S. News & World Report since 1999. Moffitt devotes more than 2 million square feet to research and patient care. Moffitt’s expert nursing staff is recognized by the American Nurses Credentialing Center with Magnet® status, its highest distinction. With more than 6,000 team members, Moffitt has an economic impact in the state of $2.5 billion. For more information, call 1-888-MOFFITT (1-888-663-3488), visit MOFFITT.org, and follow the momentum on Facebook, Twitter and YouTube.
About Harvard T.H. Chan School of Public Health
Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people’s lives—not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America’s oldest professional training program in public health.