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

Magseed application for detecting recurrent lymph node metastasis in papillary thyroid cancer: A novel minimally invasive Approach

Papillary thyroid cancer is associated with lymph node metastasis and tumor recurrence that need repeated surgery, entailing surgical challenges with a high risk of complications such as nerve damage and bleeding. Magseed is a metal coil used to detect non-palpable lesions and is an established modality in breast cancer surgery. In this case series, we explore the feasibility of Magseed in metastasis surgery of papillary thyroid cancer. Under the guidance of ultrasonography, Magseed is injected into the target tissue and intraoperatively detected with a handheld magnetometer probe, Sentimag®. Five patients with recurrence of papillary thyroid cancer were operated on with focused Magseed-guided localization. All patients had repeated surgery and radioiodine treatments. Four of the patients had lymph node metastasis hidden in the fibrosis, and one patient had recurrent tumor tissue on the left side of the larynx. Magseed was easy to use, safe, and precise in detecting the target tissue.

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.

Magnetic seed localization is feasible for non-palpable melanoma, Merkel cell carcinoma, and soft tissue sarcoma lesions

BACKGROUND

Localization of non-palpable melanoma, Merkel cell carcinoma (MCC) and soft tissue sarcoma (STS) lesions can be difficult due to size, location, and obesity of patients or fibrosis due to previous treatments. Magnetic seed localization (MSL) is a common method to localize non-palpable breast lesions, but the feasibility of MSL for non-palpable melanoma, MCC and STS lesions has not yet been described.

METHODS

In this retrospective single center cohort study, all consecutive patients between January 2021 and October 2023 who had a resection of a non-palpable melanoma, MCC or STS lesion guided by Sirius Pintuition, a MSL technique, were included. The primary endpoint was successful lesion localization during surgery and the secondary endpoints were seed migration, negative resection margins, and complications.

RESULTS

Seventy-nine seeds were placed for 76 lesions, which were resected during 68 surgeries in 61 patients. All lesions (100 %) were localized and resected. Median time of surgery was 44 min. No seed migration was observed. A negative resection margin was achieved for 60 (78.9 %) lesions. Clavien Dindo grade ≥2 complications occurred in 7.4 %.

CONCLUSION

Magnetic seed localization with Sirius Pintuition is feasible for both non-palpable melanoma, MCC, and STS lesions.

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.

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.

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.

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.

Localization Techniques for Non-Palpable Breast Lesions: Current Status, Knowledge Gaps, and Rationale for the MELODY Study (EUBREAST-4/iBRA-NET, NCT 05559411)

BACKGROUND

Surgical excision of a non-palpable breast lesion requires a localization step. Among available techniques, wire-guided localization (WGL) is most commonly used. Other techniques (radioactive, magnetic, radar or radiofrequency-based, and intraoperative ultrasound) have been developed in the last two decades with the aim of improving outcomes and logistics.

METHODS

We performed a systematic review on localization techniques for non-palpable breast cancer.

RESULTS

For most techniques, oncological outcomes such as lesion identification and clear margin rate seem either comparable with or better than for WGL, but evidence is limited to small cohort studies for some of the devices. Intraoperative ultrasound is associated with significantly higher negative margin rates in meta-analyses of randomized clinical trials (RCTs). Radioactive techniques were studied in several RCTs and are non-inferior to WGL. Smaller studies show higher patient preference towards wire-free localization, but little is known about surgeons' and radiologists' attitudes towards these techniques.

CONCLUSIONS

Large studies with an additional focus on patient, surgeon, and radiologist preference are necessary. This review aims to present the rationale for the MELODY (NCT05559411) study and to enable standardization of outcome measures for future studies.

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.

False-negative rate in the extended prospective TATTOO trial evaluating targeted axillary dissection by carbon tattooing in clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy

PURPOSE

In clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy (NST), nodal metastases can be initially marked and then removed during surgical axillary staging. Marking methods vary significantly in terms of feasibility and cost. The purpose of the extended TATTOO trial was to report on the false-negative rate (FNR) of the low-cost method carbon tattooing.

METHODS

The international prospective single-arm TATTOO trial included clinically node-positive breast cancer patients planned for NST from November 2017 to January 2021. For the present analysis, patients who received both the targeted procedure with or without an additional sentinel lymph node (SLN) biopsy and a completion axillary lymph node dissection (ALND) were selected. Primary endpoint was the FNR.

RESULTS

Out of 172 included patients, 149 had undergone a completion ALND. The detection rate for the tattooed node was 94.6% (141 out of 149). SLN biopsy was attempted in 132 out of 149 patients with a detection rate of 91.7% (121 out of 132). SLN and tattooed node were identical in 58 out of 121 individuals (47.9%). The combined procedure, i.e. targeted axillary dissection (TAD) was successful in 147 of 149 cases (98.7%). Four out of 65 patients with a clinically node-negative status after NST had a negative TAD but metastases on ALND, corresponding to a FNR of 6.2%. All false-negative TAD procedures were performed in the first 2 years of the trial (2018-2019, p = 0.022).

CONCLUSION

Carbon tattooing is a feasible marking method for TAD with a high detection rate and an acceptably low FNR. The TATTOO trial was preregistered as prospective trial before initiation at the University of Rostock, Germany (DRKS00013169).