HRT and ovarian cancer: Is there a link?

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The potential link between HRT and ovarian cancer remains a topic of ongoing investigation. At present, scientists have not established that HRT is a direct cause of ovarian cancer. However, some studies have found a correlation.

A 2019 analysis of previous research found evidence that combined HRT and estrogen-only HRT may increase the risk of ovarian cancer. This risk may differ across different subtypes of ovarian cancer, with types known as serous and endometrioid having the strongest association.

That said, this research only suggests an association, not that HRT directly causes these cancers. At present, it is unclear what factors could be contributing to the apparent link.

For example, it could be that the type or duration of HRT use influences the risk. A person’s individual medical history and genetics could also play a role.

Additionally, not all studies have found a significant association between all types of HRT and ovarian cancer. Some have found little evidence of any link.

Because the nature of the association between HRT and ovarian cancer is currently unclear, there is no way of knowing how significant any risk may be.

A 2023 study followed 75,606 females in France through postmenopause and found that:

• people who had HRT containing both estrogens and progesterone or dydrogesterone had a slightly higher risk of ovarian cancer (1.28 times higher) compared with those who never used hormone therapy
• people who used HRT with estrogens and other progestogens had a slightly lower risk of ovarian cancer (0.81 times lower) compared with those who never used hormone therapy
• the use of estrogen alone had a risk that was not significantly different from those who never used hormone therapy (1.09 times higher)

More research is necessary to determine if HRT directly raises the risk of ovarian cancer and if so, by how much.

Many factors can contribute to a person’s risk of developing ovarian cancer, including:

• Age: Ovarian cancer becomes more common with age. Around 50% of all ovarian cancers occur in people ages 63 and older.
• Pregnancy: Having a first full-term pregnancy after age 35 or never having a full-term pregnancy increases the risk of ovarian cancer.
• Family history: A family history of ovarian cancer, colorectal cancer, or breast cancer may indicate a person has a higher risk of developing ovarian cancer. This is because all of these cancers can have links to certain genes that run in families.
• Family cancer syndromes: This is when many people in a family carry genes that significantly increase the risk of a certain cancer. Many people in a single family may get this cancer, or it may occur in members of the family at a younger age than is typical. Only around 5–10% of all cancer cases occur due to family syndromes, but the rate for ovarian cancer is higher, at up to 25%.
• Previous breast cancer: Some of the risk factors for breast cancer and ovarian cancer are the same. If a person has previously had breast cancer, they may have a higher risk of ovarian cancer than other people.
• Smoking: Smoking can increase the risk of a specific type of ovarian cancer known as mucinous ovarian cancer.

There is also a possible link between obesity and a higher risk of ovarian cancer. However, more research is necessary to understand the relationship.

Having pregnancies before the age of 26, breastfeeding, and using birth control pills may lower the risk.

The decision to go through menopause without HRT is a highly personal one.

While HRT may increase ovarian cancer risk, it also offers substantial benefits. These could include:

• relief from menopausal symptoms
• protection against osteoporosis
• potential reductions in the risk of colorectal cancer and heart conditions

It may be best for people to speak with a knowledgable healthcare professional when making the decision about whether to use HRT or not.

It is important that they take into account their circumstances and health goals, including the following factors:

• their personal health history
• the severity of their menopause symptoms
• their family history of medical conditions
• the presence of risk factors for conditions that may improve or worsen with HRT

People who already have ovarian cancer or have had it in the past face unique challenges when considering HRT. Some doctors may recommend avoiding it, as the hormones in HRT can influence some types of ovarian cancer.

For example, ovarian tumors can have hormone receptors, such as estrogen receptors. Doctors refer to tumors with estrogen receptors as estrogen-receptor positive (ER+). Taking more estrogen can promote the growth and spread of this type of cancer.

Some experts may therefore not deem HRT appropriate for people with a history of ovarian cancer.

However, an older 2015 study suggests some people with severe menopause symptoms following ovarian cancer treatment can safely take HRT. Furthermore, the study authors state that the therapy may benefit these people in terms of life expectancy and quality of life.

There are still conflicting opinions surrounding HRT and the risk of ovarian and other cancers. Cancers vary considerably in how they develop, so HRT can affect them very differently.

People who have had cancer can consult a doctor to decide if HRT may be beneficial for them.

People who are considering HRT and have concerns about the potential risks can have an open discussion with a doctor.

Here are some questions people may want to ask:

• Do I have risk factors for ovarian cancer?
• Is HRT safe or suitable for me?
• Can you explain the potential benefits and risks of HRT?
• As a person who has had cancer, how will HRT affect my cancer risk?
• Are there specific tests or evaluations to determine my suitability for HRT?
• Can you tell me about the latest research or guidelines on HRT and cancer risk?
• Are there nonhormonal alternatives for managing my symptoms?
• Is there a duration limit for HRT use?

HRT offers a range of potential benefits for those experiencing menopause symptoms. However, some evidence suggests it could increase ovarian cancer risk. The extent of this risk is unclear, but one study suggests certain types may have a higher level of risk than others.

It is important that anyone contemplating HRT discusses the possible benefits and risks with a doctor. The decision to begin treatment will need to take into account factors such as the person’s medical and family history and the severity of their symptoms.