Causes, Risk Factors, and Screening for Ovarian Cancer

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We aren't certain exactly what causes ovarian cancer, but hormonal, genetic, and lifestyle risk factors may all play a role. It's thought that most of these cancers are related to a combination of factors, so being aware of your personal risk may help you make lifestyle changes that can reduce your risk.

Common Risk Factors

Cancer begins after a series of mutations in the genetic material (DNA) of cancer cells leads them to grow in an out-of-control fashion, seemingly immortal.


A number of theories have been proposed. It appears that inflammation is important in the development of cancers, and risk factors for ovarian cancer support this. We know that genetics play a role as well, and a family history of the disease or known BRCA mutations significantly increase the risk.

It's important when discussing risk factors, however, to note an important concern in statistics. Just because two things are correlated, does not mean that there is causation. There are more drownings in the summer and people eat more ice cream in the summer, but this does not mean that eating ice cream causes drownings. This is an important distinction to make when looking at potential causes and thinking about ways to reduce your risk.

Having a risk factor for ovarian cancer does not mean that you will develop the disease, even if your risk is high, such as with BRCA gene mutations. It is usually a combination of factors that lead to the development of cancer.

Likewise, many people who develop ovarian cancer do not have any of the known risk factors.


Hormonal Risk Factors

Hormonal risk factors are important in the development of ovarian cancer, and some medications and procedures can either increase or decrease your risk. Ovarian cancer is more common in postmenopausal women as the risk of the disease increases with age.

Estrogen therapy may increase or decrease the risk of ovarian cancer, depending on the type.  Hormone replacement therapy (HRT) may increase your risk of ovarian cancer, but only if you take estrogen-only medications. Combined estrogen/progesterone HRT does not appear to raise the risk. Taking oral contraceptives (the birth control pill), in contrast, reduces the risk up to 50 percent, with longer duration of use correlated with greater reduction. This risk reduction continues for at least 30 years after discontinuing the pill. The birth control shot (Depo-Provera) is also associated with a lower risk. It's not certain at this time if fertility drugs (such as Clomid) raise the risk, though a history of infertility is associated with a higher risk. Studies looking at fertility drugs and ovarian cancer did not see an increase in the risk of epithelial ovarian tumors, but rather the less common (and usually much less aggressive) stromal cell tumors.

Women who have a child before the age of 26 have a lower risk of developing ovarian cancer, as do those who breastfeed. Having a first child over the age of 35, however, is linked with a slightly elevated risk. Late menopause is also associated with a higher risk.

Since several of these factors are associated with reduced ovulation, it could be that a greater number of ovulatory cycles plays a role in the development of these cancers. Ovulation does cause inflammation, and inflammation is associated with cancer, but the precise mechanism is still unknown.

Tubal ligation surgery can significantly reduce the risk of ovarian cancer by up to 70 percent in some studies, though the mechanisms for this are unclear. Having a hysterectomy reduces the risk by around one-third. Endometriosis, a condition in which uterine (endometrial) tissue grows outside of the uterus, is linked with a greater risk of ovarian cancer.


If you've watched the news and discussions about BRCA mutations, you probably realize that ovarian cancer can be hereditary. Yet in this day and age when gene testing is so new, it's important to talk about the difference between having a family history of cancer and having a known genetic mutation. Having a  genetic predisposition to cancer does not mean that you will develop the disease, even if you carry a genetic mutation.

Family History

Understanding hereditary cancer is very confusing. Many people have a family history of ovarian cancer (or breast cancer) but test negative on the BRCA gene tests. There are a few reasons for this. One is that BRCA tests do not usually test for all potential mutations. There are a few hundred different types of BRCA gene mutations, and the newly available do-it-yourself gene tests only check for a few of these. In addition, there are a number of genes which increase the risk of ovarian cancer, only one of which is the BRCA gene.

For women who have a family history of ovarian cancer, their risk is increased (even in the setting of negative BRCA mutation testing). An increased risk may come equally from either side of the family, so a history of ovarian cancer on either your mother or father's side should be noted. The risk is highest for those who have a first-degree relative who has had the disease, such as a mother, sister, or daughter. Having more than one relative with the disease raises the risk further. 

Women who have a family member who has or had ovarian cancer and a BRCA gene mutation, but test negative themselves, still have an increased risk of ovarian cancer. Women who have a personal history of breast cancer also have an increased risk of developing ovarian cancer, even if they test negative for BRCA mutations. If you suspect that BRCA gene mutations run in your family, talk to your doctor about who should have BRCA testing, but keep in mind that your risk could still be elevated even if the test is normal.

At the current time, there are likely many gene changes that confer an increased risk that have not yet been discovered. For those who are concerned, seeing a genetic counselor is important. A genetic counselor can look at patterns in the family, including the presence of other cancers which may be associated with an increased risk of ovarian cancer (such as breast cancer, colon cancer, pancreatic cancer, prostate cancer, and more). In fact, some people may be deemed to have a higher risk of ovarian cancer based on their family history than those who have a known mutation.

