What are the risk factors for ovarian cancer?

Diana Meeks
Diana Meeks on behalf of Sigma Nursing
Family Practitioner

Older age, obesity, infertility, and high fat diet increase your risk of ovarian cancer. Certain medications including danazol, a medication used to treat endometriosis, and clomiphene citrate, a medication used to treat infertility, may also increase your risk. Mutations in BRCA1 and BRCA2, two tumor suppressor genes which prevent abnormal cell growth, predispose you to this form of cancer as well. If you have had multiple pregnancies, or if you take birth control pills, your risk of ovarian cancer is lower.

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

Ovarian cancer is the fifth leading cause of cancer-related deaths among women between the ages of 35 and 74. Due to a lack of effective screening methods, this cancer is discovered in women at advanced stages, which is associated with poor survival. It is vital to reduce your risk by recognizing and changing your risk factors, which include having belly fat. Women who are 25 or more pounds overweight have a higher risk of ovarian cancer. Obese women have a 30% higher risk of ovarian cancer compared to those with a healthy weight.

Furthermore, consuming dairy products also has been shown to increase one’s risk of ovarian cancer. Lactose, found in most dairy food, has been hypothesized to promote cancer growth. Studies have found that people who ate 30 grams of lactose a day increased their ovarian cancer risk by 20%. That’s one glass of milk or one cup of ice cream!

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There are a number of risk factors for ovarian cancer. A woman can be at increased risk for this disease particularly if a "first-degree" relative (a mother, sister or daughter) has or had ovarian, breast or colon cancer. In fact, if a woman has a strong family history of ovarian cancer, she is more likely to develop the disease at an early age (on average, 10 years younger than women without genetic risk factors for the disease).

Other risk factors include:
  • Being of Eastern European Jewish ethnicity (Ashkenazi) if the condition has already affected one or more family members
  • Having a mutation in the BRCA1 or BRCA2 gene; the lifetime risk for a woman with the BRCA1 mutation is between 35% and 70%, and the lifetime risk for a woman with the BRCA2 mutation is between 10% and 30%
  • Having a personal history of breast, endometrial or colon cancer
  • Never having been pregnant
  • A high-fat diet
  • Obesity
Starting your periods at a young age (before age 12) or going through menopause at an older age (after age 50)
Of all risk factors for ovarian cancer, the most significant is a family history of breast and/or ovarian cancer. However, it's important to keep risk factors in perspective. Most women with risk factors for ovarian cancer will never get ovarian cancer. And most women with ovarian cancer do not have any strong risk factors for the disease.

Even with significant risk factors such as family history, the overall chances of getting ovarian cancer are still small. Nonetheless, you should talk to your healthcare professional if you know you have any risk factors.
Dr. David A. Fishman, MD
Gynecologic Oncologist
While the presence of one or more of the following risk factors may increase a woman’s risk for developing ovarian cancer, it does not necessarily mean that she will.
  • a personal history of breast, colon or GU cancer
  • one or more first-degree relatives (mother, sister, daughter) who have ovarian cancer
  • multiple family members with breast and/or ovarian cancer
  • uninterrupted ovulation (infertility, never used birth control pills, or nulliparity)
  • the use of fertility drugs for more than one year
  • age 40 or older (as with most cancers, a woman’s chance of developing ovarian cancer increases with age; the highest risk age group is 70–79 years)

The average woman’s risk for ovarian cancer is low—less than 2%—in the absence of a family history of ovarian or breast cancer. In addition to this family history of cancer, women with certain genetic mutations, including BRCA1, BRCA2, HNPCC mutations are also at increased risk for ovarian cancer.

The exact causes of ovarian cancer are not known. The likelihood of developing the disease may be higher if a woman has one or more of the following ovarian cancer risk factors. However, having risk factors does not mean you will develop the disease.

