Breast Cancer: Breast Cancer in Young Women

Learn the facts and get information about breast cancer.

Families with Breast Cancer

Medical Author: Carolyn Janet Crandall, MD, FACP
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Ms. G. is a 40-year-old woman with two small children. Like most women, she is concerned about her chances of developing breast cancer. She asks her doctor about her risks. Although breast cancer is a worry for most women, Ms. G. is especially worried because of a family history of breast cancer. Her mother and sister had breast cancers that were diagnosed at young ages.

A woman with a family history of breast cancer has a lot of concerns. Among other things, she is thinking of her job, children, and husband, as well as how her medical insurance and health team will be able to serve her needs in the future should a crisis arise.

What are the facts about families that have multiple members with breast cancer?

Inherited breast cancer disorders account for a small minority of breast cancers overall. Genes are the "messages" in each cell of the body that determine the ultimate design of our bodies. Genes can be damaged by the environment. Additionally, people can be born with defects in the genes that remove the body's defenses against cancers. Only in about 10% of all breast cancer cases is there actually a genetic defect that can be tested. This means that 90% of breast cancers are due to other causes. In fact, most cases of breast cancer occur in women who do not have a family history of breast cancer. A complex interplay between environmental and genetic factors affect the development of breast cancer, and all the key factors have not yet been identified.

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Younger women generally do not consider themselves to be at risk for breast cancer. Only 5 percent of all breast cancer cases occur in women under 40 years old. However, breast cancer can strike at any age, and all women should be aware of their personal risk factors for breast cancer. (A risk factor is a condition or behavior that puts a person at risk for developing a disease.)

There are several factors that put a woman at high risk for developing breast cancer, including:

Risk factors include:

  • A personal history of breast cancer or non-cancerous breast disease
  • A family history of breast cancer, particularly in a mother, daughter or sister
  • History of radiation therapy 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% (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.)

An extended use of oral contraceptives (the Pill) later in life is also sometimes considered a factor for developing breast cancer. However, this is still subject to much debate in the medical community.

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