Initial Clinical Experience With an Inducible Magnetic Seed System for Preoperative Breast Lesion Localization

Impact of Magseed® localization on re-excision rates of non-palpable breast cancers in an Australian regional hospital

BACKGROUND

Impalpable breast cancers have traditionally been localized under hook-wire guidance. Magseed® is an innovative method of breast cancer localization that consists of a tiny paramagnetic seed designed to enable more precise tumour localization and greater scheduling flexibility by decoupling the timing of radiological insertion and surgery. The primary outcome of this study was to evaluate whether the implementation of the Magseed® localization technique in our healthcare facility led to a reduction in re-excision rates.

METHODS

A single institution retrospective evaluation was carried out for 96 women who underwent Magseed® localization (MSL) between 01 August 2020 and 30 April 2022. To allow direct comparison to the hospitals wire-guided localization (WGL) re-excision rates, data was collected from the Queensland Cancer Registry for patients who underwent WGL excision at our hospital between 01 January 2015 and 30 June 2020.

RESULTS

A total of 105 Magseeds® were inserted in 96 patients with 95% placed within 1 mm of the target lesion. All Magseeds® markers were successfully retrieved. Re-excision rates were 14% and of the re-excisions only 24% (n = 3) had residual tumour in the re-excision specimen. In the preceding 5 years when hook-wires were used as the localization technique, the re-excision rate was 38%.

CONCLUSION

Magseed® technology is a safe and effective pre-operative localization method that has the potential to reduce re-excision rates for non-palpable breast lesions.

Magnetic surgical marker navigation for excision of non-palpable ultrasound visible breast lesions: first 200 cases in a French cancer center

Wire guided localization is widely used as the standard method of pre-operative localization of breast lesions. The aim was to assess outcomes following the introduction of a novel non-wire guided, magnetic surgical marker navigation system. A prospective study between May 2022 and June 2023 established a data base of the first 200 procedures performed using the Sirius Pintuition GPS Detect magnetic marker. The primary outcome measures were the successful excision of the target lesion and retrieval of the magnetic marker. The primary lesion was excised and the magnetic marker was retrieved in all 200 procedures. In 17 procedures (8.5% of the total sample), the magnetic marker was dislodged during surgery; however, the primary lesion was still effectively excised with clear margins without the need for an additional procedure or radiologic assistance. The re-excision rate to achieve margin clearance was 9%. Insertion of the marker was classified as "easy" and "in contact with the target" by the radiologist in all cases (100%). This study has shown that surgical marker navigation reliably localizes lesions and is associated with low re-excision rates. We also perceived improvement in theater planning.

Reliability of Magseed® marking before neoadjuvant systemic therapy with subsequent contrast-enhanced mammography in patients with non-palpable breast cancer lesions after treatment: the MAGMA study

PURPOSE

To assess the reliability of excising residual breast cancer lesions after neoadjuvant systemic therapy (NAST) using a previously localized paramagnetic seed (Magseed®) and the subsequent use of contrast-enhanced spectral mammography (CESM) to evaluate response.

METHODS

Observational, prospective, multicenter study including adult women (> 18 years) with invasive breast carcinoma undergoing NAST between January 2022 and February 2023 with non-palpable tumor lesions at surgery. Radiologists marked tumors with Magseed® during biopsy before NAST, and surgeons excised tumors guided by the Sentimag® magnetometer. CESMs were performed before and after NAST to evaluate tumor response (Response Evaluation Criteria for Solid Tumors [RECIST]). We considered intraoperative, surgical, and CESM-related variables and histological response.

RESULTS

We analyzed 109 patients (median [IQR] age of 55.0 [46.0, 65.0] years). Magseed® was retrieved from breast tumors in all surgeries (100%; 95% CI 95.47-100.0%) with no displacement and was identified by radiology in 106 patients (97.24%), a median (IQR) of 176.5 (150.0, 216.3) days after marking. Most surgeries (94.49%) were conservative; they lasted a median (IQR) of 22.5 (14.75, 40.0) min (95% CI 23.59-30.11 min). Most dissected tumor margins (93.57%) were negative, and few patients (5.51%) needed reintervention. Magseed® was identified using CESM in all patients (100%); RECIST responses correlated with histopathological evaluations of dissected tumors using the Miller-Payne response grade (p < 0.0001) and residual lesion diameter (p < 0.0001). Also 69 patients (63.3%) answered a patient's satisfaction survey and 98.8% of them felt very satisfied with the entire procedure.

CONCLUSION

Long-term marking of breast cancer lesions with Magseed® is a reliable and feasible method in patients undergoing NAST and may be used with subsequent CESM.

Magseed preoperative localization in non-palpable breast lesions: Our single-center Breast Unit experience

Background

This retrospective study aimed to evaluate our single-center experience with Magseed as a pre-operative localization system in a cohort of 47 patients with non-palpable breast lesions.

Design and methods

Forty-seven patients with non-palpable breast lesions, who underwent Magseed pre-operative localization followed by breast-conserving surgery between November 2022 and June 2024 at our Breast Unit were enrolled in our study. The procedure involved percutaneous placement of the Magseed into the target lesion under ultrasound (66%) or stereotactic (34%) guidance. Data on patient demographics, lesion characteristics, Magseed localization and retrieval, surgical outcomes, and complications were collected and analyzed.

Results

Magseed localization was successful in all cases, with no marker migration or dislodgment, and all seeds were retrieved (100%). Breast-conserving surgery was successful in 97.9% of patients, with only one requiring intraoperative widening. No significant complications were reported. Histopathology revealed predominantly invasive breast cancers, with "No Special Type" being the most common subtype (42.5%).

Conclusions

The effectiveness of this technique is proven by our results, which reflect the data in the growing scientific literature on Magseed.

Assessing the Efficacy of Radioactive Iodine Seed Localisation in Targeted Axillary Dissection for Node-Positive Early Breast Cancer Patients Undergoing Neoadjuvant Systemic Therapy: A Systematic Review and Pooled Analysis

Targeted axillary dissection (TAD), employing marked lymph node biopsy (MLNB) alongside sentinel lymph node biopsy (SLNB), is increasingly recognised for its efficacy in reducing false negative rates (FNRs) in node-positive early breast cancer patients receiving neoadjuvant systemic therapy (NST). One such method, 125I radioactive seed localisation (RSL), involves implanting a seed into a biopsy-proven lymph node either pre- or post-NST. This systematic review and pooled analysis aimed to assess the performance of RSL in TAD among node-positive patients undergoing NST. Six studies, encompassing 574 TAD procedures, met the inclusion criteria. Results showed a 100% successful deployment rate, with a 97.6% successful localisation rate and a 99.8% retrieval rate. Additionally, there was a 60.0% concordance rate between SLNB and MLNB. The FNR of SLNB alone was significantly higher than it was for MLNB (18.8% versus 5.3%, respectively; p = 0.001). Pathological complete response (pCR) was observed in 44% of cases (248/564). On average, the interval from 125I seed deployment to surgery was 75.8 days (range: 0-272). These findings underscore the efficacy of RSL in TAD for node-positive patients undergoing NST, enabling precise axillary pCR identification and facilitating the safe omission of axillary lymph node dissection.

Evaluating Magnetic Seed Localization in Targeted Axillary Dissection for Node-Positive Early Breast Cancer Patients Receiving Neoadjuvant Systemic Therapy: A Comprehensive Review and Pooled Analysis

Background/Objectives: De-escalation of axillary surgery is made possible by advancements in both neoadjuvant systemic therapy (NST) and in localisation technology for breast lesions. Magseed®, developed in 2013 by Dr. Michael Douk of Cambridge, United Kingdom, is a wire-free localisation technology that facilitates the localisation and retrieval of lymph nodes for staging. Targeted axillary dissection (TAD), which entails marked lymph node biopsy (MLNB) and sentinel lymph node biopsy (SLNB), has emerged as the preferred method to assess residual disease in post-NST node-positive patients. This systematic review and pooled analysis evaluate the performance of Magseed® in TAD. Methods: The search was carried out in PubMed and Google Scholar. An assessment of localisation, retrieval rates, concordance between MLNB and SLNB, and pathological complete response (pCR) in clinically node-positive patients post NST was undertaken. Results: Nine studies spanning 494 patients and 497 procedures were identified, with a 100% successful deployment rate, a 94.2% (468/497) [95% confidence interval (CI), 93.7-94.7] localisation rate, a 98.8% (491/497) retrieval rate, and a 68.8% (247/359) [95% CI 65.6-72.0] concordance rate. pCR was observed in 47.9% (220/459) ) [95% CI 43.3-52.6] of cases. Subgroup analysis of studies reporting the pathological status of MLNB and SLNB separately revealed an FNR of 4.2% for MLNB and 17.6% for SLNB (p = 0.0013). Mean duration of implantation was 37 days (range: 0-188). Conclusions: These findings highlight magnetic seed localisation's efficacy in TAD for NST-treated node-positive patients, aiding in accurate axillary pCR identification and safe de-escalation of axillary surgery in excellent responders.

