There is significant evidence that negative margins are critical in lumpectomies in order to achieve low rates of recurrence equivalent to mastectomies, as well as equivalent survival rates.1 However, with modern diagnostic methods identifying cancer at much earlier stages, and locating much smaller lesions, and with an increase in DCIS diagnoses, obtaining negative margins is becoming increasingly difficult.
Positive margins—identified by pathologists long after the initial surgery procedure is completed—present numerous medical challenges, as well as emotional challenges for the patient and her family. Second surgeries may not be possible. If they can be performed, there are cosmetic implications, additional exposure to anesthesia risks, and delays in radiation and/or chemotherapy. Additionally, when oncoplastic techniques are used during a lumpectomy, there could be other surgical difficulties if positive margins are confirmed at a later date.
Until now, with most lumpectomies, attempts at intraoperative margin assessment—using palpation, visual inspection, and specimen imaging—are considered less than ideal.
In most cases, positive margins require a second surgical procedure. Depending upon the type of cancer, re-excision rates have run from 22% of lumpectomies2 to 36% and higher when DCIS is present3.
MarginProbe can make a difference
Intraoperative assessment with the MarginProbe System can be performed by surgeons themselves immediately following the removal of tissue from the breast. A sterile, single-use sensor —attached to a handheld probe—delivers a small area radio frequency (RF) signal to the tissue and captures reflected signals. Information from the reflected signals is sent to the MarginProbe console for analysis. Using a proprietary algorithm, comparisons are made to reflected signals from thousands of other tissue specimens. Results are then displayed for the surgeon—either positive or negative for cancer cells on each of six tissue surfaces. The surgeon can then decide, immediately, if additional tissue removal is required.
1. N Engl J Med. 2002;347(16):1233-1241.
2. Expert Rev. Anticancer Ther. 8(8), 1193-1196 (2008), Eur. J. Cancer 39, 932–944 (2003), JAMA. 2012;307(5):467-475
3. Meijnen, Ann Surg Onc (2007) 15(1): 23-243, Mod Path (2008) 21: 39-45
The Probe is a lightweight, sterile, disposable device which the surgeon uses to control contact with the excised tissue. It connects to the Console for both electrical power and to enable the unit to establish a vacuum connection with the tissue specimen. This provides consistency in the amount of pressure applied to the tissue for optimal measurements.
The Fringe Field Sensor is an integrated element of the probe, located at the tip of the instrument. It functions as the heart of the MarginProbe System. On contact with tissue, the sensor delivers an electrical field, then captures the electromagnetic response (reflection) of the examined tissue to distinguish tissue type (normal or malignant). The low-power levels of both the instrument and the RF signals directed to the tissue assure that later examinations by the pathologist will be unaffected.
The Console incorporates a distinct module which enables the Margin Probe System to generate and collect RF signals used for margin analysis. Other modules within the unit provide electric and vacuum control, data processing and information display. A proprietary algorithm housed within the Console analyzes the bioelectric signatures from the tumor, and then compares those signatures to thousands of others in the MarginProbe database.
We’re interested in hearing from you
More and more breast surgeons are interested in the details of the MarginProbe System for intraoperative margin assessment. If you’d like to know more about the technology and the science behind it, contact us. We’ll be happy to provide more information or have one of our sales representatives contact you directly to schedule a product presentation.