Ductal lavage, an advanced technique for collecting epithelial cells from the breast milk ducts for cytologic examination, enables the detection of premalignant and malignant cells in women who have had normal mammograms and physical exams. That is the preliminary finding of a new multicenter clinical trial presented at the annual scientific meeting of the American Society of Clinical Oncologists (ASCO) in New Orleans.
All breast cancer begins in the milk ductal system of the breast. Ductal lavage collects breast cells directly from the milk ducts, where breast cancer originates, said Joyce OShaughnessy, MD, director of chemoprevention research at US Oncology and director of cancer prevention at Baylor-Sammons Cancer Center in Dallas, one of the sites participating in the recent clinical trial.
The minimally invasive ductal lavage procedure functions somewhat like a Pap smear for the breast. By collecting and allowing the early determination of premalignant and malignant cells from their source, ductal lavage gives physicians both additional information and time to counsel women about their management and therapeutic options.
The prospective, multicenter clinical trial was conducted in one European clinic and 20 sites in the United States. It included 495 women, with tests on 532 breasts. The women were determined to be at high risk for breast cancerthat is, they scored a minimum of 1.7 on the Gail index, had previous breast cancer, or carried mutations in the BRCA1 or BRCA2 gene. Investigators required the women to have normal mammograms and physical exams within 12 months of entering the study in order to see if ductal lavage might identify cellular abnormalities not detected by other standard breast diagnostic tests.
As of May 2000, ductal lavage determined the presence of abnormal breast epithelial cells in 15% (41/271) of the high-risk women for whom results were analyzed; 4% (11/271) were found to have markedly abnormal cells in their breasts. Ductal lavage found atypical breast cells in 11% of these women.
Medical follow-up is still in progress. In one case, a 2-cm malignancy was identified in a woman who had normal mammograms both before and after the ductal lavage procedure. By identifying the milk duct in which the malignancy was located, ductal lavage enabled surgeons to remove the malignancy with an excisional biopsy.
In the clinical trial, we were able to identify cell abnormalities that place a woman at higher risk for developing cancer before any indication could be seen on a mammogram or be felt during a physical exam, said Dr OShaughnessy. With this new procedure, I believe we can detect early abnormalities in breast cells before they become cancerous.
Currently, no other minimally invasive procedure allows the detection and localization of premalignant or malignant cells directly at the source of breast cancer, and at such an early stage, she added.
The procedure proved easy to learn, comfortable for the women being tested, and safe. A manual breast pump (Pro·Duct Breast Aspirator) was used to draw fluid from the nipple and identify which milk ducts to lavage. Previous research had demonstrated that nipple aspirate fluid production upon nipple aspiration is associated with roughly a doubling in breast cancer risk.
To perform the ductal lavage procedure, a flexible microcatheter (Pro·Duct Catheter) was inserted approximately ½ inch into the fluid-producing ducts through the natural nipple opening. A small amount of saline solution is introduced, washing cells out of the lining of the ducts. These cells are collected and analyzed, similar to a Pap smear.