Frequent Aspirin Use Is Linked to Lower Ovarian Cancer Risk

Frequent aspirin use has been associated with a lower risk of ovarian cancer for several years. New research shows that aspirin may provide protection from the disease regardless of risk factors.

Ovarian cancer is the fifth deadliest cancer for women in the United States. Almost 20,000 new cases are expected to be diagnosed in 2022, according to the American Cancer Society.

The aspirin and ovarian cancer connection

A July 2022 study published in the Journal of Clinical Oncology set out to determine if the link between aspirin and ovarian cancer is modified by established ovarian cancer risk factors. The study was the largest to date on this association and analyzed combined data from 17 study populations and more than 8,300 ovarian cancer cases.

"Our study found that frequent aspirin use is associated with reduced ovarian cancer risk and that other ovarian cancer risk factors do not modify the protective association," said Britton Trabert, Ph.D., M.S., an assistant professor in the obstetrics and gynecology department at the University of Utah School of Medicine and one of the lead researchers on the study.

"Previous studies found that frequent aspirin use was associated with lower ovarian cancer risk, but it was unknown if this risk reduction was the same for all women or if certain subgroups of women might benefit more or less," she continued. "We investigated whether the association between frequent aspirin use and reduced ovarian cancer risk was modified by other established ovarian cancer risk factors."

Ovarian cancer risk factors

Researchers studied the effect of aspirin use on the following ovarian cancer risk factors:

• Endometriosis
• Obesity
• Family history of breast or ovarian cancer
• Pregnancy
• Oral contraceptive use
• Tubal ligation (female sterilization)

The study found the association between frequent aspirin use and ovarian cancer risk was not affected by other ovarian cancer risk factors.

Research findings

Aspirin use was associated with a 13 percent overall reduction in ovarian cancer risk. Among women with two or more risk factors, frequent aspirin use was associated with a 19 percent reduction in ovarian cancer risk.

"Given that ovarian cancer is a rare malignancy, any interventions to reduce ovarian cancer risk may be most effective if targeted to women with a higher baseline ovarian cancer risk," Trabert said. "Women with these ovarian cancer risk factors may also potentially benefit from frequent aspirin use for ovarian cancer prevention."

However, the study found no association between aspirin use and a reduced risk of ovarian cancer in women with endometriosis.

"The inverse association could be due to several reasons," Trabert explained. "First, the lack of an association may be due to the small number of women with endometriosis and the limited power to detect associations within this subgroup. Second, we might not be capturing the appropriate time window of aspirin exposure to demonstrate a benefit in terms of preventing ovarian cancer among women with endometriosis."

The study mostly measured the use of aspirin among peri- and postmenopausal women. That's not during the period when endometriosis is likely to be developing and/or proliferating.

Next steps in the research

Thanks to these findings, Trabert and her colleagues will continue to focus on the specific patterns of aspirin use for ovarian cancer prevention.

"It remains unclear whether the dose of aspirin or the age at first use influences the observed protective associations," she explained. "The duration of use needed to observe potential benefits is also unknown. We are also researching to understand the potential biological mechanisms through which aspirin may prevent ovarian cancer. Addressing these questions will help to pinpoint more precisely how frequent aspirin use may play a role in ovarian cancer prevention."