One risk factor for breast cancer is hormone stimulation. One way to stimulate hormones is hormone replacement therapy. Hormone replacement therapy was a popular treatment for women going through menopause. It was used to control the mood swings and other menopause symptoms. The hormone commonly being replaced was estrogen, with progesterone sometimes being used as well. The greatest risk comes from using a combination of progesterone and estrogen.

One other way for hormone stimulation is an uncontrollable factor, the age a woman begins menstruation and menopause. If a girl starts menstruation before 12, or a woman starts menopause before age 55, she will have an increased risk of developing breast cancer. There are ways to decrease that risk though. If a woman has a full-term pregnancy (38 to 40 weeks) before the age of 30 that may decrease her risk. Also, if a woman breast feeds her infant for at least 12 months or breast feeds several children, her risk may also be reduced.

Medication can also be used to prevent breast cancer. Tamoxifen is the most commonly used and others are being researched right now for their potential use in preventing breast cancer. Tamoxifen is often prescribed to women who have an increased risk of developing breast cancer, either because of genetic factors or other risk factors. This medication works by blocking how estrogen affects the cells in your breast. There are several serious risks associated with tamoxifen use however. These include an increased risk of uterine cancer, stroke and blood clots in the legs or lungs. You need to see your doctor immediately if you develop any symptom of these side effects.

Some women may choose to surgically remove their breasts in order to prevent breast cancer. This is called a preventive mastectomy. This is usually done by women who have a strong family history of breast cancer, as in several women (usually a woman's mother, sisters and/or aunts) in the family have been diagnosed with breast cancer. This surgery reduces the risk of breast cancer by as much as 90%.

Another type of surgery that may be performed to reduce the risk of breast cancer is a prophylactic oophorectomy, or elective surgery to remove the ovaries. This helps reduce the risk of breast cancer because the hormones produced by the ovaries increases a woman's risk of developing breast cancer. The genetic mutations that increase breast cancer risk may also increase a woman's chances of developing ovarian cancer. By removing her ovaries, a woman can dramatically decrease her chances of developing either type of cancer.

A woman's choice of foods and lifestyle may increase her risk of breast cancer. There seems to be a connection between obesity and breast cancer. Some studies have shown that obese women have a higher chance of developing breast cancer because of an increased amount of estrogen in their systems. Another study has shown that women who regularly eat high-fat foods have an increased risk of dying from breast cancer, not just developing it, compared to women from the same population that eat low-fat foods. These two studies suggest that an exercise program and a low-fat diet may decrease your chances of developing breast cancer. One lifestyle choice that may increase a woman's risk of developing breast cancer is alcohol drinking. Studies have shown that drinking alcohol may slightly increase a woman's risk of developing breast cancer. This does not mean that every woman who had a drink to celebrate her birthday or job promotion is at greater risk of cancer. The study suggested that current drinking had more of an impact on the risk than drinking as a young adult.