A number of the general features of breast cancer statistics are
provided in:
Regional variations in breast cancer incidence across Canada are
illustrated using maps of incidence
rates and ratios.
As much as possible, these two maps should be examined together.
Risk Factors, Prevention and Trends
The cause of breast cancer is unknown and it cannot be prevented.
Other than being a woman, the most significant risk factor associated
with breast cancer is aging. What a bitter irony! As life expectancy
rises so too does the chance of getting breast cancer.
Health Canada lists the following additional risk factors:
- family history of breast cancer
- a history of cancer in one breast
- history of certain types of benign breast disease and high levels
of radiation exposure to the chest
- obesity in postmenopausal women
- various reproductive risk factors, such as:
- never having had children being 30 or more years of age at first
full-term pregnancy
- having an early onset of menstruation and a late onset of menopause
- various demographic factors, such as: living in an urban area
- belonging to a higher socioeconomic class
- being born in North America or Northern Europe
Early detection is the best way of saving lives. "At present,
the only proven strategy to reduce breast cancer deaths is early
detection through mammography in women aged 50 to 69. There is clear
evidence from population-based trials that mammographic screening
can reduce mortality from breast cancer by approximately 30% in
women aged 50 to 69" (Health Canada).
Currently, mammograms are recommended every two years for women
50 to 69 years of age. Unfortunately, while from 1990 to 1997 there
has been a "dramatic increase of 28 percentage points in the
proportion of women age 50 and older who have ever had a mammogram",
the increase in the proportions of women who have had a mammogram
within the past two years has been modest (Federal, Provincial and
Territorial Advisory Committee on Population Health (1999); Snider
et al. (1966)).
Breast cancer has risen steadily during the past 30 years, particularly
in the last decade (Figure 1). The latter increase is partially
due to more effective detection methods. Early detection and improved
treatment techniques have resulted in significantly fewer deaths.
[D] Click for larger version, 8 KB Figure 1. Breast and Lung Cancer Incidence and Mortality Rates, 1970 to 1999
The declining mortality rate for breast cancer stands in stark
contrast to the increasing mortality rate for lung cancer for women.
The incidence and mortality rates for both of these cancers have
been placed on this same graph to illustrate the differences that
Canadian women are experiencing with these two diseases.
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