If you’re worried about ovarian cancer, or have a family history of the disease, talk with your doctor about genetic testing and other steps you can take to monitor or reduce your ovarian cancer risks.
  • Age: Two-thirds of women diagnosed with ovarian cancer are age 55 or older.
  • Family history: Women with a mother, sister, grandmother or aunt who has had ovarian cancer have a higher risk of developing it.
  • Genetic mutations: Some women who develop ovarian cancer have an inherited mutation on one of two genes called breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). Women with the BRCA1 mutation, have a 35 to 70 percent higher risk of ovarian cancer. Women with the BRCA2 mutation have a 10 to 30 percent higher risk. However, the vast majority of women who are diagnosed with ovarian cancer don’t have either mutation. If you are concerned about this risk factor for ovarian cancer, you can discuss getting tested for both of the BRCA mutations with your OB-GYN.
  • Breast, colorectal or endometrial cancer: Women who’ve been diagnosed with one of these cancers have a higher risk of developing ovarian cancer.
  • Childbearing status: Women who have delivered at least one child, especially before age 30, are at a lower risk for developing the disease. The more children a woman has, the more her ovarian cancer risk declines. Women who breastfeed further reduce their risk.
  • Obesity: Women with a body mass index (BMI) of 30 or greater may have a higher risk of developing ovarian cancer.
Some studies suggest there is a link between hormone replacement therapy (HRT) and ovarian cancer. This risk appears to be greatest for women who take estrogen only for more than five years, but more research is needed to confirm the relationship between HRT and ovarian cancer.

NOTE: Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer. Not having risk factors doesn’t mean that you will not get cancer. If you think you may be at risk, you should discuss it with your doctor.
Some of the risk factors for ovarian cancer include:
  • Family history of cancer (hereditary): Having close family members (mother, daughter or sister) who have had ovarian cancer may put you at greater risk. Also, a family history of other cancers, like breast, uterine, colon or rectal cancer may increase your chances of developing ovarian cancer.
  • Personal history of cancer: A history of any cancer puts you at greater risk for developing a new cancer. Having breast, uterine or colorectal cancer may put you at greater risk for developing ovarian cancer because these cancers are all closely related.
  • Being 55 or more years old: As we get older our risk for developing any cancer increases, including our risk for developing ovarian cancer. Most women diagnosed with ovarian cancer are 55 years old and over.
  • Never being pregnant: Older women who have never been pregnant are at increased risk for developing ovarian cancer.
Dr. Sharyn N. Lewin, MD
OBGYN (Obstetrician & Gynecologist)
Besides a strong family (sister, mother or daughter) history of breast or ovarian cancer, there are several medications and medical conditions that are associated with the risk of developing ovarian cancer.

The risk of ovarian cancer rises with age, especially around menopause (after 50), and is more common in those who began menstruating before 12 or who have not been pregnant. Personal history of breast, uterus, colon or rectal cancers as well as endometriosis increase the risk.

Multiple pregnancies, breast feeding, use of birth control pills for over 5 years and hysterectomy/tubal ligation may decrease the risk of  ovarian  cancer.

Factors that increase your risk of ovarian cancer include the following:

  • increasing age
  • having a BRCA mutation
  • having Lynch syndrome
  • infertility
  • having polycystic ovarian syndrome
  • having endometriosis
  • smoking cigarettes
  • having an IUD (slight increase)

You are most likely to have ovarian cancer if you are over age 60. You are also at higher risk if you have not had children, or if you have a family history of ovarian cancer. Although fewer than 0.1% of women have the hereditary ovarian cancer syndrome, for these women, the risk of developing ovarian cancer may be 40%.

Risk factors for ovarian cancer include:
  • Age. The median age of diagnosis is 63.
  • Heredity. A family or personal history of ovarian or breast cancer indicates an increased risk. The presence of mutations in the BRCA1 or BRCA2 genes increases a woman's lifetime risk from 1.4% to 15% or as much as 40%. Another genetic syndrome, hereditary nonpolyposis colon cancer, has also been associated with endometrial and ovarian cancer.
  • Postmenopausal estrogen use. Five or more years of estrogen as postmenopausal hormone therapy, without concurrent use of a progestin, has been shown to increase risk in several large studies.
  • Overweight or obesity. A large observational study indicated that a body mass index (a measure that takes into account both weight and height; see Table 2) of 30 or greater increases the risk of ovarian cancer by 80% in postmenopausal women who have never taken hormones.
  • Factors that reduce risk. Pregnancy, the long-term use of oral contraceptives, tubal ligation, and hysterectomy (without ovary removal) appear to decrease risk for most women.
Dr. Nimesh P. Nagarsheth, MD
Gynecologic Oncologist
While doctors don't know all the risk factors for ovarian cancer, researchers have identified a few. In this video, Nimesh Nagarsheth, MD, a gynecolgic oncologist at The Mount Sinai Medical Center, identifies three major risk factors.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.