Evaluation of the SmartClip™ Nonradioactive Seed, a Novel Wireless Localization Method for the Breast: Initial Clinical Experience and Surgical Outcome

INTRODUCTION

Wire localization has been the gold standard for breast localization of non-palpable lesions for decades. This technique remains robust but has disadvantages relative to scheduling, complications of vasovagal reactions in placement, wire migration, or transection. With more modern technologies available, several implantable markers have been developed to allow uncoupling of localization by radiology and the surgical procedure on the same day. This study summarizes our experience with the EnVisio Navigation System™ utilizing SmartClip™ as the implantable tissue localization marker.

METHODS

An IRB-approved retrospective database of benign and malignant breast disease was used to perform a review of 100 consecutive patients who underwent SmartClip™ localized breast and axillary procedures in 2021. Demographic information, localization accuracy, associated surgical procedure(s) with resultant pathology findings, margin status for malignancies, and re-excision rate were collected.

RESULTS

The localized breast lesion or lymph node was excised and SmartClip™ retrieved in all cases, confirmed by intraoperative specimen radiograph. The distribution of gender and race/ethnicity among the patients who underwent surgery reflects the community population and frequency of breast cancer development among men versus women. 45.1% of the cases involved malignancy, as determined pre-operatively. Positive margins requiring re-excision constituted 18.2% of cases. In twenty-six patients, two or three SmartClips™ were placed per case for either a bracketed lesion, two separate breast lesions, and/or a breast lesion and lymph node.

CONCLUSION

Although this study is limited in patient number, it demonstrates safety of this technique and its reliability in guiding the surgeon directly to the lesion(s) of concern.

Magnetic seed versus skin tattoo localization of non-palpable breast lesions: a single institution cohort study

OBJECTIVE

The objective of this retrospective study was to investigate the accuracy and feasibility of magnetic seed compared to skin tattoo in preoperative localization of impalpable breast lesions in terms of accuracy of placement, re-excision and positive margins rates, and breast/surgical specimen volume ratio.

METHODS

We retrospectively analyzed 77 patients who underwent breast conservative surgery in our center from November 2020 to November 2021, with previous localization with skin tattoo or magnetic seed.

RESULTS

Thirty-seven magnetic seeds were placed in 36 patients (48.6%) and 40 skin tattoos were performed in the remaining cases (51.4%). The seeds were placed correctly at the two-view mammogram acquired after the insertion in 97.6% (36/37) of cases. With both methods, 100% of the index lesions were completely removed and found in the surgical specimen. The reported re-excision rate was 0% for both groups. A significant difference was observed in the volume of breast parenchyma removed between the two groups, inferior in the seed group (p = 0.046), especially in case of voluminous breasts (p = 0.003) and small lesions (dimension < 8 mm, p = 0.019).

CONCLUSIONS

Magnetic seed is a non-radioactive localization technique, feasible to place, recommended in case of non-palpable breast lesions, saving the breast parenchyma removed compared with skin tattoo, without reducing the accuracy.

CLINICAL RELEVANCE STATEMENT

Our findings contribute to the current evidence on preoperative localization techniques for non-palpable breast lesions, highlighting the efficacy of magnetic seed localization for deep and small lesions.

KEY POINTS

• Magnetic seed is a non-radioactive technique for the preoperative localization of non-palpable breast lesions studied in comparison with skin tattoo. • Magnetic seed is feasible to place in terms of post-placement migration and distance from the target lesion. • Magnetic seed is recommended in case of non-palpable breast lesions, saving the breast parenchyma removed without reducing the accuracy.

Magnetic Localization of Breast Lesions: A Large-Scale European Evaluation in a National Cancer Institute

INTRODUCTION

For decades the standard for preoperative breast lesions' localization has been wire localization. In recent years the options for nonwired localization have significantly expanded and include radioactive seeds, radar reflectors, radiofrequency identification tags and magnetic seeds. The aim of our study is to evaluate on a large scale the performance of preoperative magnetic seed localization of nonpalpable breast lesions.

MATERIAL AND METHODS

We prospectively collected data on all patients undergoing image-guided magnetic seed localization from September 2019 to December 2022. We analyzed imaging findings, histological results, and type of surgery. The primary outcome was the successful localization rate. Secondary outcomes were the successful placement rate, the ease of percutaneous positioning, the procedural complications, and the reintervention rate.

RESULTS

A total of 1123 magnetic seeds were placed in 1084 patients by 4 radiologists under ultrasound (1053) or stereotactic (70) guidance. All seeds were detectable transcutaneously in all breasts sizes and at all depths by 7 surgeons with a success rate of 100%. A total of 97.5% seeds were correctly placed into the target lesions (only 2.5% were dislocated). All radiologists have shown good compliance during the procedure, and there were no complications or safety issues. The reoperation rate was 5.1%.

CONCLUSIONS

Image-guided localization with magnetic seeds is an easy, safe, reliable, and effective method for localizing nonpalpable breast lesions. Both radiologists and surgeons agreed that the technology was intuitive to use and that it can be widely applied in preoperative localization in breast units.

The Magnetic Technique-A Novel and Promising Method to Improve Axillary Staging Localisation from a Swedish Perspective

The magnetic technique using superparamagnetic nanoparticles of iron oxide has been well established for sentinel lymph node detection. Its main advantage is in the context of logistics, with the possibility to inject several weeks before surgery and the possibility to give access to sentinel lymph node biopsy for women worldwide in places without nuclear medicine facilities. We have not yet seen the full potential of this technique, and new implications have been developed for breast tumour localisation with paramagnetic clips and axillary staging after neoadjuvant chemotherapy using paramagnetic clips inserted in lymph node metastases before chemotherapy. In this report, we have presented our experience of the magnetic technique starting in 2014, and we have highlighted our current and future research directions.

Comparison of 3 Different Systems for Non-wire Localization of Lesions in Breast Cancer Surgery

PURPOSE

Localizing breast lesions by marking tumors and their detection using probes during surgery is a common part of clinical practice. Various nonwire localization systems were intended to be compared from different perspectives.

METHODS

Various measurement experiments were performed. Localization techniques, including radioactive seed (RSLS), magnetically guided (MGLS), or radar (SLS), were compared in signal propagation in water and tissue environments, signal interference by surgical instruments, and the practical experience of surgeons. Individual experiments were thoroughly prospectively planned.

RESULTS

The RSLS signal was detectable at the largest evaluated distance, ie, 60 mm. The SLS and MGLS signal detection was shorter, up to 25 mm to 45 mm and 30 mm, respectively. The signal intensity and the maximum detection distance in water differed slightly depending on the localization marker orientation to the probe, especially for SLS and MGLS. Signal propagation in the tissue was noted to a depth of 60 mm for RSLS, 50 mm for SLS, and 20 mm for MGLS. Except for the expected signal interferences by approaching surgical instruments from any direction for MGLS, the signal interruption for RSLS and SLS was observed only by inserting instruments directly between the localization marker and probe. Moreover, the SLS signal interference by instrument touch was noted. Based on surgeons' results, individual systems did not differ significantly for most measurement condition settings.

CONCLUSION

Apparent differences noted among localization systems can help experts choose an appropriate system for a specific situation or reveal small nuances that have not yet been observed in clinical practice.

Image-Guided Localization Techniques for Metastatic Axillary Lymph Nodes in Breast Cancer; What Radiologists Should Know

Targeted axillary dissection (TAD) is an axillary staging technique after NACT that involves the removal of biopsy-proven metastatic lymph nodes in addition to sentinel lymph node biopsy (SLNB). This technique avoids the morbidity of traditional axillary lymph node dissection and has shown a lower false-negative rate than SLNB alone. Therefore, marking positive axillary lymph nodes before NACT is critical in order to locate and remove them in the subsequent surgery. Current localization methods include clip placement with intraoperative ultrasound, carbon-suspension liquids, localization wires, radioactive tracer-based localizers, magnetic seeds, radar reflectors, and radiofrequency identification devices. The aim of this paper is to illustrate the management of axillary lymph nodes based on current guidelines and explain the features of axillary lymph node markers, with relative advantages and disadvantages.

Preoperative localization of breast lesions: Comparing digital breast tomosynthesis-guided radioactive seed localization versus standard 2D stereotactic radioactive seed localization

PURPOSE

To compare single seed digital breast tomosynthesis-guided radioseed localization (DBT-L) to standard 2D stereotactic-guided radioseed localization (SGL) of the breast.

