First ever mammary ductoscopy performed in Canada

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This summer, physicians at Toronto’s Princess Margaret Hospital – Canada’s premier cancer hospital – used a very small scope to peer into the milk duct lining of a woman’s breast through her nipple. This is significant for two reasons. One, Canadian doctors can now see where 80 per cent of breast cancers begin and two, the procedure marked the first time a mammary ductoscopy had ever been performed in Canada.

“We are thrilled to be the first to bring this technology to Canada,” Dr. Wey Leong, Surgical Oncologist at Princess Margaret Hospital said. “It is everything we expected and more.” Mammary ductoscopy – a non-invasive procedure that has been used in Japan and Europe for several years – allows surgeons a glimpse of an area that was, until now, a dark crevice only reachable by invasive surgery.

Mammary ductoscopy allows doctors to receive a more complete and clear picture than is now available from the standard methods of mammograms and ultrasound. “Since most breast cancers and many benign breast tumours arise from the lining of the milk duct, we hope to detect early changes in breast cancer or warning signs of it before they become a real problem,” Dr. Leong said. This is possible because the ductoscope can penetrate the milk ducts whereas the mammogram, x-rays and ultrasound waves cannot.

The ductoscope, which was purchased by funds from the Princess Margaret Hospital Foundation, is a small rod that is 0.7 to 0.9 millimetres in diameter and 6 centimetres long, with a camera in the tip. Fluid is released and the breast tissue is massaged, to allow the duct to dilate for easy maneuvering. The scope is attached to a monitor that allows the surgeon to see the duct lining at 60 times its normal size. The total time for mammary ductoscopy is between 30 to 45 minutes. The procedure is very similar to the colonoscopy and the endoscopy.

The direct access to milk ducts, due to uniqueness of the scope, is very important for the early detection and treatment of cancer without being invasive. The procedure gives physicians the ability to retrieve samples of fluid flushed into the ducts that can be cataloged by videotape and studied.

Dr. Leong indicates that the procedure will not eliminate surgery altogether. “When it comes to breast cancer, we are not at that stage to comfortably remove the tumour inside the duct without surgery,” he said. “This may change if we can be more accurate with the diagnosis using the scope and have a very effective way to kill those cancer cells, like photodynamic therapy or delivering [treatment] right to the tumours.”

While mammary ductoscopy may be used as a diagnostic tool in the future, the mammogram is still the standard for early breast cancer detection. However, it is not always the perfect method of detection. Therefore, mammary ductoscopy is seen as complement to the standard. The procedure can be very helpful for diagnosing or investigating women with a high risk of developing breast cancer and is ideally suited for patients with nipple discharge since it is the largest grouping of at risk breast cancer patients. “Although only five per cent of patients with nipple discharge have breast cancers, ruling out breast cancer is still the main reason to operate on these patients,” said Dr. Leong. “If we confirm that the cause is a benign one, we can remove the problem, usually a benign papilloma or polyp inside the duct, using the scope.” Papillomas in the milk ducts need to be removed because they can potentially cause problems in the future.

Physicians at Princess Margaret Hospital, including Dr. Leong, are currently using mammary ductoscopy as a primarily research tool with hopes of using it as a clinical tool in the future. The biopsy that surgeons will be able to perform using the ductoscope also makes it possible for scientists to determine the genetic and chemical changes of these duct cells (cancerous) without worrying about results being contaminated by changes that occur in other cell types outside of the ducts. The biopsy will help us to understand how breast cancers are formed. Dr. Leong believes that mammary ductoscopy will bring much to the future of breast cancer research and treatment. He says that as more technology is developed, surgeons will be able to bring light to the surfaces of live breast cancer, which may give doctors the opportunity to combine light and fluorescence properties to diagnose more accurately.

Dr. Leong says “the most unique feature of the ductoscope is it allows us to look at the part of the breast (inside the duct) where it counts the most.” This is positive news for the estimated 21,500 women that will be diagnosed with breast cancer this year and the 5200 that will die from the disease. Mammary ductoscopy is a procedure that could revolutionize the diagnosis of breast cancer in the future. It may make it possible to prescribe drugs that can treat pre-cancerous tumors. It could also offer targeted therapeutic options including treatment and cancer prevention.