Cancer that forms in tissues of the breast, usually the ducts, tubes that carry milk to the nipple and lobules, the glands that produce milk, is defined as breast cancer. This type of cancer can occur in both men and women, although male breast cancer is rare. In the U.S., breast cancer affects approximately one in eight women.
Worldwide, breast cancer is among the most frequently diagnosed life-threatening cancer in women and the leading cause of cancer deaths among women.
Epidemiology of Breast Cancer
Almost 50 percent of women will consult their doctor regarding a breast complaint such as a lump. Approximately 25 percent of women will undergo a biopsy on the breast and one in eight will develop breast cancer. The current life-time risk for this type of cancer is 12.7 percent for women. Approximately a third of women diagnosed with breast cancer will die of the disease each year.
Two percent of breast cancer cases occur in women under the age of 30 years and 70 percent or women diagnosed are over the age of 50 years. The genetic factors for breast cancer, genes called BRCA1 and BRCA2 account for only 10 percent of breast cancers. The male to female ratio for this cancer is 1:100.
General and Major Risk Factors for Breast Cancer
General risk factors increase the likelihood of developing breast cancer by one to two fold. These include factors such as early age of onset of menstruation, obesity, a sedentary lifestyle, alcohol consumption, having a late first pregnancy (over the age of 35 years), nulliparity or having more than one pregnancy, a history of ovarian or endometrial cancer and increasing age.
Major risk factors for breast cancer increase the likelihood of this disease by more than four times. These factors include having a first degree relative with breast cancer; almost 30 percent of women diagnosed with breast cancer have at least one relative with a history of this disease; however, only five to 10 percent of women have an identifiable hereditary predisposition. Advanced age, positive genetic factors called BRCA1/BRCA2 mutations and a previous breast biopsy showing atypical hyperplasia or cell growth are also significant risk factors for breast cancer.
Breast Cancer Screening Guidelines
The American Cancer Society advises that women should be screened for breast cancer with the following guidelines.
- Women aged 20 to 39 years: Perform a monthly self breast exam and have a clinical exam by a healthcare professional every three years.
- Women aged 40 and higher: Perform a monthly self-exam on the breasts and have a yearly clinical breast exam. Also have a mammogram every one to two years as advised by your doctor.
Related Articles:
Stages and Survival Rates of Breast Cancer
References:
American Cancer Society: Risk Factors for Breast Cancer (accessed January 20, 2011).
National Cancer Institute: Breast Cancer
Noreen Kassem - Noreen Kassem is a hospital doctor based in London, UK. She has extensive experience in clinical research and an undergraduate honors ...