METHODS

A retrospective review of a large tertiary cancer center's database yielded 68 women who underwent preoperative DBT-L from March 2019-December 2019 and a matched cohort of 65 women who underwent SGL during the same period. The electronic medical record and radiology were reviewed for patient characteristics including breast density, exam technique, pre- and post-operative pathology, exam duration, and radiation dose to the patient. To compare margin outcomes between the groups, the chi-square test of independence was used; to compare continuous outcomes such as exam duration and total dose, the Wilcoxon rank sum test was used.

RESULTS

DBT-L and SGL localization targets included biopsy marker (62/68, 91% vs 55/65, 85%), distortion (4/68, 6% vs 2/65, <3%), focal asymmetry (1/68 and 1/65, < 2% for both), calcifications (1/68, <2% vs 4/65, 6%), and anatomic landmarks (0% vs 3/65, 5%). 72% and 71% of localizations were performed for malignant pathology in the DBT-L and SGL groups, respectively. The median duration of DBT-L was 8.3 min vs 10.3 min for SGL, representing statistically significant time savings (p = 0.003). The median total organ dose of DBT-L was 8.6 mGy vs 10.4 mGy for SGL, representing statistically significant dose savings (p = 0.018). The incidence of positive margins at surgery was not statistically different between the groups (p = 0.26).

CONCLUSION

DBT-L demonstrates both time and dose savings for the patient compared to SGL without compromising surgical outcome.

Combined use of magnetic seed and tracer in breast conserving surgery with sentinel lymph node biopsy for non-palpable breast lesions: A pilot study describing pitfalls and solutions

BACKGROUNDS

Traditionally, breast conserving surgery for non-palpable breast cancer is guided by wire or radioactive seed and radioactive tracer for sentinel lymph node biopsy (SLNB). Alternatively, a stain-less magnetic seed and superparamagnetic iron oxide tracer (SPIO) can be combined as a radioactive-free technique. The aim of this study was to define the pitfalls we encountered during implementation of this combined technique and provide solutions resulting in an instruction manual for a radio-active free procedure.

METHODS

Between January and March 2021, seventeen consecutive patients with cN0 non-palpable breast cancer were included. The magnetic seed was placed to localize the lesion and SPIO was used to identify the sentinel lymph node (SLN). A lymphoscintigraphy with Technetium-99m nano colloid was performed concomitantly in all patients as a control procedure for SPIO. Surgical outcomes are reported, including problems with placing and retrieval of the seed and SPIO and corresponding solutions.

RESULTS

Surgical excision was successful with invasive tumor-free margins in all patients. SLN detection was successful in 82% patients when compared to Technetium-99m. The most challenging issue was an overlapping magnetic signal of the seed and SPIO. Solutions are provided in detail.

CONCLUSIONS

Combined use of magnetic seed and SPIO for wide local excision and SLNB patients with non-palpable breast lesions appeared challenging due to overlapping magnetic signals. After multiple adaptations, the protocol proved to be feasible with an added advantage of eliminating the use of radioisotopes. We described the pitfalls and solutions resulting in an instruction manual for a totally radioactive-free procedure.

Results of shared learning of a new magnetic seed localisation device - A UK iBRA-NET breast cancer localisation study

INTRODUCTION

Shared learning is imperative in the assessment and safe implementation of new healthcare interventions. Magnetic seeds (Magseed®) potentially offer logistical benefit over wire localisation for non-palpable breast lesions but few data exist on outcomes comparing these techniques. A national registration study (iBRA-NET) was conducted to collate device outcomes. In order to share learning, thematic analysis was conducted to ascertain early clinical experiences of Magseed® and wire guided localisation and explore how learning events may be applied to improve clinical outcomes.

METHODS

A qualitative study of 27 oncoplastic surgeons, radiologists and physicians was conducted in January 2020 to ascertain the feasibility and challenges associated with Magseed® versus wire breast localisation surgery. Four focus groups were asked to discuss experiences, concerns and shared learning outcomes which were tabulated and analysed thematically.

RESULTS

Three key themes were identified comparing Magseed® and wire localisation of breast lesions relating to preoperative, intraoperative and postoperative learning outcomes. Percutaneous Magseed® detection, instrument interference and potential seed or wire dislodgement were the most common issues identified. Clinician experience suggested Magseed® index lesion identification was non-inferior to wire placement and improved the patient pathway in terms of scheduling and multi-site insertion.

CONCLUSIONS

Prospective shared learning suggested Magseed® offered additional non-clinical benefits over wire localisation, improving the efficiency of the patient pathway. Recommendations for improving breast localisation technique, appropriate patient selection and clinical practice through shared learning are discussed that may aid other surgeons in the adoption of this relatively new technique.

Efficacy and Accuracy of Using Magnetic Seed for Preoperative Non-Palpable Breast Lesions Localization: Our Experience with Magseed

In this retrospective study we share our single-center experience using a magnetic seed for the preoperative localization of non-palpable breast lesions. Patients who underwent a preoperative localization with Magseed® (Endomagnetics, Cambridge, UK) placement between 2020 and 2022 were enrolled. Indications to Magseed placement have been established during multidisciplinary meetings prior to surgery and all patients underwent breast-conserving surgery (BCS). 45 patients were included. Magnetic seeds have been introduced under ultrasound guidance in 40 patients (88.9%) and under stereotactic guidance in 5 patients (11.1%). We registered a highly successful placement rate (97.8%), with only one case of migration (2.2%). After BCS, all the magnetic seeds were recovered (100% retrieval rate). The re-excision rate for positive margins was 0%. Our experience, with a highly successful placement and retrieval rate and a re-excision rate equal to 0%, is consistent with the encouraging literature published on Magseed so far, suggesting this technique to be extremely effective. Moreover, our single case of seed migration supports the existing data stating that Magseed migration is rare. In conclusion, despite acknowledging Magseed limitations, we highly value the advantages linked to this technique, and we, therefore, uphold its use.

An Audit on Oncological Safety with Magseed Localised Breast Conserving Surgery

Wire-localised wide local excision (W-WLE) has been standard of care for impalpable breast lesions. Logistics and risks of wire localisation can be challenging. Magseed-localised wide local excision (M-WLE) is an alternative to W-WLE. We compare safety parameters and length of hospital stay (LOS) in patients undergoing M-WLE to W-WLE. All M-WLEs performed at single institution over an 8-month period were included and compared to historic matched cohort of W-WLEs who would have been suitable for Magseed localisation. Data including patient demographics, successful placements, re-excision rates, tumour size, and length of stay (LOS) was analysed. Two hundred thirty-eight patients were included in the study. Cancers were safely excised in all cases. A significant difference in re-excisions rates favouring M-WLE group was seen (2.9% vs 10.4%). Median waiting time to surgery was significantly shorter in M-WLE group (4 h 15 min vs 7 h 3 min). No significant difference in median LOS between the two groups was seen. M-WLE has been shown to be oncologically safe and non-inferior to W-WLE with significantly lower re-excision rate. Reduced pre-operative waiting time in the M-WLE group will have a positive effect on patient journey. Further research should focus on potential impact on day-bed utilisation and theatre efficiency.

Evaluation of Axillary Lymph Node Marking with Magseed® before and after Neoadjuvant Systemic Therapy in Breast Cancer Patients: MAGNET Study

Background. Due to the high false negative rate (FNR) associated with sentinel lymph node biopsy (SLNB) after neoadjuvant systemic therapy (NAST), the standard surgical treatment for patients with an initially positive axilla and indicated for NAST is axillary lymph node dissection (ALND). To avoid unnecessary ALND, this multicenter, prospective, observational study aimed to determine the effectiveness and ease of using magnetic seeds (Magseed®) for targeted axillary dissection (TAD) when the seeds are placed before or after NAST. Materials and Methods. We recruited 81 patients diagnosed with T1-T3 breast cancer, with clinically/radiologically positive nodal involvement (cN1, 75 patients with 1–3 nodes suspected nodes and 6 patients with up to 4 suspected nodes) prior to NAST. Positive nodes detected by fine-needle aspiration biopsy or core needle biopsy were marked with a stainless steel marker coil and after NAST with Magseed® prior to surgery (Post-NAST group), or directly with Magseed® before NAST (Pre-NAST group). The correlation between lymph nodes marked with Magseed® (MLNs) and sentinel lymph nodes (SLNs) was calculated based on pathologic assessment with the OSNA assay (Sysmex Corporation, Kobe) or conventional sectioning and staining techniques according to the standard protocols of each center. Results. All magnetic seeds were successfully identified and retrieved in just over 10 minutes of surgery, guided by the Sentimag® magnetometer system. The overall concordance rate between MLNs and SLNs was 81.5%, and the concordance between MLNs and SLNs with metastasis was 93.8%. Metastasis was detected in 54.3% of the MLNs compared with 48.1% of SLNs. In cases that presented negative MLN and negative SLN (negative TAD), the FNR was 0%. No significant differences were found between the Post-NAST and Pre-NAST groups. Conclusions. Our results validate the use of Magseed® for long-term marking of axillary lymph nodes and show that when used in combination with SLNB for TAD, a FNR of 0% can be achieved, avoiding unnecessary ALND.

