Study: Frequent aspirin use may reduce the risk of ovarian cancer
Aspirin may help lower the risk of ovarian cancer in people who have a high risk of the disease, according to a new analysis of 17 studies. While other preventive strategies have been found to more effectively lower the likelihood of developing ovarian cancer in high-risk women, taking aspirin daily or almost daily may reduce a person’s risk of developing ovarian cancer by 13 percent. The benefit was greater among people with additional risk factors for the disease. (Posted 2/22/23)
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Most relevant for: Healthy people at high-risk of ovarian cancer.. It may also be relevant for:
- people with a genetic mutation linked to cancer risk
- people with a family history of cancer
Strength of Science: Medium-High
Research Timeline: Post Approval
What is this study about?
This study looks at whether people with an increased risk of ovarian cancer benefit from frequent aspirin use.
Why is this study important?
Ovarian cancer is the fifth leading cause of cancer deaths among women. Even though it is less common than many other cancers, no screening test is available for the general population, and ovarian cancer is often detected at later stages when it is harder to treat. Prevention efforts focus on increasing awareness of warning signs and risk factors. Risk-reducing removal of the ovaries and (salpingo-oophorectomy) is an option for carriers of inherited mutations such as that increase the risk of ovarian cancer. Oral contraceptives may lower the risk of ovarian cancer by up to 50 percent. Researchers have been interested in evaluating additional risk-reducing options.
Prior research found that taking aspirin may protect against ovarian cancer (see our previous reviews here). Yet, the risks of regular aspirin use are significant enough—daily use increases the risk of internal bleeding or stroke—that doctors do not recommend it as a preventive strategy for the general population. The U.S. Preventive Services Task Force no longer recommends daily aspirin to prevent heart disease for most people. When doctors have recommended aspirin for prevention, it has usually been in a lower dose (once called “baby aspirin”), which is linked to bleeding but not stroke. Low-dose is 81 mg of aspirin, compared to a full dose of 325 mg. Low-dose and full-dose aspirin are available without a prescription.
This study seeks to determine whether the benefit of taking aspirin outweighs the risks for people at high risk of ovarian cancer. The findings from this research could offer a new option to help prevent this disease in this population.
The study team analyzed data from 17 studies to better understand the relationship between aspirin use and ovarian cancer. They sought to determine whether taking aspirin frequently could help lower the risk of ovarian cancer and whether it was effective for people with specific risk factors.
The researchers looked at factors that increase the risk of ovarian cancer, such as a family history of breast or ovarian cancer, endometriosis and obesity, as well as some factors that reduce risk, including past pregnancies, use of birth control pills and tubal ligation. (Never having given birth, no use of oral contraceptives and no tubal ligation are factors that may contribute to risk.) Researchers then calculated an overall ovarian cancer risk score for each person based on these factors.
Frequent aspirin use was defined as taking aspirin six or more days each week or 28 or more days each month for at least six months. Participants self-reported their use. Women were followed for 4 to 14 years in the studies that reported follow-up.
Researchers found that:
- people who take aspirin frequently have a 13% reduced risk of developing ovarian cancer.
- the benefit was even greater (19% reduction in risk) among people with two or more risk factors for ovarian cancer including endometriosis, obesity, not bearing children, family history of breast or ovarian cancer, no oral contraceptive use, and no tubal ligation.
What does this mean for me?
If you have a higher-than-average risk of ovarian cancer and you are interested in taking aspirin as a means of lowering your risk, talk with your doctor about this study. Frequent aspirin use can increase the risk of bleeding so it is important to weigh the risks and benefits before starting to take aspirin. Depending on your risk profile, daily use may cause more harm than good.
Additionally, the study results suggest that people with endometriosis did not benefit from aspirin use. However, there was some evidence of possible risk reduction specifically for endometrioid ovarian cancer. More research is needed to validate or refute this.
