Magnetic seeds: An alternative to wire localization for non-palpable breast lesions

Innovations in the localization techniques for non-palpable breast lesions: Make invisible visible

Non-palpable breast cancer lesions pose a challenge for surgeons to resect cancer lesions. Making 'invisible' lesions 'visible' is the main strategy. Currently, multiple preoperative localization techniques have been applied in clinical. Among them, wire-guided localization (WGL) is the most common procedure due to its convenience and low cost. However, its limitations including discomfort, wire migration and the coupling of localization and operation procedures cause troubles for surgeons and patients. The desire for localization methods improvement, accompanied by the advance of emerging science and technology, leads to the development of a series of locating approaches for breast non-palpable lesions, aiming to improve locating accuracy while reducing adverse events. These emerging methods have undergone improvements from steel wire to functional particles, from radioactivity to non-radioactive, which help doctors and patients choose a more appropriate scheme. This review outlines the principles, procedures, advantages and disadvantages of these locating methods, and highlights the latest progress and related clinical data on innovative locating approaches. Finally, we briefly discuss the current challenges and future opportunities for the clinical application of these localization approaches.

Feasibility of an indocyanine green-hyaluronic acid mixture (LuminoMark™) for targeting suspicious axillary lymph nodes in patients with breast cancer

PURPOSE

During breast cancer surgery, the use of dyes such as indigo carmine, methylene blue, or indocyanine green (ICG) for targeting axillary lymph nodes (ALNs) under ultrasound guidance can result in rapid diffusion, complicated tissue differentiation, and disruption of staining. LuminoMark™, a novel ICG-hyaluronic acid mixture, can provide real-time visualization and minimize dye spread, thereby ensuring a clear surgical field. The aim of our study was to evaluate the efficacy of LuminoMark™ for targeting ALNs in patients with breast cancer.

METHODS

A total of 13 patients with breast cancer (mean age 56.5 years; 92.3% female) and suspicious ALNs underwent targeted axillary surgery (TAS) with activated charcoal and LuminoMark™ injected into the LNs in the surgical field. The clinicopathological variables of the patients and diagnostic performance were assessed. The LNs injected with LuminoMark™ were examined for consistency with sentinel LNs (SLNs) and non-SLNs, as well as with charcoal-tattooed LNs.

RESULTS

The identification of SLNs took approximately 15.6 min from the start of skin incision, and it required 25.6 and 17.7 min, for charcoal-tattooed and LuminoMarkTM-illuminated LNs, respectively. The identification rate was 92.3% with charcoal and 100% with LuminoMark™. The concordance rate between LuminoMark™ illumination and SLNs was higher than that between charcoal tattooing and SLNs. The concordance rate between the two methods was 76.9% (n = 10). Three months after surgery, the charcoal tattoo remained visible on the skin; however, LuminoMark™ was not visible.

CONCLUSION

Although both methods demonstrated high detection rates, the rate was higher using LuminoMark™. As LuminoMark™ was administered directly into LNs, this improved the accuracy of identifying LNs.

The Effect of Wire Versus Magnetic Seed Localization on Lumpectomy Cavity Size

PURPOSE

Our purpose was to assess whether an association exists between surgical localization technique and lumpectomy cavity size on radiation therapy planning computed tomography (CT) scan.

METHODS AND MATERIALS

A single-institution retrospective review was conducted of women undergoing breast conserving surgery with wire or magnetic seed guided lumpectomy followed by adjuvant radiation therapy from 2018 to 2021. Patients of a surgeon only performing 1 localization technique or undergoing bracketed localization were excluded. The primary outcome was lumpectomy cavity size on simulation CT. Confounding due to imbalance in patient and tumor factors was addressed with overlap weights derived from a propensity score analysis and used in a weighted multivariable analysis. Secondary outcomes included positive margins, total pathologic volume, boost delivery, and boost modality.

RESULTS

Of 617 women who received lumpectomy during the study period, 387 were included in final analysis. Tumors of patients undergoing seed localization were more likely unifocal, assessable by ultrasound, and smaller. Seed use rates ranged from 27.7% to 70.7% per surgeon. There was no difference in positive margins (6.4 vs 5.4%, P = .79) or second surgeries (9.4 vs 8.1%, P = .79) between groups. Close margin rates were similar for ductal carcinoma in situ (P = .35) and invasive carcinoma (P = .97). In unadjusted bivariable analyses, wire localization was associated with larger total pathology volume (P = .004), but localization technique showed no association with CT cavity volume (P = .15). After adjusting for potentially confounding variables, multivariable analysis failed to show an association between localization technique and either CT cavity (P = .35) or total path volume (P = .08). There was no difference in indicated-boost delivery (P = .15) or electron boost (P = .14) by localization technique.