Preoperative localisation of nonpalpable breast lesions using magnetic markers in a tertiary cancer centre

Background

We retrospectively evaluated safety and performance of magnetic seed localisation of nonpalpable breast lesions.

Methods

We reviewed records of patients with nonpalpable breast lesions preoperative localised by placing magnetic Magseed® marker between February 2019 and December 2020. During surgery, Sentimag® magnetic probe was used to localise the marker and guide surgery. Safety, lesion identification and excision with tumour with free margins and re-excision rate were assessed.

Results

A total of 77 Magseed® devices were placed into the breasts of 73 patients, 44 under ultrasound and 33 under stereotactic guidance (4 bilateral). All devices were retrieved as were the target lesions. Magnetic marker placement was successful in all cases without any adverse event. Intraoperative identification and excision of the localised lesion were successful in 77 of 77 of cases (100%). In three cases (all of them calcifications with the seed placed under stereotactic guidance), the seed did not reach the exact target position of the biopsy clip; thus, larger excision was needed, with localisation failure attributed to incorrect clip insertion (n = 1) or to clip dislocation (n = 2). Migration of the marker was negligible in all patients. Complete excision after the initial procedure with at least 1-mm disease-free margins was obtained in 74 out of 77 (96.1%) lesions. The re-excision rate was 3 out of 77 (4%).

Conclusions

Magnetic marker localisation for nonpalpable breast lesions was safe, reliable, and effective in terms of lesion identification, excision with tumour-free margins and re-excision rate.

Clinical Outcomes Using Magnetic Seeds as a Non-wire, Non-radioactive Alternative for Localization of Non-palpable Breast Lesions

BACKGROUND

Nonpalpable breast lesions require precise preoperative localization to facilitate negative margins with breast-conserving therapy. The traditional use of wires has several challenges including patient discomfort, wire migration, and coordination of schedules between radiology and the operating room. Radioactive seed localization overcomes some of these challenges, but radiation safety requirements have limited adoption of this technology. The authors examined their institutional experience with Magseed as an alternative technology for localization and compared outcomes with those of wire and radioactive seed localization.

METHODS

An institutional review board (IRB)-approved retrospective study was performed to evaluate patients who underwent excisional biopsy or segmental mastectomy after wire-guided localization (WGL), radioactive seed localization (RSL), or Magseed localization (ML). The clinical and pathologic factors of the three groups were assessed with a negative margin rate as the primary outcome measure.

RESULTS

Of the 1835 patients in the study, 825 underwent WGL, 449 underwent RSL, and 561 underwent ML. For the patients with either multiple lesions or a large lesion that required bracketing, multiple localization devices were placed in 31% of the WGL patients, 28% of the RSL patients, and 23% of the ML patients (p = 0.006). Negative margins were achieved in 91% of the WGL patients, 89% of the RSL patients, and 89% of the ML patients (p = 0.4).

CONCLUSION

Localization of non-palpable breast lesions using Magseed is a safe and effective alternative to WGL and RSL that overcomes radiation safety limitations and increases radiology and surgery scheduling efficiency.

Wireless localisation of breast lesions with MagSeed. A radiological perspective of 300 cases

OBJECTIVES

The purpose of this article is to review the technical and radiological aspects of MagSeed® localisation, to assess its accuracy based on post-localisation mammograms and excision specimen X-rays and to discuss the radiological experience of our institutions.

METHODS

Two-year data were collected retrospectively from three NHS boards from the West of Scotland. A total of 309 MagSeeds® were inserted under mammographic or ultrasonographic guidance in 300 women with unifocal, multifocal and/or bilateral breast lesions at the day of surgery or up to 30 days prior to it. Radiological review of post-localisation mammograms and intraoperative specimen X-rays as well as a review of the surgical outcomes were performed to assess the accuracy and efficacy of the method. Our experience relating to the technique's strengths and downsides were also noted.

RESULTS

The MagSeeds® were inserted on average 7.2 days before surgery. The localisation technique was straight forward for the radiologists. In 99% of the cases, the MagSeed® was successfully deployed and 100% of the successfully localised lesions were excised at surgery. There was no difference in the accuracy of the localisation whether this was mammographically or ultrasonographically guided. On post-localisation mammograms, the MagSeed® was radiologically accurately positioned in 97.3% of the cases. No delayed MagSeed® migration was observed. On the specimen X-rays, the lesion was centrally positioned in 45.1%, eccentric within more than 1 mm from the margin in 35.7% and in 14.8% it was at the specimen's margin. The re-excision rate was 18.3%.

CONCLUSION

The MagSeed® is an accurate and reliable localisation method in breast conserving surgery with good surgical outcomes.

ADVANCES IN KNOWLEDGE

To our knowledge, the radiological aspects of MagSeed® localisation have not been widely described in peer-reviewed journals thus far.

A multicenter prospective cohort study to evaluate feasibility of radio-frequency identification surgical guidance for nonpalpable breast lesions: design and rationale of the RFID Localizer 1 Trial

BACKGROUND

Breast cancer screening and improving imaging techniques have led to an increase in the detection rate of early, nonpalpable breast cancers. For early breast cancer, breast conserving surgery is an effective and safe treatment. Accurate intraoperative lesion localization during breast conserving surgery is essential for adequate surgical margins while sparing surrounding healthy tissue to achieve optimal cosmesis. Preoperative wire localization and radioactive seed localization are accepted standard methods to guide surgical excision of nonpalpable breast lesions. However, these techniques present significant limitations. Radiofrequency identification (RFID) technology offers a new, nonradioactive method for localizing nonpalpable breast lesions in patients undergoing breast conserving surgery. This study aims to evaluate the feasibility of RFID surgical guidance for nonpalpable breast lesions.

METHODS

This multicenter prospective cohort study was approved by the Institutional Review Board of the University Medical Center Utrecht. Written informed consent is obtained from all participants. Women with nonpalpable, histologically proven in situ or invasive breast cancer, who can undergo breast conserving surgery with RFID localization are considered eligible for participation. An RFID tag is placed under ultrasound guidance, up to 30 days preoperatively. The surgeon localizes the RFID tag with a radiofrequency reader that provides audible and visual real-time surgical guidance. The primary study outcome is the percentage of irradical excisions and reexcision rate, which will be compared to standards of the National Breast Cancer Organisation Netherlands (NABON)(≤ 15% irradical excisions of invasive carcinomas). Secondary outcomes include user acceptability/experiences, learning curve, duration and ease of the placement- and surgical procedure and adverse events.

DISCUSSION

This study evaluates the feasibility of RFID surgical guidance for nonpalpable breast lesions. Results may have implications for the future localization techniques in women with nonpalpable breast cancer undergoing breast conserving surgery.

TRIAL REGISTRATION

Netherlands National Trial Register, NL8019 , registered on September 12^th 2019.

P.KharashgahM.HaniefM.MilicaA.KhanA.BellA.SmithB.SprosonC.HollywoodC.HodgkinsK. A.RutherfordC. L.ThekkinkattilD.ShanthakumarD.RahmanE.MullapudiN. AmulyaMoradA.QuinnE.MouraF.BromleyH.ChenJ.WalterL.PrestonM.NeyazN.JafferbhoyS.OsborneR.BorgE.LumleyE.WijesingheK.RossF. A.DaviesT.ToveyS.FatayerH.WhiteheadI. J.MondaniJ.JamesK.DarraghL.KiernanT.SridharanU.AshfordS.LawsS.RobsonN.MatiasM. R. A.WilsonR. L.AliS. H.SalmanM.BuhleigahM.RathinaezhilR.HignettS.SchrireT. D.LambertW.. Wire- and magnetic-seed-guided localization of impalpable breast lesions: iBRA-NET localisation study

BACKGROUND

Wire localization is historically the most common method for guiding excision of non-palpable breast lesions, but there are limitations to the technique. Newer technologies such as magnetic seeds may allow some of these challenges to be overcome. The aim was to compare safety and effectiveness of wire and magnetic seed localization techniques.

METHODS

Women undergoing standard wire or magnetic seed localization for non-palpable lesions between August 2018 and August 2020 were recruited prospectively to this IDEAL stage 2a/2b platform cohort study. The primary outcome was effectiveness defined as accurate localization and removal of the index lesion. Secondary endpoints included safety, specimen weight and reoperation rate for positive margins.

