Endomag, a medical technology company based in Cambridge, UK and Austin, Texas, has developed the Magseed, a magnetic injectable marker that can be implanted by a radiologist during an imaging procedure, such as during ultrasound or X-ray mammographic procedures. The marker can then assist surgeons to find features of interest in soft tissues. Originally intended and used as a marker for breast tumors (the CE mark approval was covered by Medgadget in September 2017), Endomag recently received FDA clearance for the use of the Magseed as a marker of other soft tissues and for long-term implantation.
The marker is a tiny magnetic seed, smaller than a grain of rice, that a surgeon can detect using the company’s Sentimag instrument, which is a sensitive handheld magnetic probe. To support this extended indication, the marker was evaluated in a variety of soft tissues, including thyroid, lung, and lymph tissue, and the recent clearance means that it is now the only wire-free lesion localization system cleared for implantation into any soft tissue, with no limitation on the length of time it can reside in the tissue prior to surgical removal.
Medgadget had the opportunity to ask Eric Mayes, Endomag CEO, some questions about the concept and the recent FDA clearance.
Conn Hastings, Medgadget: Please tell us a little about how and why Magseed was conceived.
Eric Mayes, Endomag: Magseed was really conceived through customer demand. The Sentimag probe was originally developed to locate the sentinel lymph nodes draining a primary breast tumor in conjunction with a magnetic tracer called Sienna+ (the CE mark approval of Sienna was covered by Medgadget in January 2012). Shortly after the commercial launch of Sentimag and Sienna+, breast surgeons started asking whether Sentimag could help address their dissatisfaction with using localization wires to find impalpable breast lesions. We quickly realized the benefit of providing surgeons with a single instrument that can locate both the tumor and the sentinel lymph nodes, so set about developing Magseed to work with our existing Sentimag surgical guidance system.
Medgadget: Can you tell us how Magseed has helped to date with lesion localization in breast cancer?
Eric Mayes: The first clinical users of Magseed for breast lesion localization were surgeons and radiologists at the University of California, San Francisco. Within two weeks of its introduction, all five surgeons and the radiology team decided to adopt it as their standard of care for lesion localization. One reason for their rapid adoption is that localization wires are so problematic. Wires can become dislodged between the time they are placed by the radiologist and when they are removed by the surgeon. This means the surgeon may not remove the tumor in one piece with adequate margins, requiring follow-up surgery at additional cost to the healthcare provider and stress to the patient. To minimize the risk of movement, wires are placed on the same day as surgery, meaning that surgeons must wait on the radiologists which limits the number of procedures possible on a day. Since that first evaluation at UCSF, we have seen a similar adoption response across a number of hospitals and hospital systems with many thousands of successful procedures to date.
Medgadget: How and when is Magseed implanted? Is this a minimally invasive procedure?
Eric Mayes: Magseed is 60% smaller than other non-radioactive lesion localization markers and, prior to this new 510(k) clearance, Magseed could be implanted up to 30 days in advance of surgery. Now it can be implanted at any time in advance of surgical removal, freeing clinicians from the regulatory distinction between prolonged and long-term implantation. Typically, a Magseed marker is implanted by the Radiology department using ultrasound or mammographic imaging to locate the tumor, and then deploying the Magseed into the center using a very fine, 18-Gauge needle. Once implanted, the Magseed is set firmly in place and the patient is free to return home and carry on their usual daily activities until surgery.
Medgadget: The indication extension allows for implantation in any soft tissue. Is this a paradigm shift in how Magseed will be used? What sort of features might radiologists highlight using the probe?
Eric Mayes: Once Magseed was cleared and in clinical use, surgeons started asking whether they could use it in new ways. This wasn’t limited to breast surgeons and included surgical oncologists from multiple specialties inquiring about the potential to mark other cancerous lesions for removal. To support the extended indication for Magseed, we evaluated it in a variety of soft tissues including lymphatic, lung and thyroid to demonstrate the safety of usage in these new contexts. This recent clearance has generated a significant buzz in advance of the Society of Surgical Oncology’s annual conference later this month in Chicago.
Just as the Sienna+ tracer has an open indication for locating sentinel lymph nodes in Europe, where surgeons have demonstrated the clinical value for patients with melanoma, prostate, endometrial tumors and more, Magseed in the US now has the potential to help localize a wider variety of tumors.
Medgadget: The indication extension also permits for long-term implantation. When might this be required, and what are the advantages of being able to leave the device in place?
Eric Mayes: As mentioned, the Magseed marker now frees clinicians from the regulatory distinction between prolonged and long-term implantation. Many surgeons have expressed their desire to mark a tumor greater than 30 days in advance for a number of reasons from scheduling convenience, to wanting to spare patients an additional visit to the hospital, and to wanting to observe tissue over a greater span of time prior to its removal. We expect to see this expanded indication opening a number of new clinical uses for the entire Sentimag surgical guidance system.
Medgadget: How robust is the Magseed? Is there a risk that the device could be broken during deployment or surgery?
Eric Mayes: In comparison with other wire-free tumor localization systems, the strength of the Magseed marker is that it’s made of a single magnetizable material that is robust and durable. It doesn’t rely on electronic circuitry that could fail or be damaged. The hard work is being done by the Sentimag probe which temporarily magnetizes and senses the marker. Once implanted, the seed sits firmly in place and doesn’t move during implantation. During surgery the marker is detectable from any direction and is unaffected by electrocautery systems or halogen OR lights. The Sentimag is actually a quantitative instrument so, even if a Magseed were somehow cut during surgery, the Sentimag would still detect both pieces and guide the surgeon to the tumor.
Product page: Magseed…