CONCLUSIONS

There was no significant difference in CT cavity size by localization technique, suggesting choice between surgical techniques does not impede radiation therapy boost delivery.

Comparison of magnetic seed and RFID methods in the localization of non-palpable breast lesions

BACKGROUND

Many methods have been developed for localizing non-palpable breast lesions. This study investigated the success rate and surgical results of the magnetic seed (Magseed) and radiofrequency identification (RFID) method, which are relatively new compared to standard wire-guided localizations.

MATERIALS AND METHODS

20 simulation (10 Magseed, 10 RFID) models were created using turkey breasts and raisins. Raisins containing magnetic seed and RFID tags were placed on the turkey breast. Sentimag® probe was used for the Magseed group, and Faxitron LOCalizer™ System device was used in the RFID group. Both methods were evaluated in terms of accuracy in detecting breast lesion localization, operation times, excised tissue weights, total resection volume, surgical margin negativity, and re-excision rates.

RESULTS

Lesion localization success in both techniques was 100%. While procedure times were statistically significantly shorter in the Magseed group, incision lengths were shorter in the RFID group (P = 0.013, P = 0.007, respectively). No statistically significant difference was found between the groups for the weight of the removed parts, total resection volume, and surgical margin distance (P > 0.05).

CONCLUSION

In this feasibility study, it was concluded that neither the RFID nor Magseed methods had a significant advantage over each other, in terms of localization detection and surgical margin negativity, and both methods could be used successfully for localization.

Breast-Conserving Surgery Guided with Magnetic Seeds vs. Wires: A Single-Institution Experience

PURPOSE

The aim of this study is to describe our initial experience using magnetic seeds (Magseed®) to guide breast-conserving surgery in non-palpable breast lesions and compare the use of magnetic seed with wires to guide breast-conserving surgery in terms of clinical and pathological characteristics.

METHODS

We performed a retrospective study including all breast-conserving surgeries for non-palpable breast lesions under 16 mm from June 2018 to May 2021. We compared breast-conserving surgeries guided with magnetic seeds (Magseed®) to those guided with wires, analyzing tumor and patient characteristics, surgical time, and pathological results of the surgical specimens.

RESULTS

Data from 225 cases were collected, including 149 cases guided by magnetic seeds and 76 cases guided by wires. The breast lesion was localized in every case. Both cohorts were similar regarding clinical and pathological characteristics. We found significant statistical differences (p < 0.02) in terms of the median volume (cm3) of the excised specimen, which was lower (29.3%) in the magnetic seed group compared with the wire group (32.5 [20.5-60.0]/46.0 [20.3-118.7]). We did not find significant differences regarding surgical time (min) or the affected or close margins.

CONCLUSION

In our experience, the use of magnetic seed (Magseed®) is a feasible option to guide breast-conserving surgery of non-palpable lesions and enabled us to resect less breast tissue.

Contribution of preoperative ultrasound-guided implantation of a magnetic seed for optimal localization and resection of vulvar angiosarcoma: A case report

INTRODUCTION

Vulvar cancer is a rare cause of malignancy among women. It is key for surgeons to achieve negative resection margins, as it greatly impacts patient's prognosis. Unfortunately, additional surgical procedures are often performed due to the regional anatomical complexity. Based on non-palpable breast tumors, where image-guided preoperative localization tools have enhanced the complete resection rates, we aimed at evaluating the feasibility of magnetic seed technique for localizing perineal lesions.

PRESENTATION OF THE CASE

We present the case of a 40-year-old female patient, who underwent iterative resections for a recurrent epithelioid angiosarcoma of the left labia major. Imaging revealed a suspicious regional involvement at 3 months of follow-up, for which another surgery was planned. We decided to target this non-palpable lesion with the Magnetic Seed technique to guide the intervention. A seed was inserted into the nodule under ultrasound guidance. Resection was then performed, with negative margins and no recurrence on last follow-up.

DISCUSSION

Surgical procedures with minimal extension are recommended in vulvar cancer, to limit the aesthetic and functional complication. Unfortunately, recurrences and residual tumors remain frequent, even higher when surgical margin safety is not achieved. Many studies have suggested the benefit of image-guided localization tools in non-palpable breast tumors. By reducing the excising volume and focusing on the lesions, relapse and complications are rarer. We considered Magnetic Seed to be the most appropriated technique for perineal lesions.

CONCLUSION

As for breast cancer, Magnetic Seed technique could be appropriate for non-palpable perineal lesions, optimizing resection margins with minimal procedures.

