Radioactive seed vs wire localization for nonpalpable breast lesions: A single institution review

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.

Radioactive Seed Localization for Nonpalpable Breast Lesions: Systematic Review and Meta-Analysis

BACKGROUND

This study is a systematic review with meta-analysis comparing radioactive seed localization (RSL) versus radio-guided occult lesion localization (ROLL) and wire-guided localization (WGL) for patients with impalpable breast cancer undergoing breast-conserving surgery and evaluating efficacy, safety, and logistical outcomes. The protocol is registered in PROSPERO with the number CRD42022299726.

METHODS

A search was conducted in the Embase, Lilacs, Pubmed, Scielo, Web of Science, and clinicaltrials.gov databases, in addition to a manual search in the reference list of relevant articles, for randomized clinical trials and cohort studies. Studies selected were submitted to their own data extraction forms and risk of bias analysis according to the ROB 2 and ROBINS 1 tools. A meta-analysis was performed, considering the random effect model, calculating the relative risk or the mean difference for dichotomous or continuous data, respectively. The quality of the evidence generated was analyzed by outcome according to the GRADE tool. Overall, 46 articles met the inclusion criteria and were included in this systematic review; of these, 4 studies compared RSL and ROLL with a population of 1550 women, and 43 compared RSL and WGL with a population of 19,820 women.

RESULTS

The results showed that RSL is a superior method to WGL in terms of surgical efficiency in the impalpable breast lesions' intraoperative localization, and it is at least equivalent to ROLL. Regarding security, RSL obtained results equivalent to the already established technique, the WGL. In addition to presenting promising results, RSL has been proven to be superior to WGL and ROLL technologies.

Exploiting the advantages of a wireless seed localization system that differentiates between the seeds: Breast cancer resection following neoadjuvant chemotherapy

BACKGROUND

Most wireless localization methods utilize only one means of detection for the surgeon, sufficient to localize a single small breast lesion for excision. Complex cases requiring bracketing of a larger lesion or localization of two or more close lesions can superimpose the signal from separate "seeds" with such methods. The lack of discernment between the localization "seeds" can disorient the surgeon, risking a missed lesion on excision and longer operative times. with the use of neoadjuvant chemotherapy prior to breast surgery, the necessity of localizing both a breast lesion and an axillary lymph node previously biopsied is becoming frequent.

CASE

A 44 year-old woman underwent neoadjuvant chmotherapy for a breast cancer the did not express estrogen receptor, progesterone receptor, or HER2 receptor. In establishing the extent of disease, a suspicious ipsilateral lymph node was biopsied and found to contain metastatic disease. She had an excellent response to the chemotherapy, with decreased size of the primary tumor and the previously biopsied lymph node. The patient desired breast conservation. The primary tumor and associated calcifications were bracketed using two different Smartclips™, with a third localizing the lymph node biopsied.

CONCLUSION

This report illustrates how the use of three SmartClips™, within the EnVisioTM system, allowed for separate tracking of each "seed" throughout a complex surgery in a patient following neoadjuvant chemotherapy. This resulted in successful resection of both the tumor and the tagged lymph node.

Does Localization Technique Matter for Non-palpable Breast Cancers?

BACKGROUND

There are several techniques for localization of non-palpable breast tumors, but comparisons of these techniques in terms of margin positivity and volume of tissue resected are lacking.

METHODS

Between 2011-2013 and 2016-2018, 2 randomized controlled trials involving 10 centers across the United States accrued 631 patients with stage 0-3 breast cancer, all of whom underwent breast conserving surgery. Of these, 522 had residual non-palpable tumors for which localization was required. The localization technique was left to the discretion of the individual surgeon. We compared margin positivity and volume of tissue resected between various localization techniques.

RESULTS

The majority of the patients (n = 465; 89.1%) had wire localization (WL), 50 (9.6%) had radioactive seed (RS) localization, and 7 (1.3%) had Savi Scout (SS) localization. On bivariate analysis, there was no difference in terms of margin positivity (37.8% vs. 28.0% vs. 28.6%, P = .339) nor re-excision rates (13.3% vs. 12.0% vs. 14.3%, P = .961) for the WL, RS, and SS groups, respectively. Further, the volume of tissue removed was not significantly different between the 3 groups (71.9 cm³ vs. 55.8 cm³ vs. 86.6 cm³ for the WL, RS, and SS groups, respectively, P = .340). On multivariate analysis, margin status was affected by tumor size (OR = 1.336; 95% CI: 1.148-1.554, P<.001) but not by type of localization (P = .670).

CONCLUSIONS

While there are a number of methods for tumor localization, choice of technique does not seem to influence volume of tissue resected nor margin status.