Yes, you are susceptible…

But your risk of getting breast cancer is dependent on many factors.  Some are related to your genes. Others could depend on what happened to you in the womb and growing up, your environment, and how you live your life now.  Whatever your susceptibility, you can help yourself by adopting strategies, like maintaining a healthy diet or changing your lifestyle, to give yourself the greatest to reduce your risk.

Although uncommon, men can also develop breast cancer. Several, but not all, risk factors are common to both men and women. Please see here for a link to our science review which discusses breast cancer in men.

Some of the factors which influence your susceptibility

Physical make-up

• Age is the most significant risk factor for female and male breast cancer. As you age, mutations accumulate in your cells, including those that increase your risk of cancers, including breast cancer.
• Being born female often means having more breast tissue that is susceptible to breast cancer and a higher lifetime exposure to oestrogens, which can stimulate cell division and growth and promote the growth of certain types of breast tumours. Risk of breast cancer is still thought to be higher in trans men who undergo hormone treatment – see our Transgender resource for more information.
• High breast density is one of the strongest risk factors for breast cancer. Breast density (also known as mammographic density) can only be identified by a mammogram (breast X-ray) and is partly genetic and partly influenced by environment, it can also change over a lifetime.
• Ethnicity can contribute to your breast cancer risk. In the UK, breast cancer is more common in white women than in South Asian, Chinese and Black women. Individuals with an Ashkenazi background also have a higher risk of inheriting a BRCA gene mutation which increases breast cancer risk (see ‘Genes and family background’ below for more details on BRCA).
• A history of certain types of benign breast disease or a previous breast cancer diagnosis means you have an increased risk of breast cancer. Breast cancers commonly occur in women with atypical hyperplasia and proliferative disease without atypia (see glossary). Two types of non-invasive breast cancer, lobular carcinoma in situ and ductal carcinoma in situ, are also associated with an increased risk of breast cancer.
• Starting your periods early (before 12) or reaching menopause late (after 55) are factors that contribute to a higher risk of breast cancer. This is thought to be related to the longer time period that high concentrations of oestrogens are circulating in your body.
• Being tall can make you more susceptible, possibly due to the higher levels of growth hormone and certain growth factors in your body during early development.
• A birth weight above 4kg and large early body size before the age of 18 means you are at an increased lifetime risk of developing breast cancer. 
• Higher levels of naturally circulating sex hormones (oestrogen, progesterone and testosterone) increases breast cancer risk. Post-menopausal women with higher levels of naturally circulating oestrogen have around twice the risk of breast cancer compared to those with lower levels.

Environment

• Environmental carcinogens present in polluted air (for example dioxins and polychlorinated hydrocarbons), or as a result of working in hazardous occupations, can increase breast cancer risk.
• Endocrine Disrupting Chemicals (EDCs) which are found in many everyday products can mimic, block, or interfere with hormones in the body and may influence the development of breast cancer.
• Exposure to diethylstilboestrol (DES) during pregnancy or in utero. DES is a synthetic oestrogen and EDC, which was used as an anti-miscarriage drug until the 1970s. Women who took DES, along with their daughters, have a higher risk of breast cancer.
• Air pollution contains carcinogens, EDCs and particulate matter (fine particles 10 micrometres or less in size) which may contribute to increased breast cancer risk.
• Radiation exposure as a result of radiotherapy for medical treatment, or from other high-energy sources (for example nuclear fallout, multiple chest X-rays), particularly during puberty, can damage your DNA which increases your risk of mutations and chances of developing breast cancer.
• Where you live affects your breast cancer risk. The highest rates of breast cancer occur in North and Western Europe, Australia, New Zealand, Canada and the US. The lowest rates are found in South Central Asia and Middle/Eastern Africa. In the UK and other countries, living in urban areas, as opposed to rural areas, is associated with an increased risk of breast cancer.

