As a breast surgeon, every day I speak with women who have been diagnosed with breast cancer or are concerned about their risk of developing breast cancer. For those with breast cancer, many of their questions revolve around what caused their breast cancer and what the implications are for their sisters or daughters. Those who have been told they are at increased risk are also looking for answers and options to reduce their risk.
Risk Factors for Breast Cancer
The average woman’s lifetime risk for breast cancer is roughly 12 percent, meaning approximately one in eight women will develop breast cancer in her lifetime. The challenge is in identifying the “average” woman, as many women have risk factors that place them at higher risk. Some of these risk factors are obvious, like having a family history, while others are not. Accounting for all known risk factors identifies a large group of women that fall into a 20 to 40 percent risk range, while women with certain genetic mutations may have an even higher risk of developing breast cancer.
Primary risk factors for breast cancer include:
- Genetic mutations – Carrying a BRCA1 or BRCA2 mutation puts a woman at a 50 to 80 percent lifetime risk of developing breast cancer. Other genetic mutations also have been implicated in the development of breast cancer, including mutations in p53, CHEK2, ATM, and PALB2. Genetic counseling and testing are recommended for women with a strong family history of breast and/or ovarian cancer to identify the presence of an inherited mutation.
- Family history – Even in the absence of a genetic mutation, women with a family history of breast cancer in a first-degree relative may be two to three times more likely to develop breast cancer.
- Radiation exposure – Those who have had radiation exposure to the chest area in adolescence or young adulthood (before the age of 30), such as for treatment for childhood cancers, acne, or enlarged thymus glands, are at higher risk for developing breast cancer.
- Atypical ductal and lobular hyperplasia (ADH/ALH) and lobular carcinoma in situ (LCIS) – Women who have undergone a biopsy and/or breast surgery that identifies cells growing in an abnormal pattern in the ducts or lobules are at increased risk of developing breast cancer.
- Breast density – Women with extremely dense breasts are four to five times more likely to develop breast cancer than women with non-dense or fatty breasts.
- Obesity and alcohol consumption – Women who are overweight or obese and women who consume more than two to three alcoholic drinks per day have a higher risk of breast cancer.
Assessing Your Risk
Assessing individual risk for breast cancer is complicated. Breast cancer is not just one disease; it is a family of diseases, and the risk factors that can lead to the development of different types of breast cancer also vary. This is why it is important to discuss your individual risk with your doctor or, ideally, a team of breast specialists. At Brigham and Women’s Hospital, for example, we provide personalized risk assessment, screening, and prevention strategies for women at increased risk and for those who want to learn about their risk in our Breast Cancer Personalized Risk Assessment, Education and Prevention (B-PREP) Program.
The B-PREP team includes breast surgeons, medical oncologists, breast imaging specialists, nurse practitioners, social workers and other breast specialists from both Brigham and Women’s and Dana-Farber Cancer Institute (DFCI). I lead this program with Dr. Daniel Morganstern, a medical oncologist in the Clinical Genetics and Breast Oncology Program at DFCI. B-PREP is truly a collaborative program. Depending on your level of risk, your health care providers may suggest additional screening tests and/or more frequent surveillance. To provide comprehensive and seamless care, we work closely with the Cancer Genetics and Prevention Program at DFCI, and we will coordinate and expedite genetic counseling and testing where appropriate. For those interested in lifestyle modifications, including weight loss, we will coordinate and expedite referrals into the Brigham and Women’s Hospital Weight Management Program.
Accounting for all known risk factors identifies a large group of women that fall into a 20 to 40 percent risk range, while women with certain genetic mutations may have an even higher risk of developing breast cancer.
Reducing Your Risk
There are a variety of ways to reduce your risk of developing breast cancer. Healthy lifestyle choices can dramatically reduce your risk of developing breast cancer, as well as other diseases such as heart disease, diabetes, and osteoporosis.
Here are some lifestyle guidelines to consider:
- Exercise regularly
- Maintain a healthy weight
- Select plenty of fruits, vegetables, and whole grains for your diet and limit processed foods, red meat, and saturated and trans fats
- Limit alcohol intake
- Breast feed your baby when possible
- Limit use of menopausal hormone therapy
In some cases, medications to reduce breast cancer risk, participation in a clinical trial, or prophylactic surgery may be considered. Decisions such as these should be made in close collaboration with your health care team, who can discuss the risks and benefits of each approach to prevention.