Breast Cancer and Ovarian Cancer: Is There A Connection?

You may have heard that breast cancer and ovarian cancer can sometimes run in families. If your mother or sister has been diagnosed with either condition, it’s natural to wonder whether you might also be at higher risk. 

Breast cancer remains the most common cancer among women, while ovarian cancer is often detected at a later stage. Understanding how these two cancers are connected can empower you to make informed choices about your health and take proactive steps towards early detection and prevention.

What are breast cancer and ovarian cancer?

Breast cancer starts when cells in the breast grow out of control. These cells usually form a lump or mass that can be felt during a breast self-examination or seen on a mammogram (breast X-ray).

Ovarian cancer, on the other hand, begins in the ovaries, which are the organs that produce eggs. This type of cancer is harder to detect early because the ovaries are located deep inside the pelvis.

Both breast and ovarian cancer primarily affect women.  While men can also develop breast cancer, such cases are much rarer.

How are breast and ovarian cancer linked?

Breast cancer and ovarian cancer share an important connection through genetics. Some women inherit gene mutations that increase their cancer risk for both diseases.

The most common genetic connection is through the BRCA1 and BRCA2 genes. When these genes function normally, they help prevent cancer by repairing damaged DNA. However, when you inherit damaged BRCA genes, your cells cannot repair DNA damage properly, whichincreases your risk of developing hereditary breast and ovarian cancer.

Women with a BRCA1 mutation have up to a 70% chance of developing breast cancer and a 44% chance of developing ovarian cancer by age 80. If many people in your family have had these cancers, your chances of developing one of these conditions may increase even if no genetic tests have confirmed it.

The hormonal connection also plays a role. Both breast and ovarian tissues react to hormones like oestrogen. Some breast cancers have tumour cells that grow in response to oestrogen, and hormones can also affect ovarian cancer risk.

Are you at higher risk? Signs to watch for

Knowing your risk is important, but you also need to know what symptoms to look out for. 

Shared and different risk factors

Other than symptoms, certain risk factors can increase your chances of getting these cancers. Some factors affect both cancers, while others are specific to just one.

Some factors increase your risk for both cancers:

• Having close relatives with breast or ovarian cancer (your mother, sister, or daughter)

• Having gene mutations like BRCA1 or BRCA2

• Getting older

• Never or late in having children

Factors that mainly increase breast cancer risk:

• Starting your menstrual cycle before age 12

• Going through menopause after age 55

• Dense breast tissue

• Being overweight after menopause

• Alcohol consumption

Factors that mainly increase ovarian cancer:

• Endometriosis

• Having your first child after age 35

• Using fertility treatments

Common signs you should not ignore

Both breast cancer and ovarian cancer can show symptoms early. Many women ignore these signs because they seem minor. 

For breast cancer, watch for:

• A new lump in your breast or armpit

• Swelling in part of your breast

• Skin changes like dimpling

• Liquid coming from your nipple (not breast milk)

• Changes in breast size or shape

For ovarian cancer, watch for:

• Feeling bloated often

• Getting full quickly when you eat

• Pain in your lower abdomen 

• Needing to urinate more often

• Abnormal vaginal bleeding

BRCA genes: Why one test can affect both cancers

You can take a single genetic test to check for BRCA1 and BRCA2 mutations. Some tests also look for other genetic changes using what doctors call a multigene panel. This test helps assess your risk of developing both breast and ovarian cancer. If the test is positive, your doctor can plan early screenings and prevention steps to protect your health.

Genetic testing can also benefit your family members. If you have a BRCA mutation, each of your children has a chance of inheriting it. They can undergo testing as well and take proactive measures if necessary.

You should consider genetic testing if:

• You have breast cancer diagnosed before age 50

• You have had ovarian cancer in the past

• Multiple family members have had breast or ovarian cancer

• You have a family history of male breast cancer

If you have a family history of either cancer, request a consultation with Thomson Medical. Our specialists can discuss your genetic risks and recommend appropriate screening or genetic testing for early detection.

Screening and early detection in Singapore: What works and where to go

Screening helps find cancerous cells before you feel any symptoms. For breast cancer, screening works well. However, detecting ovarian cancer early may require a different approach.

Breast screening: Who should go and how often

Breast screening usually involves having a mammogram. These are X-rays of the breast that can detect changes in your breast tissue. Having a regular mammogram screening gives you the best chance of detecting breast cancer early, even before you feel any lumps. 

