What Are the Risk Factors for Developing Breast Cancer?

Breast cancer refers to the uncontrolled growth of cells within the breast. The risk factors for developing breast cancer include age, genetics, family history, personal history, menstrual history, breast density, previous radiation therapy, ethnicity, body weight, physical activity level, reproductive history, alcohol consumption and hormone pill use.

Breast cancer refers to the uncontrolled growth of cells within the breast. Breast cancer is the second most common cancer among women in the US (the first being skin cancer). Although far more common in women, breast cancer can affect men as well. About 250,000 women and 2,300 men are diagnosed with breast cancer each year in the US. Each year, breast cancer kills about 42,000 women and 510 men in the US.

The breasts consist of three main parts: lobules, ducts and connective tissue. The milk-producing glands form the lobules. The milk formed in the lobules is carried to the nipples through tube-like channels called the ducts. The connective tissue consists of fibrous and fatty tissue that surrounds and holds everything together. Breast cancer can be of various types depending on the type of cells from which breast cancer originates. The most common types of breast cancers are invasive ductal carcinoma (breast cancers beginning in the ducts) and invasive lobular carcinoma (breast cancers beginning in the lobules). Other less common types of breast cancers include medullary carcinoma, Paget disease, mucinous carcinoma and inflammatory breast cancer.

Some factors may put you at an increased risk of having breast cancer. It must be noted however, that the presence of risk factors does not mean that you will certainly get breast cancer. Likewise, the absence of risk factors does not mean you are immune to breast cancer. Knowing your risk factors is important because it makes you aware. Awareness can help you seek timely medical help if you notice any signs of breast cancer.

The risk factors for breast cancer may be divided into two main groups: non-modifiable and modifiable risk factors.

Non-modifiable risk factors

These include risk factors that you can do nothing about. They are beyond human control and can’t be changed. They include

• Age: Breast cancer risk increases with age. Most breast cancer cases are diagnosed in women over the age of 50 years old.
• Genetics: Inheriting certain genetic changes (mutations), such as those in BRCA1 and BRCA2 genes, increases breast cancer risk.
• Family history: Breast cancer risk is higher if you have any first-degree relative (parent, child or sibling) with a history of breast or ovarian cancer.
• Personal history: Your chances of having breast cancer are higher if you had breast cancer in the past or if you had certain benign (noncancerous) breast conditions, such as atypical hyperplasia of the breast.
• Menstrual history: Early menarche (first menstrual periods before the age of 12 years old) and late menopause (starting after the age of 55 years old) increase the breast cancer risk.
• Dense breasts: Having dense breasts may increase your risk of breast cancer.
• Previous radiation therapy: Previous radiation therapy to the chest or breasts may make you more likely to get breast cancer.
• Ethnicity: Breast cancer risk is higher in Caucasian women as compared to African-American women, but the latter are more likely to die of the disease.

Besides these risk factors, women who took diethyl stilbesterol, or DES (a drug used to prevent miscarriage between 1940 and 1971), have a slightly increased risk of developing breast cancer. Their daughters are also at a greater risk of the disease.

Modifiable risk factors

These include the risk factors that you can control or change. They include

• Body weight: Breast cancer risk is higher in overweight and obese women than in those who are normal weight.
• Hormone pills: Pills containing both estrogen and progesterone may be taken to manage menopause symptoms or as birth control pills. Their long-term use may be associated with breast cancer.
• Physical activity: Lack of physical activity increases breast cancer risk.
• Reproductive history: Breast cancer risk is higher in women who had their first pregnancy after the age of 30 years old, who did not breastfeed or who never had a full-term pregnancy.
• Alcohol: The greater the alcohol consumption, the higher the breast cancer risk.