Risk Factors

Over 2.5 million women in the United States today have had some form of breast cancer. Outside of skin cancer, it is the most common type of cancer to affect women, and only lung cancer has a higher mortality rate among women. Unlike other cancers, breast cancer is not linked to certain behaviors or environmental factors, but there are several risk factors to be aware of.

Previous Cancer

A woman who has previously had breast cancer has a higher risk for developing another form of cancer in the same breast or in a different breast. This is not the same as having the previous cancer recur.

Family History

A woman whose mother, daughter or sister developed breast cancer has a higher chance of developing the disease than someone whose direct relatives have not. The risk factor is higher if the relative had cancer in both breasts and was diagnosed before the onset of menopause. There is a lower risk factor if a woman's grandmother, aunt or cousin was diagnosed with breast cancer. However, a significant amount of women who develop breast cancer have no family history of the disease.


The chance of developing breast cancer increases with a woman's age. More than half of the women who are diagnosed with breast cancer are over the age of 55.


Some forms of breast cancer are believed to be caused by gene mutation. Women who have a mutation in the BRCA1 and BRCA2 genes have a significantly higher chance of developing breast cancer. The chance may be as high as 80 percent.

Ethnic Background

Although the reason is not clear, white women have a greater chance of getting breast cancer than women of other races and ethnic backgrounds. However, African-American women are more likely to develop the disease at a younger age, and they also have a higher mortality rate than other ethnic groups. Also, women who are descendants of Ashkenazi Jews have a higher chance of developing the disease.

Previous Abnormal Biopsy

Women who have had previous abnormal breast biopsies and certain breast lesions have an elevated risk factor, even if the biopsies were benign. In addition, women who have been diagnosed with lobular carcinoma in situ, which is not cancerous, have a higher risk of getting breast cancer later on.

Dense Breast Tissue

Women with dense breast tissue have more glandular tissue than fatty tissue in their breasts. This makes it harder to discover abnormalities in a mammogram and increases a woman's chance of developing breast cancer.

Previous Radiation

Women who have previously undergone radiation treatment to their chest area have a greater chance of developing breast cancer. If the women had radiation treatment while their breasts were still developing, the risk factor is greater. The risk is lower if the radiation was done later in life.

Menstrual History

There may be a correlation between the number of menstrual cycles that a woman has had and her chance of developing breast cancer. A woman's risk factor increases if she began menstruating before the age of 12, or entered menopause after turning 55. Women who have experienced a higher number of menstrual cycles have also had a longer exposure to female hormones, and this is the reason for the higher risk factor.

Other Types of Cancer

Women who have had ovarian, uterine, cervical or colon cancer are also at risk for developing breast cancer. There is also a higher risk factor if a close relative has been diagnosed with one of these forms of cancer.

Being Overweight

Women who are overweight tend to have a greater chance of developing the disease, especially if they are older and have more body fat around their waists.

Hormone Therapy

Women who take hormones to help ease the symptoms of menopause and prevent osteoporosis are at risk for developing breast cancer. The risk is higher in women who take a combination of estrogen and progesterone. Those who only take estrogen are at a lower risk for developing breast cancer, although this treatment is only prescribed for women who no longer have a uterus. Women on hormone therapy also tend to have denser breast tissue and may not be diagnosed with cancer in the earliest stages. Additionally, the mortality rate tends to be higher. The risk tends to go down when women are no longer on hormone therapy.

Use of Oral Contraceptives

Taking birth control pills may increase a woman's chances of developing breast cancer. The risk goes down once the pills are discontinued, and there is no increased risk for women who have not taken oral contraceptives in over 10 years.

Number of Pregnancies

Women who have never been pregnant may be at a higher risk for getting breast cancer than women who have borne children. Additionally, women who delivered their first child after age 30 may also have a higher risk than women who had children at a younger age. Women who have delivered several children may have a lower risk for developing the disease. Since menstruation stops during pregnancy, this may explain the decreased risk.

Choosing Not to Breast-feed

Breast-feeding her baby may lower a woman's risk of developing breast cancer later on. Women who breast-feed for over a year may have the lowest risk factor. Lactation usually suppresses menstruation, and this may explain the lower risk factor.

Alcohol Consumption

Women who consume more than two alcoholic drinks every day may have an increased chance of getting breast cancer.

There are still many unknown factors regarding a woman's chance of developing breast cancer. If a woman has concerns about her personal risk factors, she should speak with a medical professional.

Overview & Facts  Signs & Symptoms

Spread The Word

Button For Your Website

Moms I Owe

<a href="http://moms.io"><img src="http://moms.io/assets/button-small.png" alt="Moms I Owe"></a>


Spread The Word

On Social Networks

Via Email

Here's a message you can email everyone on your contact list:

Hey, you need to read how breast cancer is
treatable, if discovered in the early stages:


Use this printable flyer to help spread the message:

Download Flyer

On Your Website

Use these buttons on your website / blog to show your support:

Moms I Owe

<a href="http://moms.io"><img src="http://moms.io/assets/button-large.png" alt="Moms I Owe"></a>

Moms I Owe

<a href="http://moms.io"><img src="http://moms.io/assets/button-small.png" alt="Moms I Owe"></a>

Support Moms I Owe and help prevent breast cancer.

Support <a href="http://moms.io">Moms I Owe</a> and
help prevent breast cancer.