How do most breast cancers develop?

Most breast cancers (about 95 percent) develop in specialized cells called epithelial cells that line the milk ducts of the breast. Each breast has 6 to 9 separate ducts, which function independently of each other. Cancer that begins in one duct may be contained to that duct if caught early, making treatment more effective and increasing survival. By the time cancer is detected, however, it often has progressed beyond a single duct. (Experts estimate that it takes 8 to 10 years for cancer to grow from 1 cell to a mass large enough to be detected on a mammogram—about 1 billion cells.) Current research is seeking ways to identify women at highest risk for breast cancer so that proactive risk management may be started to help prevent the development of breast cancer.

What is ductal lavage?

Ductal lavage is a procedure for collecting cells from the milk ducts of the breast for analysis. The procedure is used to identify cells in a pre-cancer stage, called atypical cells. Ductal lavage currently is performed on women who have multiple risk factors for breast cancer. (A risk factor is a condition or behavior that puts a person at risk for developing a disease.)

Ductal lavage is a minimally invasive procedure that may be performed in a doctor’s office or outpatient center. It is performed in three steps:

  • Step 1 — An anesthetic cream is applied to numb the nipple area. Gentle suction is used to withdraw a small amount of fluid from the milk ducts. This is done to locate the opening of the ducts on the nipple’s surface and to identify ducts to be tested. Ducts that do not produce fluid generally are not tested with the lavage procedure, since atypical cells are more commonly found in ducts that produce fluid.
  • Step 2 — A hair-thin catheter (small tube) is inserted into the natural opening of the duct. Additional anesthetic is delivered into the duct. A saline (salt and water) solution is then infused through the catheter to rinse the duct, which loosens cells from the duct lining. The solution containing the loosened cells is withdrawn through the catheter. (The word "lavage" is French for "wash" or "rinse.")
  • Step 3 — The sample is sent to the laboratory for analysis to determine if the cells are normal or abnormal (atypical cells). Women with atypical cells have an increased risk of developing breast cancer.

Who is a candidate for ductal lavage?

Ductal lavage is recommended only for women who are at high risk for breast cancer. There are several factors that put a woman at high risk for developing breast cancer, including:

  • A personal history of breast cancer
  • A family history of breast cancer, particularly in a mother, daughter or sister
  • Evidence of a specific gene (BRCA1/BRCA2 mutation)
  • A Gail Index score of at least 1.7 percent (The Gail Index uses risk factors such as age, family history of breast cancer, age of first menstrual period and first pregnancy, and number of breast biopsies to calculate a woman’s risk of developing breast cancer within the next five years.)