Lifestyle 

• Having children after the age of 30 or having no children can increase your risk of breast cancer. Having more children at a younger age reduces your risk.
• Breastfeeding reduces your risk and the longer you breastfeed the more your risk is decreased.
• Being overweight and adult weight gain are well-recognised risk factors for breast cancer in post-menopausal women, mainly due to increased levels of circulating oestrogens.
• Diet may also influence your breast cancer risk. Higher consumption of fruits, vegetables and other fibre-rich foods has been shown to reduce breast cancer risk. Conversely, a high intake of red/processed meat may increase risk.
• Lack of physical activity is a risk factor because physical activity helps lower levels of certain growth factors and hormones, including oestrogen – higher levels of these are associated with cancer development and progression.
• Drinking alcohol increases your risk; this is thought to be because alcohol can raise the concentration of circulating oestrogens, also, alcohol is broken down in breast tissue to produce by-products which may damage DNA.
• Smoking especially if you begin at an early age or have smoked for many years, increases your risk.
• Use of the combined contraceptive pill and implants (synthetic oestrogen and progesterone) can increase breast cancer risk slightly Risk increases with a longer duration of use and is no longer apparent 10 years after use has ceased. More research is needed to confirm whether progesterone-only contraceptive pills are associated with an increased risk of breast cancer.
• Use of combined Hormone Replacement Therapy (synthetic oestrogen and progesterone) carries an increased risk when used over five years. This risk decreases following cessation of use, but some risk remains if used over 10 years. HRT containing oestrogen only is associated with little to no risk.
• Socioeconomic status (SES) influences breast cancer risk. Breast cancer incidence rates are elevated in high-income countries compared to low/middle-income countries. In the UK, breast cancer incidence is reduced in lower SES areas compared to higher areas. This is likely due to lower screening uptake. However, women from these areas may also be less aware of breast cancer symptoms and are more likely to be diagnosed at a later stage which can influence treatment options.

Genes and family background

• Family History of breast cancer is relevant but as breast cancer is common, having a relative with the disease doesn’t necessarily indicate you have a genetic predisposition. Having a first-degree relative (mother, sibling or daughter) who has developed breast cancer (especially at a young age) approximately doubles your risk.
• Inherited single gene mutations such as BRCA1 and BRCA2 are uncommon but they do increase risk. Between 5-10% of breast cancers are thought to be caused by an inherited faulty gene.  Recent studies suggest the risk of getting breast cancer by the time you reach 80 if you carry a faulty BRCA1 or BRCA2 gene is around 70%. See the NHS website for comprehensive advice about genetic testing.
• Genetic variation in multiple genes and other regions of DNA is also associated with an increased breast cancer risk. Genetic variation (including single-gene mutations) is thought to account for around a fifth of all breast cancers.

Glossary

Atypical hyperplasia: a non-cancerous condition where the cells in breast tissue increase in number and develop an unusual appearance when viewed under a microscope. Women with this condition have an increased risk of developing breast cancer.

BRCA1/2: Stands for BReast CAncer genes 1 and 2. These are genes that everybody has which help prevent cells growing out of control. A fault in these genes can increase the risk of developing breast cancer due to uncontrolled cell growth.

Breast Density: Denotes the relative amounts of different tissue (fatty vs glandular) in the breast and is determined by a mammogram. High breast density equates to having more glandular tissue compared to fatty tissue and is a risk factor for breast cancer.

Carcinogen: a chemical, or other substance that promotes cancer development.

EDC: Endocrine Disrupting Chemical. These are chemicals that may have effects on the Endocrine System which manages hormones in the body.

Genetic variation: The difference in the sequences of DNA between individuals or between populations of the same species.

Hormones: Signalling molecules that act as messengers in the body. They travel through the bloodstream and transport information from one organ or tissue to another to help control their function.

Mutation: A change or fault in the DNA sequence of a gene that in some cases can increase the risk of certain diseases. Mutations can be inherited or acquired during a person’s lifetime due to certain factors.

Proliferative disease without atypia: A condition where breast cells grow significantly faster than average but demonstrate a normal appearance. Women with this condition have a slightly increased risk of breast cancer.

Last Review: November 2024

Next Review: November 2025