RESULTS

Data were accrued from 2300 patients in 35 units; 2116 having unifocal, unilateral breast lesion localization. Identification of the index lesion in magnetic-seed-guided (946 patients) and wire-guided excisions (1170 patients) was 99.8 versus 99.1 per cent (P = 0.048). There was no difference in overall complication rate. For a subset of patients having a single lumpectomy only for lesions less than 50 mm (1746 patients), there was no difference in median closest margin (2 mm versus 2 mm, P = 0.342), re-excision rate (12 versus 13 per cent, P = 0.574) and specimen weight in relation to lesion size (0.15 g/mm2versus 0.138 g/mm2, P = 0.453).

CONCLUSION

Magnetic seed localization demonstrated similar safety and effectiveness to those of wire localization. This study has established a robust platform for the comparative evaluation of new localization devices.

Axillary Imaging Following a New Invasive Breast Cancer Diagnosis-A Radiologist's Dilemma

Traditionally, patients with newly diagnosed invasive breast cancer underwent axillary US to assess for suspicious axillary lymph nodes (LNs), which were then targeted for image-guided needle biopsy to determine the presence of metastasis. Over the past decade, there has been a shift towards axillary preservation. For patients with palpable lymphadenopathy, the decision to perform axillary imaging with documentation of the number and location of abnormal LNs in preparation for image-guided LN sampling is straightforward. Since LN involvement correlates with cancer size, it is reasonable to image the axilla in patients with tumors larger than 5 cm; however, for tumors smaller than 5 cm, axillary imaging is often deferred until after the tumor molecular subtype and treatment plan are established. Over the last decade, neoadjuvant chemotherapy (NACT) is increasingly used for smaller cancers with more aggressive molecular subtypes. In most cases, detecting axillary metastasis is critical when deciding whether the patient would benefit from NACT. There is increasing evidence that abnormal axillary US findings correlates with LN metastases and reliably establishes a baseline to monitor response to NACT. Depending on hormone receptor status, practices may choose to image the axilla in the setting of clinical stage T1 and T2 cancers to evaluate nodal status and help determine further steps in care. Radiologists should understand the nuances of axillary management and the scope and challenges of LN marking techniques that significantly increase the precision of limited axillary surgery.

Development of an in-line magnetometer for flow chemistry and its demonstration for magnetic nanoparticle synthesis

Despite the wide usage of magnetic nanoparticles, it remains challenging to synthesise particles with properties that exploit each application's full potential. Time consuming experimental procedures and particle analysis hinder process development, which is commonly constrained to a handful of experiments without considering particle formation kinetics, reproducibility and scalability. Flow reactors are known for their potential of large-scale production and high-throughput screening of process parameters. These advantages, however, have not been utilised for magnetic nanoparticle synthesis where particle characterisation is performed, with a few exceptions, post-synthesis. To overcome this bottleneck, we developed a highly sensitive magnetometer for flow reactors to characterise magnetic nanoparticles in solution in-line and in real-time using alternating current susceptometry. This flow magnetometer enriches the flow-chemistry toolbox by facilitating continuous quality control and high-throughput screening of magnetic nanoparticle syntheses. The sensitivity required to monitor magnetic nanoparticle syntheses at the typically low concentrations (<100 mM of Fe) was achieved by comparing the signals induced in the sample and reference cell, each of which contained near-identical pairs of induction and pick-up coils. The reference cell was filled only with air, whereas the sample cell was a flow cell allowing sample solution to pass through. Balancing the flow and reference cell impedance with a newly developed electronic circuit was pivotal for the magnetometer's sensitivity. To showcase its potential, the flow magnetometer was used to monitor two iron oxide nanoparticle syntheses with well-known particle formation kinetics, i.e., co-precipitation syntheses with sodium carbonate and sodium hydroxide as base, which have been previously studied via synchrotron X-ray diffraction. The flow magnetometer facilitated batch (on-line) and flow (in-line) synthesis monitoring, providing new insights into the particle formation kinetics as well as, effect of temperature and pH. The compact lab-scale flow device presented here, opens up new possibilities for magnetic nanoparticle synthesis and manufacturing, including 1) early stage reaction characterisation 2) process monitoring and control and 3) high-throughput screening in combination with flow reactors.

Image-guided Localization Techniques for Nonpalpable Breast Lesions: An Opportunity for Multidisciplinary Patient-centered Care

Selection of a localization method for nonpalpable breast lesions offers an opportunity for institutions to seek multidisciplinary input to promote value-based, patient-centered care. The diverse range of nonpalpable breast and axillary pathologies identified through increased utilization of screening mammography often necessitates image-guided preoperative localization for accurate lesion identification and excision. Preoperative localization techniques for breast and axillary lesions have evolved to include both wire and nonwire methods, the latter of which include radioactive seeds, radar reflectors, magnetic seeds, and radiofrequency identification tag localizers. There are no statistically significant differences in surgical outcomes when comparing wire and nonwire localization devices. Factors to consider during selection and adoption of image-guided localization systems include physician preference and ease of use, workflow efficiency, and patient satisfaction.

Multicentre evaluation of magnetic technology for localisation of non-palpable breast lesions and targeted axillary nodes

BACKGROUND

Magseed technology is a recently introduced localisation technique for impalpable breast lesions with possible advantages over traditional techniques. These include improved theatre logistics, flexibility in incision placement and improved patient experience. This multicentre study evaluates the experience of introducing Magseed technology into routine surgical practice.

METHODS

A prospective multicentre study of Magseed localised procedures was performed. Insertion data were recorded by the radiologist including lesion characteristics and Magseed insertion accuracy. The surgical team recorded time from insertion to operation, operating time and surgical satisfaction. Pathology results were reviewed for specimen weight and margins.

RESULTS

Between February 2019 and June 2020, 100 patients were enrolled. Magseed localised procedures included 18 excisional biopsies, 23 wide local excisions (WLE), 50 WLE with axillary surgery and four cases of Magseed localised breast WLE with Magseed localised axillary surgery. There were three therapeutic mammoplasties and two cases of Magseed localised targeted axillary node dissection alone. A total of 90% of Magseeds were radiologically placed within 5 mm of the target lesion/node. Time between incision and specimen removal was 17 min (range 6-40 min). All breast and axillary Magseeds were successfully identified and retrieved during surgery. The target lesion was identified in the specimen in all cases. A total of 10% of cases required further surgery for pathologically positive margins. Overall, surgeons reported that Magseed localisation was "easy" or "very easy" in 77% of cases.

CONCLUSION

Magseed is a reliable, safe and accurate surgical technique that provides logistical advantages and flexibility of surgical approach. The method was well-accepted by all users.

Magnetic Seed (Magseed) Localisation in Breast Cancer Surgery: A Multicentre Clinical Trial

INTRODUCTION

The aim of this study was to evaluate the accuracy and reliability of the Magseed magnetic marker in breast cancer surgery.

METHODS

Thirty-nine patients with 41 implanted Magseeds undergoing surgical treatment in 3 surgical oncology departments were included in the retrospective trial to study pilot use of the Magseed magnetic marker in the Czech Republic for localisation of breast tumours or pathological axillary nodes in breast cancer patients.

RESULTS

Thirty-four breast cancer and 7 pathological lymph node localisations were performed by Magseed implantation. No placement failures, or perioperative detection failures of Magseeds were observed (0/41, 0.0%), but one case of Magseed migration was present (1/41, 2.4%). All magnetic seeds were successfully retrieved (41/41, 100.0%). Negative margins were achieved in 29 of 34 (85.3%) breast tumour localisations by Magseed.

CONCLUSION

Magseed is a reliable marker for breast tumour and pathological axillary node localisation in breast cancer patients. Magseed is comparable to conventional localisation methods in terms of oncosurgical radicality and safety.

Preoperative non-palpable breast lesion localization, innovative techniques and clinical outcomes in surgical practice: A systematic review and meta-analysis

Pre-operative localization of non-palpable breast lesions with non-wired non-ionizing (NWNI) techniques may improve clinical outcomes as reoperation rate, cosmetic outcome and contribute to organizational aspects improvement in breast-conserving surgery (BCS). However only limited literature is available and clinical studies involving these forefront devices are often small and non-randomized. Furthermore, there is a lack of consensus on free margins and cosmetic outcomes definitions. The objective of the present meta-analysis was to determine the crude clinical outcomes reported for the NWNI techniques on BCS. A literature search was performed of PubMed, Embase and Scopus databases up to February 2021 in order to select all prospective or retrospective clinical trials on pre-operative breast lesion localization done with NWNI devices. All studies were assessed following the PRISMA recommendations. Continuous outcomes were described in averages corrected for sample size, while binomial outcomes were described using the weighted average proportion. Twenty-seven studies with a total of 2103 procedures were identified. The technique is consolidated, showing for both reflectors' positioning and localization nearly the 100% rate of success. The re-excision and clear margins rates were 14% (95% CI, 11-17%) and 87% (80-92%), respectively. Overall, positive margins rates were 12% (8-17%). In studies that compared NWNI and wire localization techniques, positive margin rate is lower for the first techniques (12%, 6-22% vs 17%, 12-23%) and re-excision rate is slightly higher using the latter (13%, 9-19% vs 16%, 13-18%). Pre-operative NWNI techniques are effective in the localization of non-palpable breast lesions and are promising in obtaining clear (or negative) margins minimizing the need for re-excision and improving the cosmetic outcomes. Randomized trials are needed to confirm these findings.

