The Multiple Promise of Ductal Lavage

The development of any new procedure that would help detect breast cancer earlier would be exciting. And if that same procedure could detect premalignant breast changes that might be caught before they turned into breast cancer, it would be considered a godsend. And if it could also possibly provide the key to understanding the biologic mechanism of breast cancer, it would be revolutionary.

That new procedure, known as ductal lavage, is currently being studied in an 18-center trial across the U.S. and western Europe. Ductal lavage allows pathologists to retrieve and examine cells that line the milk ducts inside the breast. Since breast cancer starts in these lining cells, this is the single best place to find cancer or pre-cancerous cells in their earliest stages. The procedure involves several steps, and although it sounds like some medieval torture technique, 82% of women who have been through it report that it is equal to or less painful than a mammogram:

• First, a gentle facial-type scrub is rubbed on the nipples to remove the layer of hardened skin called keratin.

• Second, a local anesthetic cream is rubbed on to numb the nipple.

• Third, a nursing pump is used on the breast to try to draw out fluid. This not only allows the physician to see the opening to the milk duct on the outside of the nipple, but scientists believe that ducts that produce fluid are more likely to contain premalignant changes, so they are the ones that it is important to lavage or wash out.

• Next, the physician inserts a tiny tube called a cannula into any duct that produces fluid. (If more than one duct produces fluid, the procedure is done on each duct.) These cannulas are about the size of the minuscule tubes used in a premature infant's IV.

• Through the cannula, a small amount of anesthetic is injected, followed by a little saline water. The breast is massaged to wash the saline around in the ducts. Then more saline in injected. Depending on the side of the ductal system, anywhere from 5 to 40 cc (about 1 to 8 teaspoons) of saline will ultimately be injected into the breast. The goal is to fill the entire ductal system, wash out the duct, and then examine the cells that are sloughed off the inner lining when the saline drains out of the nipple on its own. The entire procedure takes about 30 minutes.

In the current study, women at high risk for breast cancer (defined as having had a previous breast cancer in a contralateral breast or a 1.7 % risk of developing breast cancer within the next five years as measured by the Gail Model) but who had no clinical or mammographic signs of breast cancer received ductal lavage. Although the data are still being collected and analyzed, preliminary results show that atypical cells were found in the saline wash from the lavage in 20% of the women. (Fifteen percent showed mild atypia, 4% showed severe atypia, and 1% had malignant cells.) Based on past experience, about half of the women with severe atypia will have cancer, and about 15 or 20% of the women with mild atypia will have cancer.

What this means is that ductal lavage was able to identify cancer in about 5% of the high-risk women who had normal mammograms. In addition, precancerous warning signs were detected in the other 15%. These are women who had no other symptoms, and normal mammograms. So instead of allowing an undetected cancer to continue to grow, the 5% who had actual cancer will be able to be treated early in its development. And women with premalignant cells may find that by taking chemoprevention drugs, such as tamoxifen or raloxifene, they may be able to reverse the cellular changes and actually prevent cancer.

As exciting as ductal lavage is for individual women, the procedure holds even greater promise for finally revealing the mystery of the mechanics of breast cancer. No one has ever before had access to the premalignant cells that are destined to turn into cancer over time. Lavage may allow scientists to build a model of how breast cancer develops and then know the sequence of development (just as we know that polyps are a likely first step to development of colon cancer). Once the biologic processes are understood, scientists can develop tests for molecular markers - those tell-tale signs that cancer might be growing - and determine a patient's risk of breast cancer simply by testing fluid taken from the nipple. Then further tests, including ductal lavage, could be done to further define the problem.

The final results of the study will be presented at a major international conference in December, but the preliminary results are so impressive that the FDA has already approved the procedure and materials. It is expected that the physicians involved in the study -- including William C. Dooley, M.D., Director of the Johns Hopkins Breast Center - will begin teaching other physicians and nurse practitioners how to perform ductal lavage before the end of the year. Because of its high cost and experimental status, only women with a very high risk of developing breast cancer will be offered ductal lavage initially. But eventually, once the cost comes down and its value is proved, lavage will likely join the mammogram as a standard screening tool.

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