Risk factors for breast cancer

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Breast cancer is a disease in which malignant (cancer) cells form in any of the tissues of the breast. This includes cell which originate from the  lobes, ducts, connective tissue and fat. Many are now picked up by screening. Otherwise possible symptoms include a lump or swelling in the breast or armpit, dimpling of the skin, bloodstained discharge from the nipple, change in size, shape or skin colour of the breast (find out more)

Breast cancer is the most common cancer in the UK. Nearly 44,000 women are diagnosed every year in the UK. Overall, one woman in nine will get breast cancer at some point in her life. The lifetime risk of breast cancer depends on factors within three main categories: Lifestyle | genetic risk | other disease

National Cancer Institute has developed a risk of breast cancer calculator >>>>  Based on a series of published scientific trials the American Society of Clinical Oncology have issued guidelines that ant woman with a 5-year projected absolute risk of BC ≥ 1.66% (based on the National Cancer Institute BC Risk Assessment Tool or an equivalent measure) or women diagnosed with lobular carcinoma in situ should be offered drugs which could reduce their risk:

• ≥ 35 years, tamoxifen (20 mg per day for 5 years)
• Postmenopausal women, raloxifene (60 mg per day for 5 years) or exemestane (25 mg per day for 5 years) 

Lifestyle factors which increase the risk of breast cancer:

Certain

• Being overweight >>
• Excessive drinking of alcohol >>
• Unhealthy diet (high in fat) >>
• Smoking >>
• Lack of physical activity >>
• Diets deficient in polyphenols (fruit, herbs, vegetables, legumes, pulses, soy, spices) >>
• Long-term HRT (hormone replacement therapy or oral contraceptives)
• Being older, female, or white
• Early start of menstrual period (before age 12), or late menopause (after age 55)
• Having no children or having first child after age 30, not breastfeeding

Less certain: 

• Use of regular parabens and Aluminum deodorants >>
• Xenoestrogens in foods and pollution >>
• Vitamin D deficiency >>

For tips to improve your lifestyle factors and the risk of breast or other cancers see "Lifestyle and Cancer - the facts"

Medical conditions which increase breast cancer risk

• Previous exposure to radiation in the breast area  (previous treatment for Lymphoma)
• Frequent CT scan or xrays
• Diabetes
• Previous benign breast disease
• Previous DCIS or LCIS

Inherited (genetic) risks of breast cancer:

Less than half a percent of women carry the know genes for breast cancer particularly BCRA 1 or 2. Carrying these genes infers a significant lifestyle risk of breast cancer (>80%). Even in individuals who do not carry the gene the risks can be higher if they have a strong family history or any of the features listed below. Recent scientific trials have suggested there is a benefit for taking prophylactic medication to prevent breast cancer if the 5-year projected absolute risk of breast cancer is ≥ 1.66% (based on the National Cancer Institute BC Risk Assessment Tool or an equivalent measure) or women diagnosed with lobular carcinoma in situ. 

Factors which correlate with an increased genetic risk of breast cancer;

• Number of first degree relatives with breast cancer
• First degree relatives getting breast cancer at a young age
• Relatives with bilateral breast cancer
• Male relatives with breast cancer

Any women with these risk factors could discuss genetic testing with their GP