Breast cancer is the number two type of cancer in U.S. women. (Skin cancer is number one.) As a result, doctors and researchers have developed better diagnostic methods and treatments. Because early detection is so important in fighting breast cancer, staying informed can be a powerful defense.

  The National Cancer Institute offers excellent information on breast cancer risk factors, common symptoms and mammogram recommendations.

  The risk of developing breast cancer is not the same for all women. Because breast cancer is most common in women over 50, the greatest risk is growing older. The following factors also are known to increase a woman's risk:

• Personal history - Women who have had breast cancer have a greater chance of developing a second breast cancer.
• Family history - The risk of getting breast cancer is higher for a woman whose mother, sister, or daughter has had the disease; or who has two or more close relatives, such as cousins or aunts, with a history of breast cancer (especially if diagnosed before age 40). About 5 percent of women with breast cancer have a hereditary form of the disease.
• Genetic alterations - Specific alterations in certain genes, such as those in the breast cancer genes BRCA1 or BRCA2, make women more susceptible to breast cancer. Gene testing is available to help detect these genetic alterations.

These other factors have been linked to an increased risk:

• Estrogen - Women who began menstruating before age 12, began menopause after age 55, never had children, or took hormone replacement drugs for long periods are more likely to get breast cancer.
• Dense breast tissue - Women who have a larger proportion of dense breast tissue compared to fatty tissue are at elevated risk. (This is not only because tumors in dense breasts are harder to see on mammograms, but also because dense breast tissue itself is related to an increased chance of breast cancer.) 
• Postponed childbearing - A woman who has her first child after age 30 has an increased risk.
• Radiation treatment - Women whose breasts were exposed to radiation during treatment for Hodgkin's, or other diseases, before age 30 are at an increased risk.
• Alcohol - Some studies show women who drink alcohol to be at a slightly higher risk.

  Although early breast cancer is usually painless and symptom-free, the following symptoms could appear as the cancer grows:

• A lump or thickening in the breast or surrounding tissue
• A change in breast size or shape
• A change in the nipple such as tenderness, discharge or sinking into the breast
• Rippling or pitting of breast skin (similar to the skin of an orange)
• A change in look or feel such as increased warmth, swelling, redness or scaling

  A screening mammogram is an X-ray of the breast used to detect breast changes in women who have no signs of breast cancer. It usually involves two X-rays of each breast. Using a mammogram, it is possible to detect a tumor that cannot be felt. 

  A diagnostic mammogram is an X-ray of the breast used to diagnose unusual breast changes, such as a lump, pain, nipple thickening or discharge, or a change in breast size or shape. Also, a diagnostic mammogram is used to evaluate abnormalities detected on a screening mammogram. It is a basic medical tool and is appropriate in the workup of breast changes regardless of a woman's age.

  The National Cancer Institute recommends that women in their forties or older get screening mammograms every one to two years.

  Women at increased risk for breast cancer should seek medical advice about when to begin and how often to have mammograms. For example, a doctor may recommend that a woman at increased risk begin screening before age 40 or schedule her screenings on a more frequent basis.