What is my risk of breast cancer?

What is my risk of breast cancer? 

Everyone has some level of risk of breast cancer, but the good news is, you can take steps to reduce it. Understanding your personal risk factors is the first step toward prevention. 

This guide breaks down the science in a clear, easy-to-understand way, explaining what influences your risk. 

The factors you can't change. 

Your risk of developing breast cancer is shaped by a combination of factors: 

• Age: as you get older, your risk increases due to the accumulation of genetic mutations over time. 
• Gender: being born female means higher lifetime exposure to oestrogens, which can stimulate cell growth in breast tissue. 
• Breast density: high breast density is a risk factor. It’s partly genetic and can change over your lifetime. 
• Ethnicity: black women from Caribbean and African backgrounds are up to two times more likely to receive a late-stage diagnosis for some cancers than white British women in England. 
• Breast cancer history: a history of benign (non-cancerous) breast disease or previous breast cancer increases your risk. 
• Reproductive history: starting your periods early (before 12) or reaching menopause late (after 55) means longer exposure to oestrogens. 
• Physical traits: being tall, having a higher birth weight (above 4kg) or large early body size may increase risk, possibly due to higher levels of growth hormones. 
• Higher levels of naturally circulating sex hormones (such as oestrogen) increase breast cancer risk. 

Genetic factors: 

• Some people inherit gene mutations, like BRCA1 or BRCA2; they are uncommon, but they do increase risk.  
• If you have a family history of breast cancer (mother, sibling or daughter, especially at a young age), this approximately doubles your risk. 
• Genetic variation in multiple genes and other regions of DNA is also associated with an increased breast cancer risk.

The factors you can influence.

• Any amount of alcohol increases risk. It's been shown to raise estrogen levels and can damage DNA. 
• Regular physical activity helps to lower hormone levels, like estrogen, that are linked to cancer growth. Staying active is a simple but effective way to reduce your risk. 
• A diet rich in fruits, vegetables, and fibre may help reduce your risk. 
• Being overweight after menopause, mainly due to higher oestrogen levels,  is also linked to increased risk. 
• Having children at a younger age (before 30) and having more children younger can reduce your risk too. 
• Breastfeeding can reduce your risk; the longer you do it, the larger the risk reduction. 
• Smoking, especially if you start young or continue long-term, increases your risk. 
• The combined pill slightly increases risk, however the risk is no longer evident after use has stopped for 10 years.  
• Combined Hormone Replacement Therapy (HRT) can slightly increase your risk, especially with long-term use (over 5 years).
• Breast cancer is more common in high-income countries. In the UK, women in lower-income areas often face later diagnosis; this could be due to lower screening uptake and awareness, which affects outcomes. 

Other risk factors.

Environment and chemical exposures: 

• Pollution: breathing in polluted air, which contains harmful chemicals, may increase your risk. 
• Everyday products: many common products may contain Endocrine Disrupting Chemicals (EDCs) that can mimic hormones and may increase breast cancer risk. 

Medical and radiation: 

• Radiation: high-energy radiation, like from certain medical treatments or nuclear fallout, especially during puberty, can damage your DNA and raise your risk. 
• DES: if you or your mother were exposed to DES, a drug once used to prevent miscarriage, you may have a higher risk.