Division Of Public Health Systems

Maine Center for Disease Control & Prevention

A Division of the Maine Department of Health and Human Services

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Maine Cancer Registry - Female Breast Cancer: Risk Factors, Prevention & Early Detection

Breast Cancer in the U.S.

Breast cancer rates in the United States are among the highest in the world. Breast cancer is the most common cancer among women in the United States, accounting for 32% of all cancer in women. It is the second leading cause of cancer-related deaths (after lung cancer) among U.S. women. According to the 2006 American Cancer Society, Cancer Facts & Figures, an estimated 212,920 women in the U.S. will be diagnosed with breast cancer and 40,970 people will die from this disease annually. The incidence of invasive breast cancer in the United States increased 34 percent from 1975 to 1999 and has recently started to decrease. The mortality rate has declined since 1989. Although early detection (using mammograms) accounts for some of this increase in incidence, other factors play a role. From 1996-2002, 90.1% of White females and 77.3% of African American females survived for at least five years after being diagnosed with breast cancer.

Risk Factors for Breast Cancer

  • One of the strongest risk factors is older age.
  • Some genetic factors are believed to play a role in a small number of breast cancers, such as having a close female relative (mother, sister, daughter) with breast cancer or inheritance of the breast cancer gene BRCA1 or BRCA2.
  • Other factors related to a woman's medical history may increase risk, including:
    • First full-term pregnancy after age 30, or never having borne a child.
    • Being overweight (mainly after menopause).
    • A history of breast, ovarian, or endometrial cancer.
    • A typical hyperplasia or a high degree of dense breast tissue.
    • Long term use of high doses of estrogen (such as oral contraceptives or hormone replacement therapy).
  • Some environmental exposures may contribute to breast cancer risk, such as high doses of radiation in infancy or from puberty through the childbearing years or more than two drinks of alcohol a day.

Prevention of Breast Cancer

Most women with breast cancer do not have any known risk factors besides older age. However, some studies suggest that there are fewer cases of breast cancer among groups of women who do the following:

  • Maintain a healthy weight
  • Avoid prolonged use of estrogen
  • Do not drink excess amounts of alcohol

Early Detection of Breast Cancer

Why is early detection important?

  • Cases detected early (local disease) have about a 98% chance of living for at least five more years.
  • Cases detected at the distant stage (when disease has spread to another part of the body) have only a 26% chance of living for five more years.

How to Improve your Chances of Detecting Breast Cancer Early

  • Have a health care provider examine your breasts every year.
  • Learn from your provider how to examine your own breasts and do it every month.
  • Get your first screening mammogram when you turn 40 and earlier if your provider advises because of other risks factors, such as:
    • a close female relative with breast cancer
    • a biopsy with "atypical hyperplasia"
    • carrying the genes BRCA1 or BRCA2
  • Get a screening mammogram every 1-2 years between 40 and 49 years of age and every year after age 50.

For information on female breast cancer statistics in Maine, please see MCR's Annual Reports.