Prevention and Risk Factors

Risk Factors

  • Being a woman and getting older are the greatest risk factors – neither of which we can do much about! Breast cancer is relatively uncommon before the age of 30, but risk increases with age as a woman approaches and goes through menopause. Risk continues to rise with age following the menopause, but the rate of increase is less pronounced; 24% of women diagnosed are under 50, 42% aged 50 to 64, 34% over 65 (NCRI, 2009-2013). The chance of a woman in Ireland developing breast cancer by the age 79 is 1 in 9.
  • 5 to 10% of breast cancer is hereditary and caused by inherited mutations (changes) in genes. Having one or more close relatives (sister, mother, daughter) who have been diagnosed with breast or ovarian cancer also increases a woman's risk of getting the disease
    • particularly if more than one relative is affected
    • the affected relative(s) were diagnosed under 40
    • your father’s side of the family is as significant as your mother’s
    • women of Ashkenazi Jewish heritage have a much higher rate of these genes, as do Icelandic women
  • Many of the important risk factors for breast cancer relate to the female sex hormones (oestrogen and progesterone) and your lifetime exposure to these and other hormones:
    • early onset of periods
    • late age at first pregnancy
    • late menopause
    • few or no children

Being taller and a heavier weight at birth also seem to be significant risk factors.

But breastfeeding and having children early appear to reduce risk.

These relationships suggest that exposure to oestrogen plays a very significant role in breast cancer risk, and this is supported by the observations that current or recent use of oral contraceptives and hormone replacement therapy (HRT) also increase risk. 

Aspects of lifestyle that appear to affect the risk of developing breast cancer include:

  • Being overweight or obese (post-menopausal women)
  • Drinking alcohol
  • Physical inactivity
  • Smoking

Prevention

While many risk factors are not modifiable, there are ways in which risk can be decreased:

  • Maintain a healthy weight
  • Exercise daily
  • Eat a well-balanced diet
  • Avoid or limit alcohol intake

Even if you can’t prevent breast cancer you will improve your chances significantly if you are diagnosed early, so be sure to watch out for breast changes, report any to your doctor and attend screening if you are in the screening age group.

Sources

Breast cancer incidence, mortality, treatment and survival in Ireland: 1994-2009. National Cancer Registry, Cork, Ireland (2013) www.ncri.ie

Cancer in Ireland 2013: annual report of the National Cancer Registry. National Cancer Registry, Cork Ireland (2013) www.ncri.ie

Cancer in Ireland 1994-2013: Annual Report of the National Cancer Registry. National Cancer Registry, Cork, Ireland. (2015) www.ncri.ie

EUROPA DONNA - The European Breast Cancer Coalition websites     www.europadonna.org  www.breasthealthday.org

Breast Cancer Now (formerly Breakthrough Breast Cancer and Breast Cancer Campaign)  www.breastcancernow.org [This website has very good information listing established, possible and doubtful risk factors and has a downloadable booklet: Breast Cancer Risk: The facts.]

WCRF (World Cancer Research Fund) Cancer prevention and survival: survey of global evidence on diet, weight, physical activity and what increases or decreases your risk of cancer. July 2016 edition. Downloadable at www.aicr.org