From the Reading Room to Operating Room: Retrospective Data and Pictorial Review After 806 SCOUT Placements

OBJECTIVE

Non-wire localization techniques are becoming more common. SCOUT surgical guidance system has been shown to increase flexibility in scheduling patients for surgery. The objective of this article is to provide institutional experiences with pictorial review after placement of 806 SCOUT devices.

MATERIALS AND METHODS

Radiology procedure reports of SCOUT device placements from January 11, 2018 to May 19, 2020 were reviewed to assess demographics of patient population, imaging method of placement, size of reflector delivery system used, placement approach, and time spent in the radiology suite or Turn Around Time (TAT). TAT was compared to that of wire placement using a Two-tailed Mann-Whitney U Test. Reports were assessed for those with absent signal at time of placement. In cases where signal was absent, migration was found, or complications noted, further case review was performed using the Electronic Medical Record to assess whether the devices were successfully retrieved.

RESULTS

There were 806 total SCOUT placements identified from radiology procedure reports in patients aged 12-92 with 64.3% (518/806) placed using ultrasound-guidance and 35.7% (288/806) by mammographic-guidance. The most common delivery device was a 7.5 cm needle. Only 0.9% (7/806) of SCOUT reflectors were >1cm from target, all of which were successfully excised. After radiology placement, signal was not heard in 1.4% (9/806) of cases and individual case review revealed that all were successfully excised. In 2019, TATs of SCOUT procedures were significantly lower than TATs from wire localizations (P = 0.00024).

CONCLUSIONS

SCOUT localization for breast surgery can provide solutions to problems encountered by patients and providers. A year after implementation, SCOUT use was found to result in shorter TATs in radiology. In addition, 100% of devices that were either migrated or inaudible at the time of radiology placement were successfully excised.

Magnetically Guided Localization Using a Guiding-Marker System® and a Handheld Magnetic Probe for Nonpalpable Breast Lesions: A Multicenter Feasibility Study in Japan

Simple Summary

In this multicenter feasibility study, non-palpable breast lesions in 89 patients were localized using a handheld cordless magnetic probe (TAKUMI) and a magnetic marker (Guiding-Marker System^®). Additionally, a dye was injected subcutaneously under ultrasound guidance to indicate the extent of the tumor. Consequently, a magnetic marker was detected in all resected specimens, and the initial surgical margin was positive only in five (6.1%) of 82 patients. Thus, the magnetic guiding localization system with ultrasound guidance is useful for the detection and excision of non-palpable breast lesions.

Abstract

Accurate pre-operative localization of nonpalpable lesions plays a pivotal role in guiding breast-conserving surgery (BCS). In this multicenter feasibility study, nonpalpable breast lesions were localized using a handheld magnetic probe (TAKUMI) and a magnetic marker (Guiding-Marker System^®). The magnetic marker was preoperatively placed within the target lesion under ultrasound or stereo-guidance. Additionally, a dye was injected subcutaneously to indicate the extent of the tumor excision. Surgeons checked for the marker within the lesion using a magnetic probe. The magnetic probe could detect the guiding marker and accurately localize the target lesion intraoperatively. All patients with breast cancer underwent wide excision with a safety margin of ≥5 mm. The presence of the guiding-marker within the resected specimen was the primary outcome and the pathological margin status and re-excision rate were the secondary outcomes. Eighty-seven patients with nonpalpable lesions who underwent BCS, from January to March of 2019 and from January to July of 2020, were recruited. The magnetic marker was detected in all resected specimens. The surgical margin was positive only in 5/82 (6.1%) patients; these patients underwent re-excision. This feasibility study demonstrated that the magnetic guiding localization system is useful for the detection and excision of nonpalpable breast lesions.

Magnetic Seed Localization (Magseed) for excision of impalpable breast lesions-The North Wales experience

The breast surgical community has faced huge challenges due to close working relationships with radiologists who are in short supply. Breast lesion localization is moving away from the traditional wire technique, which requires an on-site radiologist to support theater scheduling. In North Wales, the introduction of Magseed for impalpable breast lesion localization has facilitated theater scheduling in the absence of same day radiology presence. We audited our first 200 Magseed cases to assess the safety and efficacy of the technique, the ease of use, and patient experience. Data were entered prospectively into an excel data base relating to Magseed cases. Data collected included demographics, pre and postoperative lesion size, histology, margin positivity, and re-excision rates. Data were submitted in real time by the radiologist performing Magseed insertion to ascertain degree of difficulty. A PROMS questionnaire was designed and sent to patients undergoing Magseed vs wire localizations. Two hundred patients underwent Magseed-guided wide local excision between May 2018 and January 2020 across 2 district general hospital sites in North Wales. Histology: 69% IDC, 20% ILC, and 11% others. Mean preoperative size 12.3 mm, postoperative size 19 mm. Re-excision rate 15%. Re-excision for DCIS was significantly more likely than for invasive disease (p < 0.0001). A significant difference was also observed between radiological mean preoperative tumor size estimate and actual histological tumor size in patients undergoing margin re-excision (p = 0.000019). Wire-guided re-excision rate was 21% in the same unit. PROMs found the procedure well tolerated by patients. Surgeons and radiologists reported Magseed to be user-friendly with minimal learning curve. Magseed use for impalpable breast lesion localization is safe, user friendly, and well tolerated by patients. It produces favorable re-excision rates when compared to published figures for wire-guided excision. The presence of DCIS and preoperative radiological size underestimation was associated with margin re-excision.

Initial experience of magnetic seed localization for impalpable breast lesion excision: First 100 cases performed in a single Irish tertiary referral centre

INTRODUCTION

Wire guided localization has been widely utilized as the standard method of pre-operative localization of breast lesions. Magnetic seeds were developed to counter some of the disadvantages associated with wires. This aim of this study was to assess outcomes following the introduction of magnetic seeds at a tertiary specialist breast centre.

METHODS

A retrospective review of a prospective database of the first 100 patients who underwent magnetic seed (Magseed) guided breast surgery between November 2018 and November 2019. Data was collected from 17 wire guided cases completed during the trial phase for comparison. The primary outcome measures were successful excision of index lesion and retrieval of the magnetic seed. Secondary outcomes analyzed included time ready for theatre, post-operative complications and breast margin re-excision rate.

RESULTS

Of these 100 cases, 85 patients underwent Magseed guided wide local excision for invasive or in-situ carcinoma and 15 underwent Magseed guided diagnostic excision. The primary lesion was excised, and Magseed was retrieved in all 100 cases. 54% of patients were ready to proceed as the first scheduled theatre case of the day, compared to 0% of wire-guided cases. Amongst therapeutic Magseed guided cases, the re-excision rate for margin clearance was 9.4%.

CONCLUSION

Magseed guided breast excision is a new technology that has been implemented with relative ease in our unit. We have shown that magnetic seed guided surgery reliably localizes lesions, is associated with low re-excision rates without an increase in patient morbidity or mortality and results in improvements in theatre planning and efficiency.

Prospective Registry Trial Assessing the Use of Magnetic Seeds to Locate Clipped Nodes After Neoadjuvant Chemotherapy for Breast Cancer Patients

BACKGROUND

Targeted axillary dissection (TAD) involves locating and removing both clipped nodes and sentinel nodes for assessment of the axillary response to neoadjuvant chemotherapy (NAC) by clinically node-positive breast cancer patients. Initial reports described radioactive seeds used for localization, which makes the technique difficult to implement in some settings. This trial was performed to determine whether magnetic seeds can be used to locate clipped axillary lymph nodes for removal.

METHODS

This prospective registry trial enrolled patients who had biopsy-proven node-positive disease with a clip placed in the node and treatment with NAC. A magnetic seed was placed under ultrasound guidance in the clipped node after NAC. All the patients underwent TAD.

