SAN FRANCISCO - Advances in interventional biopsy techniques are helping to take the diagnosis of small breast cancers out of the operating room and into a minimally invasive, non-surgical therapeutic setting, said Dr. Steve Parker at a presentation this week at the American College of Radiology's National Conference on Breast Cancer.
Parker, director of the Sally Jobe Breast Center in Englewood, CO, discussed the most recent improvements in percutaneous intervention on April 11, the final day of the NCBC conference. Parker outlined the advantages of both vacuum-assisted biopsy, as well as experimental instruments that employ radio-frequency energy.
Parker disclosed that he is a major in shareholder in Johnson & Johnson, whose Ethicon Endo-Surgery unit in Cincinnati, OH, manufactures the Mammotome breast biopsy device. Parker is also a shareholder in two other interventional instrument makers, UltraGuide of Haifa, Israel, and SenoRx of Irvine, CA.
Products in the works
Two experimental devices that Parker highlighted were SenoRx’s EasyGuide, an introducer sheath, and AnchorGuide, a multiwire localization device, both of which are radio-frequency based.
"We’re just now investigating these devices that, hopefully, will be part of our armamentarium in the near future. These devices are not yet FDA-approved and we’re waiting on the completion of some studies," Parker said.
The main benefit of EasyGuide is its ability to advance smoothly through all types of tissue, whether it’s dense, fibrous, or fat, Parker said. EasyGuide gives clinicians a "working port" into the breast, making it possible for a Mammotome biopsy to progress without the need for continuous real-time observation.
"You get it in there and it’s in the right position to proceed with your ultrasound-guided Mammotome biopsy," he said.
The distinguishing feature of AnchorGuide is that it eliminates some of the problems associated with traditional needle hook wires, which can deflect and bend. Made up of multiple wires, AnchorGuide deploys in opposite directions and surrounds the lesion within a 3-cm circumference. Surgeons have found it useful as a retractor to bring the lesion into view, as well as to reposition a non-palpable lesion into a palpable position. While the instrument is easy to get in, taking it out can be tricky, Parker said.
"Because these wires fan out in opposite directions, it’s very difficult to dislodge this thing," he explained. "You can almost pick the patient right up off the table."
Mastering the Mammotome
In terms of conquering small lesions, Parker said the weapon of choice is the hand-held Mammotome. First introduced five years ago, the 11-gauge Mammotome device is especially useful for tackling microcalcifications and masses less than 1.5 cm in size.
Guided by ultrasound, Mammotome allows for a greater amount of breast tissue to be harvested in a shorter amount of time. The tissue also is obtained contiguously, insuring that all of the targeted biopsy area is sampled. One of the advantages of Mammotome is the reduction in the number of false negatives that occur with standard core biopsy, Parker said.
"I don’t think there’s any reason to use the Mammotome for masses larger than 1.5 cm. The reason I say that is because when we look at our core biopsy date, we’ve had zero false negatives for masses greater than 1 cm. The place where we have false negatives with traditional core biopsy is with microcalcification cases and masses smaller than 1.5 cm. If you have a zero tolerance for false negatives, which is how I approach it, use the Mammotome for small masses," he said.
Parker also described the device as ideal for the percutaneous removal of benign papillomas. In his practice, when benign interductal papillomas are removed, ductal discharge is taken care of as well.
"In this particular instance, it’s not just a diagnostic procedure, but also therapeutic," he said.
Finally, Parker discussed UltraGuide, a device that is well suited for clinicians who are not comfortable with ultrasound guidance. Using a small magnetic field, UltraGuide detects the relative position of the needle to the transducer and generates the expected pathway of the needle. A digital readout shows how many millimeters from the lesion the needle is placed.
Future uses of these new interventional instruments could include in situ ablation with stereotactic or MRI-guided laser therapy, as well as ultrasound-guided cryotherapy.
By Shalmali Pal
AuntMinnie.com staff writer
April 13, 2000
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