Understand your risk of cancer

20 Aug 2021

Understanding your cancer risk factors and your individual risk profile can help you learn lifesaving information. Here at Pink Hope, we encourage all women to know their breast and ovarian cancer risks.

Knowing about your risk of cancer means finding out how likely you are to develop it, whether there are ways to detect it early and how you might reduce the risk

  • What is cancer?

The human body is made up of billions of cells, which frequently renew themselves. Cell renewal is normal - new cells grow to replace old ones that get destroyed. Cell renewal happens for a variety of reasons. Cancer begins when cells in the body stop renewing at the normal rate and grow uncontrolled.

We all have genes to help our cells keep the rate of cell renewal and growth at the normal rate. However, sometimes these genes can stop working properly and sometimes it disrupts the process that keeps cell growth in check. Once cells grow out of control, this is the first step in the process of a cancer developing.

What causes these genes to stop working is largely unknown. Sometimes, there are risk factors in common including smoking, alcohol consumption, dietary influences, exposure to radiation or infectious agents, and inherited ‘faulty’ genes, or mutations. Cancer is not a single disease with a single type of treatment. There are over 200 different kinds of cancer, each with its own name and treatment.

  • How common are breast and ovarian cancers?

The first thing to know is that most women don’t develop breast or ovarian cancer. There are three major risk categories for breast and ovarian cancer: low (also known as average risk or general population risk), moderate and high risk. Each level of risk has different recommendations for screening and/or risk reducing strategies.

Several factors such as personal health history, family health history and lifestyle factors can affect your breast and ovarian cancer risk. You can discuss your cancer risk with your GP (local doctor). If you have a family history of breast or ovarian cancer, our Peter MacMillan Know Your Risk tool may be helpful in guiding you further about what the family history means for your risk.

Here’s a bit of information about these three levels of risk so you can see where you sit.

The Low-Risk Category – Most women in the population fall into this category. This category is also referred to as ‘average risk’ or ’general population risk’. Most women in this category will not develop breast or ovarian cancer in their lifetime. The risk of breast cancer, for women in this category, is about 12.5% over a lifetime. Another way to put this is about 1 in 8 women will develop breast cancer. The risk of ovarian cancer is about 1.2% over a lifetime. This means that fewer than 1 in 80 women will develop ovarian cancer. The majority of breast and ovarian cancers occur in women after age 50.

The Moderate-Risk Category Some women in this category will develop breast or ovarian cancer but most will not. The lifetime risk of breast cancer for women in this category is moderate. This means as a group, risk of breast cancer up to age 75 is between 1 in 8 and 1 in 4. This risk is 1.5 to 3 times the population average. It is more than the population risk of 12.5% (1 in 8) but less than 30% (less than 1 in 3).

Most women in this group will have an ovarian cancer risk up to the age of 75 of between 1 in 100 and 1 in 30. This risk is no more than 3 times than the population average.  If a woman has one immediate relative (sister, mother or daughter) who has ovarian cancer, then her ovarian risk may be slightly increased to about 4% (4 in 100).

The High-Risk Category Less than 1% of the female population have a high risk of breast or ovarian cancer. The risk of breast cancer up to age 75 is between 1 in 4 and 1 in 2. Risk may be more than 3 times the population average. Individual risk may be higher or lower if genetic test results are known. The risk of ovarian cancer up to age 75 is between 1 in 30 and 1 in 2. This risk is more than 3 times the population average. Again, individual risk may be higher or lower if genetic test results are known. 

Some women have a high risk of both cancers, others only of breast or of ovarian cancer. This varies depending on the pattern of family history and/or what they have found through genetic testing.