Younger women generally do not consider themselves to be at risk for breast cancer, and in fact, just under 7% of all breast cancer cases occur in women under 40 years old. However, breast cancer can strike at any age, and women of every age should be aware of their personal risk factors for breast cancer.
There are several factors that put a woman at high risk for developing breast cancer, including:
A personal history of breast cancer or some noncancerous breast diseases.
A family history of breast cancer, particularly in a mother, daughter, or sister.
History of radiation therapy to the chest before age 40.
Evidence of a specific genetic defect (BRCA1/BRCA2 mutation); women who carry defects on either of these genes are at greater risk for developing breast cancer.
A Gail Index score of at least 1.7% for the development of breast cancer within 5 years, or 20% lifetime risk (to age 90). (The Gail Index uses risk factors such as age, family history of breast cancer, age of first menstrual period and first pregnancy, and number of breast biopsies, to calculate a woman's risk of developing breast cancer within the next five years.)
Other risk factors include heavy alcohol use, high intake of red meat, dense breasts, obesity, and race.
Some studies have suggested that recent use (during the past 10 years) of oral contraceptives (birth control pills) results in a very slight increased risk for developing breast cancer over those who have never taken them. Other studies, however, show no such effect. Researchers continue to study the conflicting results in these trials to determine if birth control pills, synthetic hormones (estrogen and progesterone/progestin), play a role in breast cancer.
However, hormone replacement therapy with estrogens and progestins have been linked to a higher risk of breast cancer development.
What Is Different About Breast Cancer in Younger Women?
Diagnosing breast cancer in younger women (under 40 years old) is more difficult, because their breast tissue is generally denser than the breast tissue in older women. By the time a lump in a younger woman's breast can be felt, the cancer often is advanced.
In addition, breast cancer in younger women may be aggressive and less likely to respond to treatment. Women who are diagnosed with breast cancer at a younger age are more likely to have a mutated (altered) BRCA1 or BRCA2 gene.
Delays in diagnosing breast cancer also are a problem. Many younger women who have breast cancer ignore the warning signs -- such as a breast lump or unusual nipple discharge -- because they believe they are too young to get breast cancer.
Many women assume they are too young to get breast cancer and tend to assume a lump is a harmless cyst or other growth. Some health care providers also dismiss breast lumps in young women as cysts and adopt a "wait and see" approach.