1. Breast Cancer Slideshow Pictures
2. Take the Breast Cancer Quiz
3. Disease Prevention in Women Slideshow Pictures

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View Full Profile

In this Article

• Introduction to breast cancer prevention
• What are the biological causes of breast cancer?
• What are the risk factors for developing breast cancer?
• What is the importance of early breast cancer detection?
• What are the advantages and limitations of mammography?
• How frequently should women undergo mammography and breast examinations?
• What is the risk of radiation with repeated mammography screening over the years?
• Are there any controversies in the area of breast cancer screening?
• How helpful are BRCA1 and BRCA2 genetic tests in identifying women at risk?
• What is the link between estrogen and breast cancer?
• What are breast cancer prevention treatments?
• Are there other breast cancer prevention measures?
• Conclusion
• Breast Cancer Prevention Index

Antioxidants

Antioxidants are chemicals that prevent a type of chemical reaction called oxidation. Oxidation is a major source of free radical formation. Antioxidants also mop up the free radicals that are formed.

Free radicals are electrically charged chemicals that can attack and damage proteins and DNA, thereby altering genetic information. If enough damage occurs to the DNA segments of a cell that controls cell division and growth, cancer can develop from that single cell. Free radicals can be formed by the normal metabolic activity in the body.

Free radicals also occur when cells are exposed to radiation. The body is regularly exposed to low levels of radiation in the atmosphere. The body also receives radiation during mammography and other X-ray tests. Theoretically, these low levels of radiation can lead to the formation of free radicals. (The amount of radiation in the atmosphere and in carefully performed X-rays tests is generally considered safe.)

Fortunately, a healthy body is well equipped to destroy free radicals and prevent cells with damaged DNA from becoming cancerous. The body is capable of quickly recognizing and destroying free radicals. For example, the body has an enzyme called superoxide dismutase that regularly cleans up free radicals and prevents them from damaging cells and proteins. The body can repair DNA damage caused by radiation or free radicals. The body is also capable of quickly destroying cells that have irreparable DNA damage to prevent them from turning cancerous. The immune system also seeks out cells with DNA damage and destroys them.

Naturally occurring antioxidants include beta carotene, vitamin E, and vitamin C. Fruits and vegetables are safe and rich sources of antioxidants. A somewhat controversial substance is caffeine. In several laboratory studies, caffeine acted like an antioxidant that cleans up free radicals. At present, there is no evidence that caffeine or coffee affects breast cancer risk. Also, some caffeine-containing substances, such as tea, have apparently been shown to decrease cancer risks.

Dietary fats

Early epidemiological studies suggested that high-fat diets might be associated with increased risks of breast cancer. But this relationship has not been confirmed, and results of studies have been mixed. Furthermore, it is clear that some fats may be protective rather than harmful. There are, however, some theoretical concerns about eating overcooked meats and fats.

Diet and lifestyle measures to reduce breast cancer risk

Theoretically, there are dietary and lifestyle measures that can decrease free-radical formation and reduce the risk of developing breast and other types of cancer. These measures include

• diets rich in vegetables and fruits;
• diets low in fats, and red and overcooked meats;
• reasonable intake of antioxidants, such as vitamins E and C;
• regular exercise and weight reduction;
• avoiding cigarettes.

Evidence that these measures reduce the chances of developing breast cancer is largely based on epidemiological data. Epidemiological evidence is derived from comparing two large populations with similar characteristics that have different diets or levels of exercise. Epidemiological evidence can only be suggestive, not conclusive. In fact, concrete proof that diet and exercise actually reduce the risk of developing breast cancer will be difficult to attain.

When firm scientific data is lacking and is unlikely to be available for the foreseeable future, the doctor has to weigh the risks of his/her recommendations against the potential benefits. Long-term risk and benefit considerations are especially important in advising young, healthy women about preventing a disease that they may or may not develop.

In the case of diets low in fat and overcooked meats, diets high in vegetables and fruits, avoiding smoking, and regular exercise, there is enough known benefit and very little known risk, which makes it easy for doctors to recommend them to their patients.

Doctors are also comfortable with recommending one multivitamin a day. However, there is no clinical evidence that taking megadoses of vitamins are of any benefit. Megadoses of certain vitamins can have adverse side effects.

Exercise

There is epidemiological data which show that women who exercise regularly have a lower incidence of breast cancer than women who do not exercise. The reason for such a benefit is unknown, but it may be related to the fact that obese individuals have higher levels of estrogen in the body than nonobese people. The higher levels of estrogen may increase the risk of breast cancer in obese women.