Worldwide statistics on breast cancer: Diagnosis and risk factors
Breast cancer is the only cancer that is considered universal among women worldwide.
In this article, we take a look at various breast cancer statistics for the global population and for the United States.
Contents of this article:
Worldwide breast cancer rates and deaths
The majority of new breast cancer diagnoses and deaths occur in developing countries as opposed to Western countries. The higher number of cases in developing countries is partly due to their larger portion of the world’s population.
However, rates have been steadily increasing in these non-developed nations as well, in recent decades. Breast cancer is now the leading cause of cancer-related deaths in women in the world’s developing regions.
The breast cancer incidence, or the number of cases per 100,000 women, is still lower in developing countries overall than in the West, but death rates from the disease are higher. This may be attributed to later diagnosis and poor access to treatment.
By contrast, the rate of breast cancer per 100,000 women is higher in the U.S., Canada, and Europe than it is in developing countries. Conversely, death rates are markedly lower.
In westernized countries, more breast cancer cases are detected early when a cure is more likely and more women are able to get treatment.
Furthermore, in developed countries breast cancer is second to lung cancer for cancer-related deaths in women.
Prevalence of breast cancer
- Percentage of world population: 59
- Percentage of new breast cancer cases: 39
- Percentage of breast cancer deaths: 44
- Percentage of world population: 15
- Percentage of new breast cancer cases: 8
- Percentage of breast cancer deaths: 12
U.S. and Canada
- Percentage of world population: 5
- Percentage of new breast cancer cases: 15
- Percentage of breast cancer deaths: 9
(Data from Global Cancer Facts and Figures, 3rd Edition, page 37)
Incidence rates per 100,000 women
Countries with highest incidence:
- The Netherlands: 95.3
- France: 94.6
- U.S: (white people only – other races have lower incidence): 90.6
Countries with lowest incidence:
- Thailand: 25.6
- Algeria: 29.8
- India: 30.9
(Data from Global Cancer Facts and Figures, 3rd Edition, page 42)
Diet and obesity
Obesity is a risk factor for breast cancer because body fat may increase levels of estrogen in the body, particularly after menopause. The World Health Organization state that obesity across the world has more than doubled since 1980.
Higher body fat may be associated with higher breast cancer risk, according to the American Cancer Society. Hence, increasing rates of obesity could account partly for the global increase in breast cancer rates.
Specific details of diet have not been proven to cause breast cancer directly. But they may play a role in raising the risk. A recent study by the MD Anderson Cancer Center found that a diet high in sugar might lead to an increase in tumor growth and spread.
In addition, Cancer Research UK state that a diet high in saturated fats may contribute to a higher breast cancer risk in some people.
Asian and African nations, where breast cancer rates are lower overall, tend to eat less of the sugar, saturated fat, and processed foods that are common in the typical western diet.
Racial differences within the U.S.
According to the Centers for Disease Control and Prevention (CDC), 230,815 women and 2,109 men in the U.S. were diagnosed with breast cancer in 2013. In the same year, some 40,860 women and 464 men in the U.S. died from breast cancer.
With the exception of skin cancer, breast cancer in the U.S. is the most common cancer in women across all races. However, the rates per 100,000 women differ greatly among certain races and ethnicities:
Rates per 100,000 women in U.S.:
- all races: 123.7
- white: 124.4
- black: 122.9
- Hispanic: 92.5
- Asian and Pacific Islander: 91.1
- American Indian and Alaska Native: 72.3
The differences among different races could be due in part to reproductive patterns. For instance, white women are more likely to put off childbirth longer and to have fewer children overall.
The average body weight of certain ethnicities and the use of menopause hormone therapy may also play a role in these different incident rates.
Breast cancer risk factors
One of the reasons that breast cancer is thought to have increased worldwide is the changes in hormones related to:
- the number of and age when pregnancies occurs
- the number of children a woman has
- the use of supplemental hormones
A woman’s breast cancer risk is higher if she has her first full-term pregnancy after age 30, or if she never has a full-term pregnancy. This may be due to the breasts being exposed to the higher total levels of estrogen and progesterone that occur during menstrual cycles.
Pregnancy and breast-feeding reduce the number of menstrual cycles and total exposure to these hormones during a woman’s lifetime.
Similarly, if a woman begins menstruating at a younger age, or completes menopause at a later age, she has more menstrual periods. This means that she will have a higher lifetime exposure to these hormones and a higher risk of breast cancer.
Taking certain supplemental hormones may also increase the risk of breast cancer. This includes taking estrogen and progestin during menopause, but only if taken for 5 years or more.
Certain forms of birth control pills that contain estrogen and progestin might also increase breast cancer risk. The risk is higher if the woman has a family history of breast cancer, has a breast cancer gene, or has had abnormal breast cells in the past.
These hormonal factors have affected the rates of breast cancer worldwide. Western countries have had access to contraception and lower fertility rates for decades. Now developing countries have had widespread access to these treatments more recently as well.
Fertility rates in many developing countries have declined in recent decades. This is because contraception use has increased and people are choosing to have fewer children or begin families later in life.
Certain lifestyle changes may lower a woman’s risk of getting breast cancer regardless of where she lives. These include:
- work toward or maintain a healthy weight
- avoid or limit menopause hormone therapy
- limit alcohol consumption to one drink per day or less
- get regular exercise and avoid being sedentary
Many factors that affect breast cancer risk cannot be controlled. They include:
- being age 55 or older
- having the BRCA1 or BRCA2 genes or certain other gene mutations
- having dense breast tissue
- going through menopause later in life or starting menstruation at a younger age
Still, many women who follow a healthful lifestyle and have no known risk factors get breast cancer.
Because many aspects of breast cancer remain a mystery, medical experts recommend screening and watching for breast changes so breast cancer can be caught early.