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FDA clears Sentimag System for lymph node detection in breast cancer
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The FDA cleared the Magtrace and Sentimag Magnetic Localization System for guiding lymph node biopsies in patients with breast cancer undergoing mastectomy.
The Magtrace and Sentimag Magnetic Localization System, also called Sentimag System, (Endomagnetics) uses magnetic detection during lymph biopsy to identify sentinel lymph nodes for surgical removal.
“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,” Binita Ashar, MD, director of the division of surgical devices in the FDA’s Center for Devices and Radiological Health, said in a press release. “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 magnetic system consists of a magnetic sensing probe and base unit that detects small amounts of Magtrace, a magnetic tracer drug that is injected into breast tissue. The Magtrace particles become trapped in the lymph nodes, facilitating their magnetic detection. The Sentimag probe is applied to the patients’ skin in areas closest to the tumor site, and changes in audio and visual alerts from the base unit indicate the presence of the magnetic particles. The surgeon can then remove the lymph node for inspection of cancer cells by a pathologist.
The FDA based this approval on results from a trial of 147 patients with breast cancer. Investigators used both the magnetic system method of detection and the standard method — which consists of injecting patients with blue dye and detecting nodes through a gamma probe — to compare lymph node detection rates.
Results showed a higher lymph node detection rate for the magnetic system compared with the control method (94.3% vs. 93.5%). Overall, 98% of patients had the same lymph node detection rate with both methods of detection.
The most common adverse reaction included breast discoloration — which is reported to disappear within 3 months — as well as bradycardia and allergic reaction to the magnetic materials.
The magnetic system is contraindicated in patients with hypersensitivity to iron oxide or dextran compounds and is not recommended for those with iron overload disease or with a metal chest or axilla implant.