RESULTS

Magnetic seeds were placed in 50 patients by 17 breast radiologists. All the patients had successful seed placement at the first attempt (mean time for localization was 6.1 min; range 1-30 min). The final position of the magnetic seed was within the node (n = 44, 88%), in the cortex (n = 3, 6%), less than 3 mm from the node (n = 2, 4%), or by the clip when the node could not be adequately visualized (n = 1, 2%). The magnetic seed was retrieved at surgery from all the patients. In 49 (98%) of the 50 cases, the clip and magnetic seed were retrieved from the same node. Surgeons rated the transcutaneous and intraoperative localization as easy for 43 (86%) of the 50 cases. No device-related adverse events occurred.

CONCLUSIONS

Localization and selective removal of clipped nodes can be accomplished safely and effectively using magnetic seeds.

Novel wire-free techniques for localization of impalpable breast lesions-A review of current options

Localization methods for breast lesions including cancers have changed and advanced since their inception. Currently, the most widely used technique in the United Kingdom is the image-guided hook wire localizer developed in the 1970s. It remains as the gold standard for localization of impalpable breast tumors. Besides its advantages, there are some disadvantages associated with this technique. In recent years, novel wire-free techniques (eg, Magseed^® , SCOUT^® , and LOCalizer™) have been developed to not only localize impalpable breast lesions but also negate the disadvantages of wire localization. This article reviews the variety of techniques from their origins to the most recent advancements that are used to localize breast lesions. The future is heading toward non-wire technology and wire localization may then be reserved for special cases.

Effectiveness and Safety of Magseed-localization for Excision of Breast Lesions: A Prospective, Phase IV Trial

OBJECTIVE

A prospective, phase IV study was conducted to assess the effectiveness of Magseed to localize breast lesions requiring surgical excision.

BACKGROUND

Since FDA approval in 2016, Magseed has been increasingly used to localize non-palpable lesions due to advantages over wires or radioactive seeds. This is the first prospective, post marketing trial of Magseed.

METHODS

From 1/2017-2/2018, 107 women with lesions requiring localization were enrolled at a single institution. Primary endpoint was Magseed retrieval rate. Secondary endpoints were adverse events, accuracy of placement, surgery duration and positive margin rate. Clinicians were surveyed for ease of use using a Likert scale. Descriptive statistics and Fisher's exact test were performed to assess univariable associations with positive margins.

RESULTS

There were 124 Magseeds placed including one marker in 93 subjects, 2 markers in 11 and 3 markers in 3. The majority of lesions were masses (63%) followed by calcifications (24%). All 124 Magseeds were placed within 10mm of the target lesion and surgically retrieved with median operative time of 15min (range 4-47). No device-related adverse events occurred. Of the 98 malignant lesions, 9 had positive margins and 7 of them underwent a second surgery for additional margins. On univariable analysis, age ≤ 50 (25.0% vs 6.4%, p=0.04), lesion histology (p = 0.03), and pathologic T-stage (p = 0.04) were significantly associated with positive margins. Clinicians rated the Magseed very or fairly easy to use in most cases.

CONCLUSIONS

The Magseed system for localization of non-palpable lesions was effective and safe; all markers were successfully retrieved with margin-negative resections in 91%. This study supports use of Magseed for localization of breast lesions.

Advantages of preoperative localization and surgical resection of metastatic axillary lymph nodes using magnetic seeds after neoadjuvant chemotherapy in breast cancer

PURPOSE

To assess the safety and effectiveness of magnetic seeds in preoperative localization and surgical dissection of metastatic axillary lymph nodes (LN+) in breast cancer patients with axillary involvement, after neoadjuvant chemotherapy (NAC). In addition, to assess the impact of targeted axillary dissection (TAD) in reducing the rate of false negatives (FN) in sentinel lymph node biopsy (SLNB).

MATERIALS AND METHODS

A cross-sectional prospective cohort study was conducted from April 2017 to September 2019, including breast cancer patients with axillary lymph node involvement treated with NAC. Prior to NAC, the LN+ were marked by ultrasound-guided clip insertion. After NAC, a magnetic seed (Magseed®) was inserted in the clip-marked lymph node (MLN). During surgery, the MLN was located and removed with the aid of a magnetic detection probe (Sentimag®) and the sentinel lymph node was removed. Axillary lymph node dissection (ALND) was used to determine the rate of FN for SLNB alone and the combination of SLNB and MLN dissection, called TAD.

RESULTS

The study included 29 patients (mean age, 55; range, 30-78 years). Selective preoperative localization and surgical dissection were successful for all 30 MLNs (100%). The MLN corresponded to the SLN in 50% of cases. After ALND, there were 21.4% (3/14) FN with SLNB alone and 5.9% (1/17) with TAD.

CONCLUSIONS

Following NAC, selective surgical removal of MLN by preoperative localization using magnetic seeds is a safe and effective procedure with a success rate of 100%. Adding TAD reduces the rate of FN associated with SLNB alone.

The LOCalizer Radiofrequency Identification System: An Effective New Technology for Localizing Non-Palpable Breast Lesions for Surgery

Background. Breast screening has decreased morbidity and mortality due to detection of early, non-palpable breast cancers. One of the challenges of performing breast-conserving surgery on non-palpable breast tumours is accurate localization of the cancer. We aimed to perform a feasibility study to examine the outcomes associated with the introduction of a novel radiofrequency identification system (RFID) called LOCalizer as an alternative to traditional wire-guided localization. Methods. Data were prospectively collected on all patients undergoing breast-conserving surgery using the LOCalizer RFID system in a regional cancer centre between July 2019 and March 2020. Patients had a RFID tag placed preoperatively and underwent surgical removal of the tag with the index lesion guided by a handheld LOCalizer probe. The primary aim was successful placement and retrieval of the RFID tag. Re-excision rates, specimen size, specimen weight, cancer subtype and complication rate were all recorded. Results. Sixty-nine patients aged between 50 and 69 years had a LOCalizer tag inserted between July 2019 and March 2020. Of these, 6 (8.7%) were diagnostic and 63 (91.3%) were therapeutic. There was no migration of RFID tags, and all tags were retrieved with the index lesion. The overall re-excision of margin rate was 17.4% (12/69). All re-excision of margins was due to positive radial margins. The overall complication rate was 1.4% with one grade 1 Clavien-Dindo morbidity. Conclusion. The LOCalizer RFID is an effective and safe wire-free localization method for non-palpable breast lesions.

Patient and clinician satisfaction and clinical outcomes of Magseed compared with wire-guided localisation for impalpable breast lesions

Background

Guide-wire localisation remains the most commonly used technique for localisation of impalpable breast lesions in the UK. One alternative is magnetic seed localisation. We aimed to investigate patient and clinician satisfaction in two consecutive cohorts, describe re-excision and positive margin rates, and explore reasons for positive margins and the implications for localisation techniques.

Methods

A single-institution prospective service evaluation of two cohorts of consecutive cases of wire and then Magseed localisation was carried out. Data were collected on patient and clinician satisfaction, clinico-pathological findings, and causes of involved margins. T tests were used to compare continuous variables and Chi-squared test for satisfaction outcomes.

Results

168 consecutive cases used wire-guided localisation (WGL) and 128 subsequent cases used Magseeds. Patients reported less anxiety between localisation and surgery in the Magseed group, and clinicians reported greater ease of use of Magseeds. There were no differences in lesion size, surgical complexity, or re-excision rate between the groups. In a subset of patients receiving standard wide local excision (i.e., excluding mammoplasties), the impact on margin involvement was investigated. There was no significant difference in radiological under-sizing or accuracy of localisation. However, specimen weight and eccentricity of the lesion were statistically significantly lower in the Magseed group. Despite this, re-excision rates were not significantly different (p = 0.4).

Conclusions

This is the first large study of satisfaction with localisation and showed clinician preference for Magseed and a reduction in patient anxiety. It also demonstrated similar positive margin rates despite smaller specimen weights in the Magseed group. Magnetic seed localisation offers an acceptable clinical alternative to guide wire localisation. The impact on local service provision should also be considered.

A decade of intraoperative ultrasound guided breast conservation for margin negative resection - Radioactive, and magnetic, and Infrared Oh My…

BACKGROUND

The oncologic goal of margin-negative breast conservation requires adequate localization of tumor. Intraoperative ultrasound remains most feasible but under-utilized method to localize the tumor and assess margins.

METHODS

A prospectively maintained breast cancer database over a decade was queried for margin status in breast cancer patients undergoing breast conservation. Techniques of tumor localization, margin re-excision and closest margins were analyzed. Rate of conversion to mastectomy was determined.

