The FDA has approved Endomagnetics Inc.’s magnetic device system for guiding lymph node biopsies in breast cancer patients undergoing a mastectomy. The Sentimag Magnetic Localization System detects magnetic seeds or a magnetic drug to identify the specific lymph nodes to which cancer cells are most likely to spread from the original tumor.
A biopsy of these sentinel lymph nodes can help clinicians identify, remove and examine lymph nodes to determine whether cancer cells are present.
“Sentinel lymph node biopsies are crucial for determining whether a patient’s breast cancer has spread and helping the provider determine the most appropriate course of treatment,” said Binita Ashar, MD, director of the Division of Surgical Devices in the FDA’s Center for Devices and Radiological Health in an agency statement. “Currently, a sentinel lymph node biopsy is performed after injection of radioactive materials and/or blue dye. This magnetic system we’re approving today will offer patients undergoing mastectomy an option for their sentinel lymph biopsy procedure that does not require the injection of radioactive materials.”
The Sentimag system is comprised of a sensitive magnetic sensing probe and base unit designed to detect small amounts of Magtrace, Endomagnetics’ magnetic tracer drug which is injected into breast tissue and trapped in the lymph nodes. FDA recently approved Magtrace, a magnetic nanoparticle tracer injected into breast tissue. The agency previously approved the Sentimag device and its magnetic seed product, Magseed, according to the company.
The Magtrace particles travel to lymph nodes and become physically trapped in them. The Sentimag probe is then used to locate the sentinel lymph node or nodes (if there are more than one). The Sentimag probe is already in use around the U.S. with another of the Cambridge, England-based company’s magnetic sensing products called Magseed.
Following the injection of Magseed or Magtrace, the surgeon applies the hand-held Sentimag probe to the patient’s skin close to the tumor site containing the lymph nodes. Audio and visual alerts from the base unit indicate the sensing of the magnetic particles, enabling the surgeon to locate the sentinel lymph node or nodes (if there are more than one). The surgeon then makes a small incision and removes the node, which is checked by a pathologist for the presence of cancer cells.
A positive result may indicate the presence of cancer in the sentinel lymph node and possibly other nearby lymph nodes and other organs. This information can help a doctor determine the stage of the cancer.
These novel technologies are creating more possibilities for surgeons to perform breast conservation procedures, according to the FDA. The agency evaluated data from a trial of 147 patients to compare the Sentimag system to the control method of injecting patients with blue dye and radioactive materials together and using a gamma probe to identify the sentinel lymph node. Patients were administered both methods to compare lymph node detection rates. The lymph node detection rate for the Sentimag System was 94.3% while the control method detection rate was 93.5%. Overall, 98% of patients had the same detection rate with both the Sentimag system and the control method.
The most common adverse event reported include breast discoloration, which is reported to disappear after three months in patients who underwent mastectomy, cardiac disorder (bradycardia) and potential allergic reaction to the magnetic materials. The Sentimag system is contraindicated in any patient with hypersensitivity to iron oxide or dextran compounds It is also not recommended for patients with iron overload disease or with a metal implant in the axilla or in the chest.
Endomagnetics, Inc.’s U.S. headquarters is located in Austin, Texas.