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

SCOUT® radar reflectors for impalpable lesion localisation in the breast and axilla: our experience in the first 500 patients

AIM

This study aimed to detail our experience of using SCOUT® radar reflector for lesion localisation in the breast and axilla.

MATERIALS AND METHODS

This is a prospective cohort study describing our clinical experience with the first 500 patients who received SCOUT® to localise lesions in the breast and axilla (from 23 July 2020 to 4 April 2022). Study measures include patient demographics, lesion location, diagnostic pathways (screening or symptomatic), imaging, and surgical and pathology outcomes.

RESULTS

Of the 500 patients, most patients (n = 424; 84.8%) had a single device inserted. A total of 361 had SCOUT® inserted under ultrasound guidance, 128 under stereotactic guidance, and 11 under dual mammographic and ultrasonographic guidance. We successfully inserted SCOUT® in 33 patients for lymph node identification for potential targeted axillary dissection. The mean time between SCOUT® insertion and the planned surgical procedure was 40.6 days.

CONCLUSION

Our results suggest that SCOUT® is a promising preoperative localisation device for nonpalpable breast and axillary lesions. Its implementation has the potential to optimise the clinical workflow by eliminating the need for a separate localisation procedure using conventional localisation markers and streamlining the treatment pathway.

SCOUT® Localization Using MRI Guidance: Initial Experience

OBJECTIVE

The Food and Drug Administration approved the MRI-compatible wireless SCOUT localization system in April 2022. The purpose of this study was to evaluate feasibility of SCOUT localization under MRI guidance. We present our initial experience adopting MRI-guided SCOUT localization and compare it to MRI-guided wire localization.

METHODS

Electronic medical records and imaging were retrospectively reviewed for all patients who underwent MRI-guided SCOUT or wire localization at our institution between October 2022 and July 2023. Statistical analysis was performed using 2-sample proportion and Wilcoxon rank-sum tests.

RESULTS

There were 14 MRI-guided SCOUT and 23 MRI-guided wire localization cases during the study period. All SCOUTs were placed without complication and were considered to be in adequate proximity to the target. There was no significant difference in complication rate (P = .25) or days lapsed from MRI-detected abnormality to surgery (P = .82) between SCOUT and wire cases. SCOUT was placed at time of biopsy for 71% (10/14) of cases. 57% (8/14) of SCOUT cases were used for breast conservation surgery (BCS) compared to 100% (23/23) of wire cases (P <.01), with all 6 SCOUTs not used for BCS placed at time of biopsy.

CONCLUSION

MRI-guided SCOUT localization is feasible and offers an alternative to MRI-guided wire localization, with no SCOUT complications reported. SCOUT placement at time of biopsy obviates the need for an additional procedure, but predicting appropriateness is challenging, with 60% (6/10) of SCOUTs placed at time of MRI-guided biopsy not used for subsequent localization surgery.

SCOUT® Radar Localization at Time of Breast Biopsy

OBJECTIVE

Evaluate surgical utilization of SCOUT reflectors placed at breast biopsy.

METHODS

Consent was waived for this retrospective IRB-approved, HIPAA-compliant study. Breast biopsy examinations that reported the term "SCOUT" between January 2021 and June 2022 were identified using an institutional search engine. Cases were included if a SCOUT reflector was placed at time of breast biopsy and excluded if lesion pathology was already known. Analysis was performed at the lesion level. A multivariate-regression analysis evaluated 6 variables with potential impact on SCOUT utilization.

RESULTS

One hundred twenty-one lesions in 112 patients met inclusion criteria. Biopsy yielded 93% (113/121) malignant, 3% (4/121) elevated risk, 2% (2/121) benign-discordant, and 2% (2/121) benign-concordant results. Two cases lost to follow-up were excluded. SCOUT reflectors were utilized for lumpectomy (58%, 69/119 lesions) and excisional biopsy (6%, 7/119 lesions). SCOUTs were not utilized due to mastectomy (23%, 27/119), subsequent wire localization (2%, 2/119), and nonsurgical cases (12%, 14/119). Reflector placement utilization was 52% higher for findings less than 3.5 cm in size (P <.001), 33% higher in patients without prior treated breast cancer (P = .012), and 19% higher in patients with no suspicious ipsilateral lymph node (P = .048).

CONCLUSION

SCOUT reflector placement at time of biopsy was utilized for surgery 64% (76/119) of the time, although most (98%, 119/121) biopsies were malignant, elevated risk, or benign-discordant. Factors increasing reflector utilization include smaller lesion size, no suspicious ipsilateral lymph node, and no prior treated breast cancer.

Radar-Guided Localization and Resection for Metastatic Nodal and Soft Tissue Melanoma: A Single-Institution Retrospective Study

BACKGROUND

Radar-guided localization (RGL) offers a wire-free, nonradioactive surgical guidance method consisting of a small percutaneously-placed radar reflector and handheld probe. This study investigates the feasibility, timing, and outcomes of RGL for melanoma metastasectomy.

METHODS

We retrospectively identified patients at our cancer center who underwent RGL resection of metastatic melanoma between December 2020-June 2023. Data pertaining to patients' melanoma history, management, reflector placement and retrieval, and follow-up was extracted from patient charts and analyzed using descriptive statistics.

RESULTS

Twenty-three RGL cases were performed in patients with stage III-IV locoregional or oligometastatic disease, 10 of whom had reflectors placed prior to neoadjuvant therapy. Procedures included soft tissue nodule removals (8), index lymph node removals (13), and therapeutic lymph node dissections (2). Reflectors were located and retrieved intraoperatively in 96% of cases from a range of 2 to 282 days after placement; the last reflector was not able to be located during surgery via probe or intraoperative ultrasound. One retrieved reflector had migrated from the index lesion, thus overall success rate of reflector and associated index lesion removal was 21 of 23 (91%). All RGL-localized and retrieved index lesions that contained viable tumor (10) had microscopically negative margins. There were no complications attributable to reflector insertion and no unexpected complications of RGL surgery.

CONCLUSION

In our practice, RGL is a safe and effective surgical localization method for soft tissue and nodal melanoma metastases. The inert nature of the reflector enables implantation prior to neoadjuvant therapy with utility in index lymph node removal.