If you are at average risk, you should: 

• Start at the age of 40

• Get a mammogram every 1-2 years depending on your age

• Continue after age of 70 if you are healthy

If you have higher genetic risk:

• Start mammogram earlier at age of 30

• Get a mammogram every year

• Check your breasts yourself every month

• Your doctor might add breast MRI (another type of scan)

Ovarian cancer: Why there is no routine screening

Unlike breast cancer, there is currently no reliable routine screening test for ovarian cancer in women at average risk.

Many people believe that a Pap smear can detect ovarian cancer, but this isn’t the case. A Pap smear only checks the cervix for signs of cervical cancer, not the ovaries.

If you are a high-risk woman with BRCA mutations or strong family history of ovarian cancer, you should:

• Get CA-125 blood tests every six months

• Get transvaginal ultrasounds every six months

• Consider surgery to remove your ovaries and fallopian tubes after you finish having children

Having your ovaries and fallopian tubes removed is a major decision that requires careful consideration, but it  can lower your ovarian cancer risk by 96%. It also protects against primary peritoneal cancer, which starts in the lining of your belly. If you have a high risk of ovarian cancer, you may need to speak with your doctor about whether this surgery might be appropriate for you.

Treatment options for breast and ovarian cancer

Treatment depends on the type and stage of cancer, your overall health, and your personal preferences.

For breast cancer:

• Surgery to remove the tumour or the whole breast

• Radiation to kill cancer cells

• Chemotherapy (strong medicine that kills cancer cells)

• Hormone therapy if your cancer grows because of hormones

• Targeted therapy for specific types of cancer

• Immunotherapy to help your body fight cancer

For ovarian cancer:

• Surgery to remove your ovaries, fallopian tubes, and often your uterus

• Chemotherapy after surgery

• PARP inhibitors, which work very well if you have BRCA mutations

How can women reduce their ovarian and breast cancer risk?

While you cannot change your genetics or family history, you can take steps to lower your cancer risk.

For both cancers:

• Keep a healthy weight

• Exercise at least 150 minutes each week (like brisk walking)

• Limit alcohol (no more than one drink daily)

• See a genetic counsellor if cancer runs in your family

• Breastfeed if you can (one year or more helps)

For breast cancer prevention:

• Avoid hormone replacement therapy, or use it for the shortest time possible

• Check your breasts yourself every month

For ovarian cancer prevention:

• Take birth control pills

• If you plan to have children, pregnancy can help lower your risk

• Consider an intrauterine device (IUD)

If you’re concerned about your risk of ovarian or breast cancer,request an appointment with Thomson Medical. Our specialists can assess your family history, recommend suitable gynaecological exams, and guide you on lifestyle or treatment options to help lower your risk.

FAQ

Can men also carry ovarian and breast cancer genes?

Yes. Men can inherit BRCA gene mutations. These mutations raise their risk of male breast cancer, prostate cancer, and pancreatic cancer. Even if men do not develop cancer themselves, they can pass these gene changes to their children. Each child has a 50% chance of inheriting the mutation. Knowing your genetic status helps your whole family take early action.

If I have a BRCA mutation, will I definitely get ovarian and breast cancer?

When should I consider doing genetic testing?

There is no specific age for testing. Most women at average risk do not need genetic testing. However, you should consider it if several close relatives have had breast or ovarian cancer, especially if they were diagnosed young. Testing can guide your screening schedule and help you make decisions about prevention.

Can birth control pills help lower ovarian cancer risk?

Yes. Long-term use of birth control pills (five years or more) can reduce ovarian cancer risk by up to 50%. However, they may slightly increase breast cancer risk. Talk with your doctor about your personal health and family history before deciding.

Should I tell my family if I test positive for a BRCA mutation?

Yes. BRCA mutations are inherited. This means your close relatives (parents, siblings, children) may also carry the gene. Sharing this information allows them to consider genetic testing and start early monitoring if needed.

How fast can ovarian cancer progress?

It depends on the type. Some ovarian cancers grow slowly over several years. Others, especially high-grade types, can grow and spread quickly within months. Once symptoms appear, the cancer may already be at an advanced stage. If you notice symptoms like bloating, pelvic pain, or feeling full quickly that last more than two weeks, see a doctor right away.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice based on your unique situations, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.

References:

Dilawari, A. (2009). Co-existence of breast and ovarian cancers in BRCA germ-line mutation carriers. Ecancermedicalscience, 3. https://doi.org/10.3332/ecancer.2008.109

Evans, D. G. R., Clayton, R., Donnai, P., Shenton, A., & Lalloo, F. (2009). Risk-reducing surgery for ovarian cancer: outcomes in 300 surgeries suggest a low peritoneal primary risk. European Journal of Human Genetics, 17(11), 1381–1385. https://doi.org/10.1038/ejhg.2009.60