This study did not address an increased risk of ovarian cancer due to genetic mutations such as , or because the research team did not know the participants' mutation status. It is not clear whether some of the people in the study who reported a family history of breast or ovarian cancer had an , and therefore whether people with inherited mutations would benefit from aspirin. Other risk-reducing strategies may offer greater benefits, such as risk-reducing surgery or oral contraceptive use (more in our XRAY review).
This study suggests that taking daily aspirin may modestly reduce ovarian cancer risk but also increase risks of internal bleeding and stroke.
Hurwitz LM, Townsend MK, Jordan SJ, et al., Modification of the association between frequent aspirin use and ovarian cancer risk: A using individual-level data from two ovarian cancer consortia. Journal of Clinical Oncology; 2022; doi: 10.1200/JCO.21.01900. Published online July 22, 2022.
National Cancer Institute. Can taking aspirin help prevent cancer? October 2, 2020
Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.
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Who covered this study?
Daily aspirin use may reduce ovarian cancer risk among high-risk patients This article rates 3.0 out of 5 stars
Cancer Therapy Advisor
Taking aspirin 6-7 days a week may decrease the risk of ovarian cancer This article rates 3.0 out of 5 stars
WPLG Local News 10 (Broward County, FL)
Research continues in low-dose aspirin and ovarian cancer risk reduction This article rates 2.5 out of 5 stars
Meta-analysis examines link between aspirin use and ovarian cancer risk This article rates 2.5 out of 5 stars
IN-DEPTH REVIEW OF RESEARCH
Aspirin has been studied as a form of (medicine taken to prevent disease) for years. Researchers have asked whether aspirin is useful for both heart disease and cancer.
The effects of aspirin on cancer risk are mixed. Some evidence indicates that aspirin can help to prevent colon cancer. In the 2011 CAPP2 study, daily high-dose aspirin reduced colon cancer risk by 63 percent in people with . Follow-up research published in 2020 confirmed this benefit. A 2016 study showed that among people with an average risk of colon cancer, regular use of aspirin reduced their risk of colon cancer by 19 percent and any GI cancer by 15 percent.
Yet the news is not all good. The large 2020 ASPREE trial found that aspirin may cause harm. Participants ages 70 and over who took low-dose aspirin were as likely to develop cancer as those who did not take aspirin; however, their cancer was more likely to be advanced and result in death.
Recent studies also are looking for biomarkers to learn more about who might benefit from taking aspirin.
Researchers of this study wanted to know
The research team wanted to know if there was enough evidence to recommend that people with certain risk factors for ovarian cancer could benefit from taking aspirin daily.
Populations looked at in this study
This study looked at women from 17 studies who were at risk for ovarian cancer. Most were U.S.-based studies but some were conducted in the United Kingdom and Australia. The median age of participants ranged from 46 to 68.2 years in the nine cohort studies examined (see below). The median age of the participants in the case-control studies ranged from 56.2 to 60.7 years. The race or ethnicity of the people in the study samples was not reported.
The 17 studies included nine cohort studies from the Ovarian Cancer Cohort Consortium and eight population-based case-control studies from the Ovarian Cancer Association Consortium.
A cohort study follows a group of people over time. A case-control study compares a study group to a control group. Because these are two different types of data sets, the research team looked at them together and separately. The sample included 2,600 people with ovarian cancer in the cohort studies and 5,726 with ovarian cancer in the case-control studies.
- Overall, aspirin was associated with a 13% reduction of ovarian cancer risk in this study.
- Analysis of the cohort studies found a 10% reduction in risk; the case-control studies revealed a 16% reduction.
- Notably, there was a 14% reduction in the risk of developing hard-to-treat, high-grade serous ovarian cancer.
- The reduction in risk was seen in people who were at higher risk due to obesity or had a family history of breast or ovarian cancer, a lack of oral contraceptive use, no prior pregnancies and no tubal ligation.
