By James C. Salwitz, MD
Breast cancer will kill more than 450,000 women worldwide this year, and in the United States alone, 232,000 will be newly diagnosed. Two important recent events shift the conversation from disease treatment to prevention. The most public was the stunning statement of actress Angelina Jolie that she had both her breasts removed because she carried a breast cancer gene (BRCA1). This announcement served to greatly increase awareness and discussion of choice in preventing the disease.
Second, was the decision by the U.S. Preventative Services Task Force (USPSTF) to recommend the use of medications for prevention of breast cancer in women who are at increased risk.
Many factors influence breast cancer risk
In order to prevent breast cancer, we must first understand its causes. While we do not know all, we do understand that certain factors increase the chance of getting breast cancer. Some of these risk factors can be reduced through improved lifestyle, but not all.
Most breast cancer occurs not because of known genetic mutations, but because of a combination of risk factors. One important risk factor is increasing age, with most breast cancers occurring in women 55 years of age and older.
Some risk factors include an early age for a first period (start of menses), a late first pregnancy, and no pregnancy at all. Breast-feeding decreases cancer rates. Prescription estrogen replacement, especially after menopause, increases breast cancer risk. The more alcohol a woman drinks, starting even with small amounts, the higher her chance of getting the disease. Obesity and low amounts of exercise increase the chance of developing breast cancer, too.
If a woman has increased breast density on mammogram, this increases the chance of being diagnosed with breast cancer. If a woman has any breast biopsies, particularly if the biopsies showed benign growth of the lining of milk ducts ("proliferation"), this increases risk. Certain benign duct changes, such as hyperplasia or atypia, greatly increase risk. Also, ductal or lobular carcinoma-in-situ (DCIS and LCIS) greatly increase the chance of developing invasive breast cancer.
Finally, family history, even without a defined cancer gene like BRCA1 or BRCA2, increases the likelihood a woman will get breast cancer. Each first-degree relative (mother, sister, daughter) who has breast cancer increases further the chance of breast cancer. The younger the breast cancer occurred, the greater the risk to the patient. More...