RESULTS

Of the 945 breast cancer patients treated at a university-based Breast Center of Excellence between January 1, 2009 and December 31, 2018, 149(15.8%) had ductal carcinoma in situ; 712(75.3%) had invasive ductal carcinoma, and 63(6.7%) had invasive lobular carcinoma. Clinical stage distribution was: T1 = 372(39.4%); T2 = 257(27.2%); T3 = 87(9.2%). Five hundred and eighty three (61.7%) patients underwent breast conservation. The median (25th -75th centile) closest margin was 6(2.5, 10.0) mm. Thirty five (6.0%) patients underwent margin re-excision, of which 9(25%) were converted to mastectomy. Tumor localization was achieved with ultrasound in 521(89.4%) patients and with wire localization in 62(10.6%) patients. The median (25th-75th centile) closest margin with wire localization was 5.0(2.0, 8.5) mm versus 5.0 (2.0, 8.0) mm with ultrasound guidance [p = 0.6635]. The re-excision rate with wire localization was 14.5% versus 4.9% with ultrasound guidance [p = 0.0073]. The unadjusted Odds Ratio (95% CI) for margin revision in wire localized group compared with ultrasound was 3.2 (7.14, 1.42) [p = 0.0045]; multivariate adjusted OR (95%) was 4(9.09, 1.7) [p = 0.0013].

CONCLUSIONS

Ultrasound guidance for localization of breast cancer remains the most effective option for margin negative breast conservation.

Accuracy and feasibility of SentiMag technique for localization of non-palpable breast lesions

BACKGROUND

Non-palpable breast lesions are more frequent now than in the past due to the attention toward the mammary pathology and the screening diffusion; the marking of such lesions is very important for a successful surgery. The SentiMag System uses a magnetic marker that is inoculated transdermal in the breast through an 18-gauge needle.

METHODS

Between April 1st and June 30th, 2018, 16 patients with non-palpable breast lesions were selected and subjected to surgery using the SentiMag System in our Unit. They were women with a mean age of 52 years (range 30-84 years). Seven of 16 (43.7%) had a borderline preoperative histological or cytological diagnosis (C3/B3), and nine (56.3%) a diagnosis of carcinoma (C5/B5). Six (37.5%) were marked on ultrasound guidance and 10 (62.5%) on a mammography stereotaxic guide.

RESULTS

The time for the marker positioning ranged from 2 to 10 minutes. The radiological control of the surgical specimen always showed the presence of both the lesion and the marker, both centered within the specimen and intact. The pathology revealed seven benign lesions, one in-situ, and eight infiltrating carcinomas.

CONCLUSIONS

The SentiMag represents a fast and safe preoperative marking system of non-palpable breast lesions, cutting the radio exposure for personnel and patients. The marker is not displaced over time and it is rapid to place and easy to locate intraoperatively, allowing a clear dissection plane around the lesion. Thus, this reduces the amount of gland removed, improving the aesthetic result mostly in small breasts.

Node-Positive Patients Treated with Neoadjuvant Chemotherapy Can Be Spared Axillary Lymph Node Dissection with Wireless Non-Radioactive Localizers

BACKGROUND

Targeted axillary dissection (TAD) involves sentinel lymph node biopsy (SLNB) and excision of a biopsy-proven node marked by a clip. This study evaluates the feasibility of non-radioactive wireless localizers for targeted excision of clipped axillary lymph nodes.

METHODS

We identified biopsy-proven, node-positive breast cancer patients treated with neoadjuvant therapy (NAT) and TAD from 2016 to 2020, and included those with a clipped node localized using SAVI SCOUT, Magseed, or RFID Tag. Primary outcome measures were (1) successful localization (ultrasound or mammographic-guided placement < 10 mm from target), and (2) retrieval of the clipped node during TAD, documented by specimen radiography or gross visualization. Secondary outcomes included rates of completion axillary lymph node dissection (cALND) and complications.

RESULTS

Overall, 57 patients were included; 1 (1.8%) patient had no clip visible at the time of localization, and no radiographic confirmation of clip placement at the time of biopsy, and was therefore excluded. In the remaining 56 patients, localization was successful in 53 (94.6%) patients and the clipped node was retrieved during TAD in 51 (91.1%) patients. Twenty-three of 27 (85.2%) ypN0 patients were spared cALND; 3 (11.1%) patients had cALND for failed clipped node retrieval during TAD, and 1 (3.7%) for false-positive frozen section. In patients with TAD alone, the rates of axillary seroma and infection were 20.0% and 8.6%, respectively.

CONCLUSIONS

Wireless non-radioactive localizers are feasible for axillary localization after NAT, with high success rates of retrieving clipped nodes. The lack of signal decay is an advantage of these devices, allowing flexibility in timing of placement.

Preoperative Wire Localization of the Breast on the Day Before Surgery

OBJECTIVE

To assess the feasibility and accuracy of preoperative wire localization performed one day prior to surgery and the relationship between the time interval following wire placement with migration distance within the time-window examined.

METHODS

Two trials were performed with next-day mammography to assess migration. Trial 1 used a standard hooked wire (50 patients, 61 wires). Trial 2 employed a looped wire (50 patients, 59 wires). A third trial was subsequently performed (16 patients, 18 wires) using the looped wire without repeat mammograms. Complications were recorded. Comparative statistical analyses were performed between patients in Trial 1 and Trial 2.

RESULTS

In Trials 1 and 2, no wires required readjustment on the day of surgery. Mean and maximum migration were less with the looped wire (range: 0-7 mm) compared to the hooked wire (range: 0-18 mm), allowing for the elimination of next-day mammograms in Trial 3. A Mann-Whitney U test showed no significant difference between the migration distances for the first two trials (P = 0.11). A Chi-square test showed no significant difference in the direction of the migration between the two trials (P = 0.15). There was no correlation between the time interval of localization and needle migration in the first two trials (r = -0.16, P = 0.22 and -0.12, P = 0.36). Specimen radiographs demonstrated the lesion/biopsy marker clip in all cases in all three trials. No infections or bleeding occurred. Two patients developed an allergic reaction to adhesive.

CONCLUSION

Wire localization performed on the day before surgery is feasible, inexpensive, did not compromise accuracy, and successfully unlinked the radiologic and surgical procedures.

Recent Progress for the Techniques of MRI-Guided Breast Interventions and their applications on Surgical Strategy

With a high sensitivity of breast lesions, MRI can detect suspicious lesions which are occult in traditional breast examination equipment. However, the lower and variable specificity of MRI makes the MRI-guided intervention, including biopsies and localizations, necessary before surgery, especially for patients who need the treatment of breast-conserving surgery (BCS). MRI techniques and patient preparation should be first carefully considered before the intervention to avoid lengthening the procedure time and compromising targeting accuracy. Doctors and radiologists need to reconfirm the target of the lesion and be very familiar with the process approach and equipment techniques involving the computer-aided diagnosis (CAD) tools and the biopsy system and follow a correct way. The basic steps of MRI-guided biopsy and localization are nearly the same regardless of the vendor or platform, and this article systematically introduces detailed methods and techniques of MRI-guided intervention. The two interventions both face different challenging situations during procedures with solutions given in the article. Post-operative statistics show that the complications of MRI-guided intervention are infrequent and mild, and MRI-guided biopsy provides the pathological information for the subsequent surgical decisions and MRI-guided localization fully prepared for follow-up surgical biopsy. New techniques for MRI-guided intervention are also elaborated in the article, which leads to future development. In a word, MRI-guided intervention is a safe, accurate, and effective technique with a low complication rate and successful MRI-guided intervention is truly teamwork with efforts from patients to surgeons, radiologists, MRI technologists, and nurses.

Evaluation of the nonradioactive inducible magnetic seed system Magseed for preoperative localization of nonpalpable breast lesions - initial clinical experience

INTRODUCTION

Many early-stage breast cancers are not palpable and thus must be localized before surgery. Detecting these lesions is crucial before they become clinically symptomatic to avoid morbidity and mortality. Nowadays, there are several new alternative techniques to traditional needle/wire localization available. These methods allow for better surgical margins, decreased costs and operating room delays, as well as improved patient satisfaction. The purpose of this study is to evaluate the nonradioactive inducible magnetic seed system Magseed (Endomagnetics Ltd, Cambridge, UK) for preoperative localization of nonpalpable breast lesions. To our knowledge, this report documents the first clinical experience with Magseed in Poland.

MATERIAL AND METHODS

A single-institution case report of 10 women with nonpalpable breast lesions localized and excised by using the Magseed surgical guidance system between November 2017 and May 2018.

RESULTS AND CONCLUSIONS

Magseed is an easy, sensitive and effective localization method. It is beneficial for oncoplastic outcomes and for scheduling efficiency, which overcomes many limitations of other localization methods. Surgical specimen margins were evaluated in 90% of cases as negative, with no additional re-excision. Only one patient with ductal carcinoma in situ had a positive tumor margin at the axillary side.