It is important to realize that while this operation removes nearly all of the breast tissue, a small amount remains. So, while, this operation reduces the risk of breast cancer, it does not guarantee that a cancer will not develop in the small amount of breast tissue remaining after surgery. Second opinions are strongly recommended before any woman makes the decision to have this surgery. Nonetheless, after careful consideration, this might be the right choice for some women. Although we know some of the risk factors that increase a woman's chance of developing breast cancer, we do not yet know what causes most breast cancers.
Research is under way to learn more.
Scientists are making great progress in understanding how certain changes in DNA can cause normal cells to become cancerous. DNA is the chemical that carries the instructions for nearly everything our cells do. However, DNA affects more than our outward appearance. Certain genes that promote cell division are called oncogenes. Others that slow down cell division, or cause cells to die at the right time, are called tumor suppressor genes.