Breast cancer: introduction
Breast cancer is the most common cancer in women in Scotland with over 3,900 cases now being diagnosed each year. The prognosis is generally favourable with around 80% of women surviving at least 5 years after their breast cancer diagnosis. This is likely to be due to a number of factors, including the impact of the Scottish Breast Screening Programme and advances in treatment.
Many of the known risk factors for breast cancer relate to a woman's reproductive history, e.g. early menarche, late first pregnancy, low parity, not breastfeeding and late menopause. Risk of breast cancer is largely determined by lifetime exposure to oestrogens and risk increases substantially with age.
Chart 1 shows the estimated cumulative incidence of breast cancer in developed countries if women had family sizes and breastfeeding patterns typical for developing countries. It is estimated that the incidence of breast cancer could be reduced from around 6.3 to 2.7 per 100 women if women in developed countries had larger family sizes and longer duration of breastfeeding.
Breast cancer incidence is expected to continue rising in Scotland over the next 20 years (see the Cancer Scenarios planning report). In support of this, Chart 2 shows an upward trend over the past 25 years in the mean age of women in Scotland at the birth of their first child.
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