Comparison of Wire and Non-Wire Localisation Techniques in Breast Cancer Surgery: A Review of the Literature with Pooled Analysis

Background and Objectives: Wide local excision is a common procedure in the treatment of breast cancer. Wire-guided localisation (WGL) has been the gold standard for many years; however, several issues have been identified with this technique, and therefore, wire-free techniques have been developed. This scoping review synthesises the available literature comparing wire-guided localisation with the wire-free techniques used in breast-conserving cancer surgery. Materials and Methods: Multiple databases including Pubmed and MEDLINE were used to search articles between 1 January 2000 and 31 December 2022. Terms included "breast neoplasms", "margins of excision", and "reoperation". In total, 34/256 papers were selected for review. Comparisons were made between positive margins and re-excision rates of WGL with wire-free techniques including SAVI SCOUT, Magseed, ROLL, and RSL. Pooled p-values were calculated using chi-square testing to determine statistical significance. Results: Pooled analysis demonstrated statistically significant reductions in positive margins and re-excision rates when SAVI SCOUT, RSL, and ROLL were compared with WGL. When SAVI SCOUT was compared to WGL, there were fewer re-excisions {(8.6% vs. 18.8%; p = 0.0001) and positive margins (10.6% vs. 15.0%; p = 0.0105)}, respectively. This was also the case in the ROLL and RSL groups. When compared to WGL; lower re-excision rates and positive margins were noted {(12.6% vs. 20.8%; p = 0.0007), (17.0% vs. 22.9%; p = 0.0268)} for ROLL and for RSL, respectively {(6.8% vs. 14.9%),(12.36% vs. 21.4%) (p = 0.0001)}. Magseed localisation demonstrated lower rates of re-excision than WGL (13.44% vs. 15.42%; p = 0.0534), but the results were not statistically significant. Conclusions: SAVI SCOUT, Magseed, ROLL, and RSL techniques were reviewed. Pooled analysis indicates wire-free techniques, specifically SAVI SCOUT, ROLL, and RSL, provide statistically significant reductions in re-excision rates and positive margin rates compared to WGL. However, additional studies and systematic analysis are required to ascertain superiority between techniques.

Radiofrequency localization of nonpalpable breast cancer in a multicentre prospective cohort study: feasibility, clinical acceptability, and safety

PURPOSE

In breast conserving surgery, accurate lesion localization is essential for obtaining adequate surgical margins. Preoperative wire localization (WL) and radioactive seed localization (RSL) are widely accepted methods to guide surgical excision of nonpalpable breast lesions but are limited by logistical challenges, migration issues, and legislative complexities. Radiofrequency identification (RFID) technology may offer a viable alternative. The purpose of this study was to evaluate the feasibility, clinical acceptability, and safety of RFID surgical guidance for localization of nonpalpable breast cancer.

METHODS

In a prospective multicentre cohort study, the first 100 RFID localization procedures were included. The primary outcome was the percentage of clear resection margins and re-excision rate. Secondary outcomes included procedure details, user experience, learningcurve, and adverse events.

RESULTS

Between April 2019 and May 2021, 100 women underwent RFID guided breast conserving surgery. Clear resection margins were obtained in 89 out of 96 included patients (92.7%), re-excision was indicated in three patients (3.1%). Radiologists reported difficulties with the placement of the RFID tag, partially related to the relatively large needle-applicator (12-gauge). This led to the premature termination of the study in the hospital using RSL as regular care. The radiologist experience was improved after a manufacturer modification of the needle-applicator. Surgical localization involved a low learning curve. Adverse events (n = 33) included dislocation of the marker during insertion (8%) and hematomas (9%). The majority of adverse events (85%) occurred using the first-generation needle-applicator.

CONCLUSION

RFID technology is a potential alternative for non-radioactive and non-wire localization of nonpalpable breast lesions.

Savi-Scout Radar Localization: Transitioning From the Traditional Wire Localization to Wireless Technology for Surgical Guidance at Lumpectomies

Breast-conserving surgery or lumpectomy requires localization of the lesion prior to surgery, which is traditionally accomplished by imaging-guided wire localization. Over the last decade, alternatives to wire localization have emerged. This work reviews the literature on one such wireless technology, SaviScout radar (SSR) system, and shares our experience with using this technology for presurgical tumor localization. The SSR surgical guidance system is non-radioactive. The radiologist implants a reflector device in the breast under mammography or ultrasound guidance at any time prior to surgery. The placement of this reflector can be confirmed from the cadence of a handheld percutaneous probe of a handpiece and console system. Results from several studies show that the surgical outcomes from SSR and wire-localization are similar. SSR provides operational advantages as the scheduling for reflector placement by radiologists is decoupled from surgery, but at an increased cost compared to wire-localization.