TOPLINE:
Paramagnetic seeds work just as well as standard guidewires for breast tumor localization and are easier for surgeons, radiologists, and operating room planners to use.
METHODOLOGY:
- Paramagnetic seeds have shown promise over standard guidewire localization, but the two methods of tagging breast lesions for surgical removal have never been compared head-to-head in a randomized trial.
- Paramagnetic seeds are magnetic markers smaller than a grain of rice that are injected into the lesion under ultrasound or x-ray guidance. While traditional guidewires are placed on the day of surgery, seeds can be placed up to 4 weeks ahead of time.
- In the current study, investigators at three hospitals in Sweden randomized 426 women undergoing breast-conserving surgery for early breast cancer to either paramagnetic seed (Magseed, Endomag, Cambridge, UK) or guidewire localization.
- Sentinel lymph nodes were also marked magnetically for removal by superparamagnetic iron oxide (Magtrace, Endomag, Cambridge, UK ) injected into the breast before surgery. This approach — an alternative to traditional radioisotopes and blue dye — can be done days before surgery.
TAKEAWAY:
- The investigators found no significant difference in re-excision rates (2.84% vs 2.87%), sentinel lymph node detection (98.1% vs 99.0%), or resection ratios — a metric of surgical precision — between the guidewire and seed approaches.
- The rate of failed localizations was significantly higher in the guidewire group (10.1% vs 1.9%; P < .001).
- Median operative time was significantly shorter in the seed localization group (69 min vs 75.5 min; P = .03).
- Surgery coordinators reported greater ease of planning with the seeds, radiologists reported easier preoperative localization, and surgeons reported easier detection of marked tumors during surgery.
IN PRACTICE:
Overall, the randomized trial found that “a paramagnetic marker was equivalent to the guidewire in re-excisions and excised specimen volumes, with advantages of shorter operative time, safer localization, and preferable logistics,” the authors concluded.
Another advantage of paramagnetic seeds: Surgical staff and patients were not confined to the same-day “restrictions posed by guidewire localization or radioisotope-based methods, making it an attractive alternative for numerous and diverse clinical settings,” the authors added.
SOURCE:
The work, led by Eirini Pantiora, MD, of Uppsala University, Sweden, was published in JAMA Surgery .
LIMITATIONS:
The investigators don’t yet know whether the benefits of implementing seed localization outweigh the costs.
DISCLOSURES:
The work was funded by Uppsala University, the Swedish Breast Cancer Association, and others. The senior investigator reported receiving grants from Endomag, the maker of the technology tested in the trial.
A version of this article appeared on Medscape.com.