New Milk Duct Test May Detect Breast Cancer Earlier
April 26, 2001 -- A new breast cancer test that examines breast cells taken from the milk ducts sometimes can detect the disease earlier than mammography, the gold standard screening tool.
Though mammography is the most widely used screening tool for breast cancer, it does not detect all early breast cancer and is especially likely to miss small tumors in young women with dense breasts. Thus, researchers are looking for other screening tools to use alongside mammography.
The milk duct test, described in the April 28 issue of The Lancet,may be such a tool. That's because breast cancer often starts in the cells that line the milk ducts, study author Saraswati Sukumar, PhD tells WebMD.
In the milk duct test, called ductal lavage, the ducts are washed out with a saline solution that is injected through the nipple. The flushing loosens breast cells that are then withdrawn out again with the solution. The cells are then examined under the microscope. Women who have undergone ductal lavage say the procedure is uncomfortable but not painful.
Sukumar is senior investigator of a research project examining a new way to evaluate the cells obtained via ductal lavage as well as an associate professor of oncology and pathology and director of basic research at the Breast Cancer Program of the Johns Hopkins Oncology Center in Baltimore.
In the study, Sukumar and colleagues report that by looking for genetic abnormalities in the cells collected via ductal lavage, they were able to identify breast cancer in its very early stages with remarkable accuracy. They also were able to detect when cancer was not present.
Breast cancer specialist David Euhus, MD, says ductal lavage will not be a good method of screening all women for breast cancer -- the way mammography is used. One reason is that the lavage method only collects cells from a few of the 30 or so ducts in the breast, so it is easy to miss cancer. Another problem is that the procedure takes time and is quite expensive to perform. According to Euhus, who runs a high-risk clinic for breast cancer at the University of Texas Southwestern Medical Center at Dallas, the milk duct test will be most helpful in detecting disease in women known to be at high risk for breast cancer because of other factors, such as family history.
Euhus says that using the technique described by Sukumar and his colleagues, called a methylation test, to examine the cells obtained via ductal lavage is an extremely important advance. He explains that methylation is simply a process used by cells in the body when they are making copies of themselves. He and others have found that cancerous cells have far more methylation than normal cells do, so looking for methylation in breast cells offers an objective way of assessing whether the cells are likely to be cancerous.
Though ductal lavage will never be suited for screening all women, just those known to have risk factors for the disease, Euhus believes this new methylation technique to examine milk duct cells will probably become a very important tool for detecting early breast cancer. He also suspects that other researchers will not be able to obtain the remarkable accuracy that Sukumar and his colleagues report, but even if it is slightly less accurate, a tool like this would be an important advance in the battle against breast cancer.
Although additional studies must be done to confirm his findings, Sukumar hopes that this new way of examining cells obtained from ductal lavage will be widely available within two to three years.