- This benefit was seen across the study groups regardless of risk with one exception. Women with endometriosis did not benefit from frequent aspirin use. It is possible that this was due to the relatively small number of people with endometriosis in the sample.
- The risk reduction was seen in both obese and nonobese women who took aspirin frequently. The benefit was numerically slightly higher among obese women (21% compared to 9%) but statistically it was the same. Obesity was defined by body mass index.
- The benefit extended to people with and without a family history of breast or ovarian cancer. The research team was not able to look at specific inherited mutations because they did not know the participants' genetic status.
- In the case-control studies, the investigators found a possible higher benefit of aspirin use as women aged, with the strongest benefit among women ages 70+ (18% reduction in risk). However, they did not find the same difference in the cohort studies.
Strengths and limitations
- Many of the previously established studies, such as the Nurses’ Health Study and the Sister Study, follow large groups of people for many years and use high-quality research methods, which increases confidence in the conclusions. These studies have influenced what we know about healthy diet, exercise, prevention of chronic disease and related issues.
- Scientists and physicians from multiple institutions and specialties were involved in this research, indicating that the results can be generalized to people from different regions.
- Although some studies included participants with a family history of cancer, researchers did not include genetic information on participants such as mutation or status. It is unclear whether people with inherited mutations that increase ovarian cancer risk would also benefit from frequent aspirin use.
- The research team was unable to look only at low-dose aspirin use, which has previously been associated with risk reduction. They noted that people who take aspirin frequently often take a lower dose, according to a correlation observed in prior research.
- The cohort studies were all conducted in the U.S. The case-control studies included participants from the U.S., the United Kingdom and Australia. No other countries were represented.
- The research team did not have data regarding when people in the study started taking aspirin or why.
- The results do not look at risk by race or ethnicity, so it is unclear if different groups would respond similarly.
This study summarizes existing research from 17 studies on frequent aspirin use to prevent ovarian cancer. These study authors focused on the benefit of aspirin for people with certain ovarian cancer risk factors.
Aspirin is studied for ovarian cancer prevention due to the relationship between inflammation and this gynecologic cancer. Aspirin is an anti-inflammatory, and there is evidence that chronic inflammation may contribute to ovarian cancer. This potential relationship was first observed in studies of aspirin to prevent heart disease.
While very serious, ovarian cancer is not common. And despite the possible benefit of taking aspirin, it also has drawbacks, most notably a higher risk of bleeding. For these reasons, doctors do not generally recommend taking aspirin to prevent ovarian cancer.
Yet, this study confirmed a potentially modest benefit of daily aspirin with a stronger reduction of risk for people with two or more risk factors for ovarian cancer. However, this approach needs to be balanced with other strategies to decrease risk, including risk-reducing surgery and oral contraceptive use.
These results confirm that taking aspirin frequently may help to prevent ovarian cancer, even more aggressive types of ovarian cancer. This is the first study to find that the benefit extends to people with specific risk factors.
The reduction in risk was seen in people at higher risk due to obesity, family history of breast or ovarian cancer, lack of oral contraceptive use, no prior pregnancies and no tubal ligation. The research team did not see a reduction in risk among people with endometriosis. Although this study showed the benefit of frequent aspirin use among people with a family history of breast or ovarian cancer, it did not specifically look at people with known mutations or .
Future research is needed to address whether people with different inherited mutations or from varied racial and ethnic backgrounds might benefit from taking aspirin. Additional research is also needed to determine the best dose of aspirin to use in this context.
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The National Comprehensive Cancer Network (NCCN) provides guidelines for management of gynecologic cancer risk in people with and mutations.
- Risk-reducing removal of ovaries and , (known as salpingo-oophorectomy) is recommended between ages 35-40 for and 40-45 for and upon completion of childbearing.
- Research studies show that removing the ovaries can increase survival for women with mutations.
- Women should talk with their doctors about the effects of early menopause and options for managing them.
