GAITHERSBURG, MD. – A novel radiofrequency probe is one step closer to the operating room to help surgeons ensure that lumpectomy margins are benign.
At a meeting on June 21, the Food and Drug Administration’s General and Plastic Surgery Devices Panel of the Medical Devices Advisory Committee voted 10-1 that the benefits of the MarginProbe system outweigh risks when used as an adjunctive diagnostic tool for the identification of cancerous tissue at the margins of the ex vivo lumpectomy specimen following primary excision in women previously diagnosed with breast cancer.
"I think that it has the potential to be beneficial to women to reduce their chances of going back to the operating room," said panel member Dr. A. Marilyn Leitch, an oncologic surgeon at the University of Texas Southwestern Medical Center in Dallas. "The sponsor has demonstrated that the device can detect tumor in the margins."
The system uses electromagnetic waves to characterize human tissue in real time, providing surgeons with intraoperative information on the malignancy of the margins of an ex vivo lumpectomy specimen. It is intended for use on freshly excised tissue within 20 minutes of excision. The probe is designed to characterize tissue, based on the principles of dielectric spectroscopy, according to a written statement by the company that sponsors the MarginProbe system, Dune Medical Devices Inc.
The sensor generates radiofrequency electromagnetic fields and measures a slice of tissue 7 mm in diameter, a few mm deep and adjacent to the sensor. The resonance characteristics are dependent on tissue properties – malignant tissue has been shown to have different characteristics compared with benign tissue.
The system is intended for intraoperative use in conjunction with standard methods, such as intraoperative imaging and palpation, to increase the likelihood that patients will undergo intraoperative re-excision of the lumpectomy cavity. The locations of re-excision will correspond to the margins of the ex vivo specimen that have less than 1-mm separation of the excision surface of the margin and the primary breast cancer, according to a statement by the company.
Dune Medical Devices is seeking premarket approval of the device based on data from several clinical trials and intended-use trials conducted primarily in Israel but also in the United States.
The FDA asked the General and Plastic Surgery Devices Panel of the Medical Devices Advisory Committee to vote on three questions:
• Is there reasonable assurance that the MarginProbe system is safe for use in patients who meet the criteria specified in the proposed indication?
• Is there reasonable assurance that the MarginProbe is effective for use in for patients who meet the criteria specified in the proposed indication?
• Do the benefits of the MarginProbe for use in patients who meet the specified criteria outweigh the risks for use in this patient populations?
Eleven panel members voted that the device is safe; there was one abstention. Eight panel members voted that the device was effective with regard to the proposed indication; one member voted no and there were two abstentions.
The agency also posed a number of questions to the panel regarding the adequacy of end points of key trials submitted; device sensitivity/specificity; the effect of specimen volume on future cosmesis; the appropriateness of applying the design dataset (based primarily on Israeli patients) to a U.S. population; and suggestions for the sponsor’s proposed postapproval study.
The FDA usually follows the recommendations of its advisory panels, which are not binding.