What to know about family history and ovarian cancer

Cancer experts have long known that having a close blood relative—such as a parent or sibling—with a certain type of cancer raises your risk for developing the same disease.

But the risk may reach even further. In some cases, a family history of one cancer may raise the chances of developing a different cancer—one that doesn't seem directly related.

This connection is especially important for ovarian cancer.

The family-cancer connection

Having a family history of ovarian cancer, especially if your mother or sisters were diagnosed, increases your chances of developing the disease. A family history of other forms of cancer—particularly breast, uterine, prostate, or colorectal cancer—can also raise ovarian cancer risk.

One reason is that certain genes influence multiple types of cancer. That means if multiple family members share a genetic variation, it could increase the risk of more than one type of cancer. For ovarian cancer in particular, it’s believed that up to 25 percent of cases may be linked to genetics.

For example, mutations in the breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2) raise the risk for breast cancer and account for most inherited ovarian cancers. A mutation in the BRCA1 gene may raise lifetime ovarian cancer risk 35 to 70 percent. (In other words, for every 100 people who have a BRCA1 mutation, up to 70 of them may be diagnosed with ovarian cancer.) For the BRCA2 mutation, risk is believed to be between 10 to 30 percent by age 70. Mutations in several other genes are also linked to a higher risk of ovarian cancer.

These statistics highlight why it’s so important to understand your family cancer history and share that information with a healthcare provider (HCP).

How to take action

If you have a family history of cancer, these strategies may help to reduce your risk of developing the disease or help to catch it early.

Keep a personal health record

A personal health record is a current, self-maintained collection of your medical information, including your family cancer history. This history should include blood relatives including your parents, grandparents, aunts, uncles, siblings, children, nieces, and nephews. For each family member, note the types of cancer they have or had, the age at which they were diagnosed, and the age they died.

It’s important to be thorough, since the links between some cancers may not be obvious. For example, studies show a link between ovarian cancer and having a father or sibling with prostate cancer.

Consider getting tested

The National Comprehensive Cancer Network recommends genetic testing for anyone diagnosed with ovarian cancer, regardless of family history. This testing can determine if a genetic mutation contributed to the cancer. If a mutation is detected, other family members should be informed so that they can discuss testing with their HCPs.

Likewise, you may want to consider genetic testing if your family history suggests that a close relative has a high risk of inherited ovarian cancer, or cancer that is passed down through families. A genetic counselor or other HCP with experience in assessing genetic risk can guide you.

People who test positive for genetic mutations and are at high risk for ovarian cancer may consider having their ovaries and fallopian tubes (tubes connecting the ovaries to the uterus) surgically removed. This can significantly lower the risk of ovarian cancer, but it doesn’t eliminate it entirely. It comes with its own complications, as well, including premature menopause (complete cessation of the menstrual cycle) and fertility loss.

If you have questions about genetic testing for cancer and what your insurance covers, speak with your HCP.

Understand additional risk factors

It’s important to understand the risk factors for ovarian cancer aside from a family history and certain genetic mutations. Getting older is one factor; the risk of ovarian cancer increases as you age. Others include:

• Having a personal history of breast or ovarian cancer
• Having endometriosis
• Being obese
• Becoming pregnant and having a child later in life
• Being on estrogen-only hormone replacement therapy longer than five years

Make prevention a priority

These actions may help to lower the risk of ovarian cancer.

• If you smoke, quit. Smoking can cause cancer almost anywhere in your body. Quitting is one of the most powerful things you can do to prevent cancer.
• Research suggests that birth control pill use may lower ovarian cancer risk for people at average risk and for those with BRCA mutations. However, taking the pill has its own set of risks, so speak with an HCP.
• Childbirth and breastfeeding may also lower the risk of ovarian cancer, though experts do not recommend having a child for the purpose of ovarian cancer prevention.
• Certain gynecologic surgeries performed for medical reasons may also reduce ovarian cancer risk. These include tubal ligation (fallopian tubes are cut or blocked to prevent pregnancy) and hysterectomy (surgical removal of the uterus).

Key points

Knowing your family history is a powerful tool in understanding your cancer risk. While it may feel uncomfortable to confront, this knowledge can help you get diagnosed earlier, when treatment may be more effective and more options are available.