Breast cancer is the most common cancer in women worldwide after skin cancer. It represents 16% of all cancers in women. This rate is twice that of colorectal cancer and cervical cancer and about three times that of lung cancer. Death rates are also 25% greater than that of lung cancer in women.
Incidence of breast cancer around the world
All around the world the incidence of this cancer shows varied rates. The rates are low in less-developed countries and greatest in the more-developed countries. Breast cancer is related to age with only 5% of all breast cancers occur in women under 40 years old.
In the twelve world regions, the annual age-standardized incidence rates per 100,000 women are as follows:
Eastern Asia – 18 per 100,000 women
South Central Asia - 22 per 100,000 women
Sub-Saharan Africa – 22 per 100,000 women
South-Eastern Asia – 26 per 100,000 women
North Africa - 28 per 100,000 women
Western Asia - 28 per 100,000 women
South and Central America - 42 per 100,000 women
Eastern Europe - 49 per 100,000 women
Southern Europe - 56 per 100,000 women
Northern Europe - 73 per 100,000 women
Oceania - 74 per 100,000 women
Western Europe - 78 per 100,000 women
North America - 90 per 100,000 women
In the United Kingdom
Breast cancer has been the most common cancer in the UK since 1997. It accounts for 31% of all new cases of cancer in females. In 2010, there were 49,961 new cases of breast cancer in the UK. There are 157 new breast cancer cases for every 100,000 females in the UK. The rates are lower in Northern Ireland than in England, Wales or Scotland.
Higher incidence rates are seen among older women, supporting a link with hormonal status. Between 2008 and 2010, an average of 45% of cases were diagnosed in women aged 65 years and over, and 80% were diagnosed in the 50s and over. Nearly half (48%) of female breast cancer cases are diagnosed in the 50-69 age group. Incidence is lower among women from low socioeconomic strata.
The lifetime risk of developing breast cancer in the UK is estimated to be 1 in 8 for women. Among all detected cases 41% in 2009 were detected as stage 1, 45% at stage II, 9% at stage III and 5% at stage IV.
In the United States
In the US, around 1 in 8 women carry a lifetime risk of invasive breast cancer. In 2011, an estimated 230,480 new cases of invasive breast cancer were expected to be diagnosed in women in the U.S., along with 57,650 new cases of non-invasive (in situ) breast cancer. In addition, around 39,520 women in the U.S. were expected to die in 2011 from breast cancer.
There was a steady decline in breast cancer incidence from 1999 to 2005. The decrease was seen only in women aged 50 and older. This could be due to reduced use of hormone replacement therapy (HRT) by women.
Those with a family history of breast cancer are at double the risk of developing the cancer. About 15% of women who get breast cancer have a family member diagnosed with it. About 5-10% of breast cancers can be linked to gene mutations (abnormal changes) inherited from one’s mother or father. The most common mutations are those of BRCA 1 and BRCA 2. Women with these mutations have up to an 80% risk of developing breast cancer during their lifetime.
For women in the U.S., breast cancer death rates are higher than those for any other cancer, besides lung cancer. However, death rates are on the decline due to advances in therapeutics against breast cancer.
White women are slightly more likely to develop breast cancer than African-American women. However, in women under 45, breast cancer is more common in African-American women than white women. Asian, Hispanic, and Native-American women have a lower risk of developing and dying from breast cancer.
Breast cancer is the most common cancer among Australian women after melanoma or skin cancers. Breast cancers accounted for 28.2 per cent of all new cancers in women in 2008. Breast cancer is the second leading cause of cancer-related death in Australian women, accounting for 15.5 per cent of all cancer deaths in women in 2007.
The average age at diagnosis is usually around 60 years. The risk of developing breast cancer increases with age. The number of new cases of breast cancer diagnosed in women has increased from 5,310 in 1982 to 13,567 in 2008 and by 2020, it is estimated that there will be 17,210 new cases of breast cancer diagnosed in women. Breast cancer is the most common cancer in Aboriginal and Torres Strait Islander women.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)