Jacqueline Eghrari-Sabet: Cancer in general is an abnormal growth of the cells. Breast cancer itself is an abnormal growth of cells that starts in the lining of the milk duct system. Cancers can accumulate to form masses and we call those tumors and cancer in the breast can't really hurt you. It's when cancer spreads outside of the breast that it can do harm to someone.

When it spreads outside the breast, we call that metastasis. The most common type of cancer that we find in the breast is something called Invasive Ductal Carcinoma. It's cancer, that's broken out of the duct.

With mammography, we like to find it one step earlier when it's still in the duct system and we call that Ductal Carcinoma in situ. There are other less common forms of breast cancer but those are the two most common that we find.

As far as who gets breast cancer? Well, it's really a disease of women. A small number occurred in men and there are about a thousand cases nationwide. But it's vastly a disease limited to women.

So in addition to being a women, another risk factor is age. It's a disease that your risk increases as you get older. Infact about two thirds of cases of breast cancer occur in women over 55 years of age.

However, it's important to know that the most years of life lost to breast cancer occurred in women who are in their 40s. So we don't want to forget to start annual screening beginning at age 40 annually. It's an important subset of individuals we tend to forget about. So annual screening beginning at age 40.

As far as who else can get breast cancer. There are the people that have high risk factors. Some of you may have heard about a genetic predisposition. Some people have inherited breast cancers. Fortunately that only accounts for about 10% of breast cancer that we encounter.

But those women have probably up to a 50% to 80% chance of getting breast cancer in their lifetime. Other associated risk factors include women with a history of abnormal biopsy something called Lobular Carcinoma in situ or an atypical hyperplasia. So if you have what's been regarded as a benign biopsy but it has some funny cellular features, you may be at an increased risk of breast cancer over the normal population.

Other risk factors that are associated with breast cancer can include an addition to advancing age, early menstrual cycles. Going through menopause later in life, we think that prolonged exposure to estrogen may slightly increase your risk of breast cancer.

There are so small possible association with hormone replacement therapy or even oral contraceptives although that's a bit controversial and there are other issues such as lifestyle. Obesity, alcohol and lack of exercise may be associated small increased risk factors.

The important thing to remember is that the most important risk factor is simply being a women because 75% of breast cancers occur in women who have no other risk factors other than being a women.