Understanding ovarian cancer risk factors and ways to reduce your personal risk

Each year around 7,500 people are diagnosed with ovarian cancer in the UK, making it the 6th most common cancer diagnosed in women. 

Whilst it’s not known exactly what causes most ovarian cancers, we do know that some people have a higher risk of developing ovarian cancer than others and that your individual risk will depend on multiple factors, which includes your age, your genetics and your lifestyle.

As is the case with most cancer types, ovarian cancer incidence increases with age, however it is possible to develop ovarian cancer at any age. Ovarian cancer can also run in families which is known as an inherited or hereditary risk.

We spoke to Mr Ahmad Sayasneh, Consultant Gynaecologist at London Bridge Hospital, part of HCA Healthcare UK, to understand more about ovarian cancer risk factors and ways to reduce your personal risk.

Understand cancer risk factors

Firstly, I think it’s important to define what a cancer risk factor is. A risk factor is something which can increase your chance of being diagnosed with cancer, and different cancers have different risk factors associated with them.

Unfortunately, some risk factors like your age and genetics or family history, can’t be changed. Whereas other, lifestyle risk factors like smoking, can be changed.

It’s important to understand that risk factors increase your chance of being diagnosed with cancer but they do not mean that you will be diagnosed with cancer. Many people with a known risk factor or multiple risk factors do not develop cancer, in the same way that a person with no known risk factors may be diagnosed with cancer. Risk factors are just one contributing factor to a cancer diagnosis, but understanding your own personal risk factors can help you be more aware and proactively manage them.

Ovarian cancer risk factors

Increasing age

There are several known risk factors that may increase your risk of developing ovarian cancer but increasing age is the biggest risk factor. Over 50% of ovarian cancer diagnoses are in people aged over 65 plus and incidence is highest in people aged 75 to 79. Ovarian cancer is rarer in people under 30 but it is still possible to be diagnosed with ovarian cancer at any age.

Some ovarian tumours, around 15 out of 100, are called borderline tumours. These tumours are most common in younger women aged between 20 and 40. Borderline ovarian tumours aren’t cancer but do have the potential to become cancer if they aren’t treated - very rarely the borderline tumour cells can change into cancer cells. These tumours are usually treated and cured with surgery with a small risk of the tumour coming back.

Taking Hormone Replacement Therapy (HRT)

Taking hormonal replacement therapy (HRT) after the menopause can slightly increase your risk of developing ovarian cancer. Around 4% of ovarian cancer cases in the UK may be linked to taking HRT. Remember the risk associated with taking HRT is small and it can be very helpful if you are experiencing symptoms while going through the menopause. You should talk to your GP about the benefits and risks of HRT before making a decision about whether to take it.

Being overweight or obese

Being overweight or carrying excess body fat is linked to an increased risk of ovarian cancer, so try and stay at a healthy weight if you can. If you are struggling to lose weight try speaking to your GP.

Smoking

Smoking can increase your risk of being diagnosed with a less common type of ovarian cancer called mucinous cancer. The longer you have been smoking, the greater the risk. Try to cut down or quit smoking. If you’re struggling to quit try speaking to your GP or pharmacist as there is lots of support available.

Fertility drugs

There have been some studies which have supported the idea that women who have been treated with fertility drugs may have a slightly higher risk of ovarian cancer when compared to women who have not been treated, but the number of cancers is very low. There is ongoing research in this area and currently there is limited information about the dose or type of fertility drugs that are used. If you have been treated with fertility drugs, or are considering fertility treatment and are concerned or have any questions, please speak to your doctor.

A family history of ovarian cancer, also known as hereditary risk

Ovarian cancer can also run in families, which is known as a hereditary or inherited risk. If your mother, your sister or your daughter has had (or currently has) ovarian cancer then your own risk is increased. This risk may increase further if they were diagnosed when they were younger and if you had multiple relatives affected.

Inherited genetic conditions

Our genes contain our genetic information, which is passed on from our parents. Some cancers, like ovarian cancer, can be caused by an inherited mutation (change) in certain genes. Between 5 and 15% of ovarian cancers are believed to be caused by a change contained within one of genes which have been passed on in the family. Mutations in the BRCA1 and BRCA2 genes are responsible for the majority of inherited ovarian cancers. If you have a mutation in one of these genes, you have a higher risk of being diagnosed with ovarian cancer than the general population; if your mutation is in the BRCA1 gene, your risk of developing ovarian cancer is up to 65% higher, and if your mutation is with the BRCA2 gene, it is up to 35% higher. Understanding your personal inherited risk.

If you are concerned about hereditary risk of developing ovarian cancer, you might benefit from visiting a consultant geneticist to better understand your personal risk and the options available to you. Find out more about hereditary cancer and genetic testing.

Other conditions

Some studies have shown that endometriosis or diabetes can increase your risk of ovarian cancer. If you are diabetic and use insulin that can increase your risk further.

There's evidence to suggest that women with endometriosis have an increased risk of developing ovarian cancer, but these studies also show that having endometriosis only slight increases the risk of ovarian cancer. So having endometriosis isn’t necessarily a huge cause for concern, but is worth being aware of.

Protective factors that can reduce your risk of ovarian cancer

There are some factors which may reduce your risk of ovarian cancer. Whilst they may lower your risk it's important to remember that they won’t completely prevent you from being diagnosed with ovarian cancer so it’s important to be aware of the symptoms.

Some protective factors include:

  • Taking the combined contraceptive pill. When taken for ten years or more, the combined contraceptive pill is known to reduce your risk of ovarian cancer by almost 50%. The longer you take the pill, the more your risk is reduced, and this reduction can last for over ten years after you stop taking the combined contraceptive pill. Despite these positive benefits, it’s important to know that there are potential health risks associated with the taking the combined contraceptive pill and these should be discussed with your GP.
  • Having children and breastfeeding. The fewer times you ovulate (produce eggs) in your lifetime, the lower your risk of ovarian cancer. Pregnancy and breastfeeding can reduce your chance of developing ovarian cancer because during pregnancy the ovaries don't ovulate, and if you breastfeed after you give birth this then delays the start of ovulation. The more children you have, particularly if you breastfeed, the lower your risk - as having more ovulatory cycles raises the risk of ovarian cancer, so fewer cycles reduces the risk.
  • Having a hysterectomy or having your tubes tied. If you have decided that you don’t want to have any more children you may have had your fallopian tubes tied, which is known as sterilisation. This procedure is known reduce ovarian cancer risk. It was also previously accepted that people who have had a hysterectomy (an operation to remove the womb) had a lower risk of ovarian cancer. It’s now understood that the risk reduction will depend on factors such as how old you were when you had the surgery, with the effect more apparent in younger women.

If you would like to know more about ovarian cancer diagnosis and treatment and other gynaecological cancers visit our gynaecological cancer hub here for more information.