Family Cancer Syndromes

Up to 10 percent of ovarian cancers are related to one of the cancer family syndromes in which a specific gene mutation is present. Many of these syndromes are related to mutations in what are known as tumor suppressor genes. These are genes that code for proteins that repair damaged DNA in cells. These include:

  • BRCA gene mutations: Having a BRCA gene mutation significantly increases the risk of ovarian cancer, with around 40 percent of women with BRCA1 mutations and 20 percent with BRCA2 mutations expected to develop ovarian cancer in their lifetime. Ovarian cancer also tends to occur at an earlier age than it does in those without the mutation, and these cancers tend to be more aggressive as well. We don't currently have any guidelines for screening women with these mutations. Some physicians recommend screening with transvaginal ultrasounds and CA-125 blood tests, though screening has not been found to reduce the death rate. Removal of the tubes and ovaries (salpingo-oophorectomy) does reduce the risk by 75 to 90 percent.
  • Lynch syndrome (hereditary non-polyposis colon cancer or HNPCC): Women with HNPCC have roughly a 10 percent chance of developing ovarian cancer (along with a very high risk of developing colon cancer and a moderate risk of uterine cancer). There are several different genes which may be mutated in this syndrome.
  • Peutz-Jeghers syndrome: This syndrome is related to mutations in the gene STK11 and is associated with an increased risk of ovarian cancer. It also is linked with the formation of colon polyps and an increased risk of several digestive tract cancers.
  • Cowden disease (tumor hamartoma syndrome): Cowden disease is a condition related to a mutation in the PTEN gene. It increases the risk of benign tumors called hamartomas, as well as ovarian cancer, breast cancer, and thyroid cancer.


For unknown reasons, women who are tall (over 5 feet 8 inches) are more likely to develop ovarian cancer than shorter women. It's not known if this is related to height, or if height, as ovarian cancer risk, simply runs in families.

Lifestyle Risk Factors

Lifestyle factors may play role in the development of ovarian cancer, and many of these (unlike your family history) can be modified or controlled. These include:


Obesity is linked to an increased risk of low-grade serous and invasive mucinous tumors (types of epithelial ovarian cancer) but does not appear to increase the risk of high-grade invasive serous cancers. Obesity also appears to be associated more with premenopausal than postmenopausal cancers.

There are several mechanisms that have been proposed. One is the increase in estrogen associated with obesity (fatty tissue produces androgens which are converted to estrogens). In addition, obesity often causes the body to have increased levels of insulin and a related factor known as insulin-like growth factor-1 (IGF-1), that, in addition to its normal physiologic functions of stimulating growth during childhood and helping to repair and build muscle tissue in adulthood, may promote the development and growth of certain tumors, particularly when it is present at higher-than-normal levels, as it is in obesity. Obesity also increases inflammation, which has been associated with an increased risk of cancer.

Unfortunately, women who are obese or overweight are also at a greater risk of dying from the disease when present. Fortunately, losing only 5 pounds to 10 pounds may reduce your risk.

Talc Use

The use of feminine sprays and powders containing talc has been linked to ovarian cancer. Fortunately, it is fairly easy to eliminate this risk factor.


A few studies have found that a low-fat diet is associated with a lower risk of ovarian cancer, but overall there has been little evidence that diet plays a significant role.

Of interest for those who are attempting to reduce their risk factors, turmeric or curcumin, a common ingredient in curry, has been associated with a lower risk of ovarian cancer both in population studies and studies in the lab. While the research is still too early to make any recommendations, if you enjoy eating curry, don't stop.


Smoking is linked to one type of ovarian cancer: mucinous epithelial tumors. Yet due to the large numbers of cancers caused by smoking, quitting if you smoke is simply a good idea.


At the current time, screening is not recommended for people who have an average risk of developing ovarian cancer. It's felt that the risks of screening tests (such as unnecessary surgery) outweigh the possible benefits. It's important to note that screening is defined as testing for a disease when no symptoms are present. If you have any symptoms of ovarian cancer (and they can be subtle and vague in the early stages) an evaluation of those symptoms would not be considered screening, but rather, diagnostic.

For those who have an elevated risk, some physicians have recommended twice yearly transvaginal ultrasounds and CA-125 blood tests beginning at age 35, or at an age 10 years younger than when a relative developed the disease. Unfortunately, this type of screening, even in those who carry BRCA gene mutations, has not been found to reduce the risk of death from the disease.


Henderson, J., Webber, E., and G. Sawaya. Screening for Ovarian Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2018. 319(6):595-606.

National Cancer Institute. BRCA Mutations: Cancer Risk and Genetic Testing. Updated 01/30/18.

National Cancer Institute. Ovarian Epithelial, Fallopian Tube, and Primary Peritoneal Cancer Treatment (PDQ)—Health Professional Version. Updated 01/19/18.

Seo, J., Kim, B., Dhanasekaran, D., Tsang, B., and Y. Song. Curcumin Induces Apoptosis by Inhibiting Sarco/Endoplasmic Reticulum Ca2+ ATPase Activity in Ovarian Cancer Cells. Cancer Letters. 2016. 371(1):30-7.

Tworoger, S., and T. Huang. Obesity and Ovarian Cancer. Obesity and Ovarian Cancer. 2016. 208:155-176.