- Women should talk with their doctors about the risks and benefits of keeping or removing their uterus (hysterectomy), including:
- Women with a mutation have an increased risk for a rare form of aggressive uterine cancer; hysterectomy removes this risk.
- For women considering hormone replacement after surgery, the presence or absence of a uterus can affect the choice of hormones used.
- Estrogen-only hormone replacement is less likely to increase the risk for breast cancer, although it increases the risk for uterine cancer. Women who still have their uterus are typically given hormone replacement with both and progesterone.
- Adding progesterone to hormone replacement can protect against uterine cancer. However, the combination of these hormones may increase the risk for breast cancer more than alone.
- A medical history of fibroids or other uterine or cervical issues may justify a hysterectomy.
- Oral contraceptives (birth control pills) have been shown to lower the risk for ovarian cancer in women with mutations. Research on the effect of oral contraceptives on breast cancer risk has been mixed. Women should discuss the benefits and risks of oral contraceptives for lowering ovarian cancer risk with their doctors.
- Removal of the only () is being studied as an option for lowering risk in high-risk women who are not ready to remove their ovaries. Studies on the effects of are ongoing. At this time whether lowers the risk for ovarian cancer in high-risk women remains unknown.
- Consider enrolling in a research study looking at this procedure to lower cancer risk.
- There are no proven benefits to routine ovarian cancer screening using transvaginal and a blood test. However, some doctors still recommend this screening, starting at ages 30-35.
- Women should be aware of the symptoms of gynecologic cancer and report abnormalities to their doctors.
The National Comprehensive Cancer Network (NCCN) provides the following guidelines for the management of gynecologic cancer risk in people with inherited mutations that are linked to endometrial or ovarian cancer. We recommend that you speak with a genetics expert who can look at your personal and family history of cancer and help you to determine the best risk management plan.
, or mutation
- Recommend risk-reducing salpingo-oophorectomy between the ages of 45-50.
- Be aware of endometrial and ovarian cancer symptoms.
- Consider endometrial biopsy every 1-2 years beginning at ages 30-35.
- For postmenopausal women, consider transvaginal after discussion with your doctor.
- Consider risk-reducing hysterectomy; discuss risk-reducing removal of ovaries and with your doctor (, , and ).
- Discuss the benefits and risks of oral contraceptives.
- Be aware of endometrial cancer symptoms.
- Consider endometrial biopsy every 1-2 years beginning at age 35.
- For postmenopausal women, consider transvaginal after a discussion with your doctor.
- Consider risk-reducing hysterectomy.
The following are studies looking at ovarian cancer screening or prevention.
- NCT04251052: A Study to Compare Two Surgical Procedures in Women with Mutations to Assess Reduced Risk of Ovarian Cancer (SOROCk). This study is looking at whether women with mutations who remove just the can reduce the risk of ovarian cancer nearly as much as women who remove their ovaries and .
- NCT05287451: Risk Reducing With Delayed as an Alternative to Risk- Reducing Salpingo-oophorectomy in High Risk-Women to Assess the Safety of Prevention. This study will look at outcomes in women with , , , and who remove their , followed by removal of their ovaries compared to women who undergo standard-of-care removal of their ovaries and at the same time.
- Validating a Blood Test for Early Ovarian Cancer Detection in High-risk Women and Families: MicroRNA Detection Study (MiDE). The goal of MiDe is to develop a test to detect early-onset ovarian cancer. Currently, no reliable screening or early detection tests are available. Participants can be expected to provide up to 4 tubes of blood every 6 months for up to 5 years. These samples can be collected by mobile phlebotomy all around the US.
- NCT04794322: Developing a Test for the Detection of Ovarian Cancer. This study aims to develop an ovarian cancer early detection test that looks at found in a uterine (womb) washing and proteins found in the blood. Participants will not receive the results of their tests.
Additional clinical trials for ovarian cancer screening and prevention may be found here.