Radar localization of breast and axillary lesions with SCOUT: a prospective single institution pilot study.

BACKGROUND: Wire-guided localization has been the mainstay of localization techniques for non-palpable breast and axillary lesions prior to excision. Evidence is still growing for relatively newer localization technologies. This study evaluated the efficacy of the wireless localization technology, SCOUT®, for both breast and axillary surgery. METHODS: Data were extracted from a prospective database (2021-2023) of consecutive patients undergoing wide local excision, excisional biopsy, targeted axillary dissection, or axillary lymph node dissection with SCOUT at a high-volume tertiary centre. Rates of successful reflector placement, intraoperative lesion localization, and reflector retrieval were evaluated. A survey of surgeon-reported ease of lesion localization and reflector retrieval was also evaluated. CLINICAL TRIAL REGISTRATION: ACTRN386751. RESULTS: One-hundred-ninety-five reflectors were deployed in 172 patients. Median interval between deployment and surgery was 3 days (range 1-20) and mean distance from reflector to lesion was 3.2 mm (standard deviation, SD 3.1). Rate of successful localization and reflector retrieval was 100% for both breast and axillary procedures. Mean operating time was 65.8 min (SD 33). None of the reflectors migrated. No reflector deployment or localization-related complications occurred. Ninety-eight percent of surgeons were satisfied with ease of localization for the first half of cases. CONCLUSION: SCOUT is an accurate and reliable method to localize and excise both breast and axillary lesions, and it may overcome some of the limitations of wire-guided localization.

Avoiding unnecessary sentinel lymph node biopsy with the use of superparamagnetic iron oxide mapping agents (Magtrace®) in breast surgery.

BACKGROUND: Superparamagnetic iron oxide (SPIO) (Magtrace®) is a non-radioactive liquid tracer that can stay in the sentinel lymph nodes for 30 days. Injection of SPIO at time of primary breast surgery where upfront sentinel lymph node biopsy (SLNB) is not immediately indicated allows for a return to theatre if pathology then identifies invasive disease. SLNB is associated with paraesthesia, pain, seroma formation and lymphoedema risk. Hence, our study aims to assess the use of SPIO to avoid upfront SLNB in breast surgery for ductal carcinoma in situ (DCIS) and prophylaxis. METHODS: Retrospective single-centre study of consecutive patients who underwent injection of SPIO tracer at time of primary breast surgery to avoid upfront SLNB at Chris O'Brien Lifehouse, Sydney, NSW, Australia over a 10-month period. RESULTS: SPIO was injected 38 times, with 34 at time of mastectomy and four cases at time of wide local excision. The indication for surgery was DCIS in 18 cases, risk reduction in 17 cases and other indications in three patients. Six cases (15.8%) required delayed SLNB (D-SLNB) due to the finding of invasive disease on post-operative histopathology. All patients who underwent D-SLNB had nodes successfully localized with SPIO. CONCLUSION: In our cohort, 84.2% of cases were able to avoid upfront SLNB, and hence avoid the associated complications of SLNB. SPIO injection was successful in localizing the SLN in all cases at time of surgery for D-SLNB. This technique was safe with few associated complications.

Cost-Effectiveness of Radar Localisation Versus Wire Localisation for Wide Local Excision of Non-palpable Breast Cancer.

BACKGROUND: Wire localisation (WL) is the "gold standard" localisation technique for wide local excision (WLE) of non-palpable breast lesions but has disadvantages that have led to the development of wireless techniques. This study compared the cost-effectiveness of radar localisation (RL) to WL. METHODS: This was a single-institution study of 110 prospective patients with early-stage breast cancer undergoing WLE using RL with the SCOUT® Surgical Guidance System (2021-2023) compared with a cohort of 110 patients using WL. Margin status, re-excision rates, and surgery delays associated with preoperative localisation were compared. Costs from a third-party payer perspective in Australian dollars (AUD$) calculated by using microcosting, break-even point, and cost-utility analyses. RESULTS: A total of 110 WLEs using RL cost a total of AUD$402,281, in addition to the device cost of AUD$77,150. The average additional cost of a surgery delay was AUD$2318. Use of RL reduced the surgery delay rate by 10% (p = 0.029), preventing 11 delays with cost savings of AUD$25,496. No differences were identified in positive margin rates (RL: 11.8% vs. WL: 17.3%, p = 0.25) or re-excision rates (RL: 14.5% vs. WL: 21.8%, p = 0.221). In total, 290 RL cases are needed to break even. The cost of WLE using RL was greater than WL by AUD$567. There was a greater clinical benefit of 1.15 quality-adjusted life-years (QALYs) and an incremental cost-utility ratio of AUD$493 per QALY favouring RL. CONCLUSIONS: Routine use of RL was a more cost-effective intervention than WL. Close to 300 RL cases are likely needed to be performed to recover costs of the medical device. CLINICAL TRIAL REGISTRATION: ACTRN12624000068561.

Detailed DNA methylation characterisation of phyllodes tumours identifies a signature of malignancy and distinguishes phyllodes from metaplastic breast carcinoma.

Phyllodes tumours (PTs) are rare fibroepithelial lesions of the breast that are classified as benign, borderline, or malignant. As little is known about the molecular underpinnings of PTs, current diagnosis relies on histological examination. However, accurate classification is often difficult, particularly for distinguishing borderline from malignant PTs. Furthermore, PTs can be misdiagnosed as other tumour types with shared histological features, such as fibroadenoma and metaplastic breast cancers. As DNA methylation is a recognised hallmark of many cancers, we hypothesised that DNA methylation could provide novel biomarkers for diagnosis and tumour stratification in PTs, whilst also allowing insight into the molecular aetiology of this otherwise understudied tumour. We generated whole-genome methylation data using the Illumina EPIC microarray in a novel PT cohort (n = 33) and curated methylation microarray data from published datasets including PTs and other potentially histopathologically similar tumours (total n = 817 samples). Analyses revealed that PTs have a unique methylome compared to normal breast tissue and to potentially histopathologically similar tumours (metaplastic breast cancer, fibroadenoma and sarcomas), with PT-specific methylation changes enriched in gene sets involved in KRAS signalling and epithelial-mesenchymal transition. Next, we identified 53 differentially methylated regions (DMRs) (false discovery rate < 0.05) that specifically delineated malignant from non-malignant PTs. The top DMR in both discovery and validation cohorts was hypermethylation at the HSD17B8 CpG island promoter. Matched PT single-cell expression data showed that HSD17B8 had minimal expression in fibroblast (putative tumour) cells. Finally, we created a methylation classifier to distinguish PTs from metaplastic breast cancer samples, where we revealed a likely misdiagnosis for two TCGA metaplastic breast cancer samples. In conclusion, DNA methylation alterations are associated with PT histopathology and hold the potential to improve our understanding of PT molecular aetiology, diagnostics, and risk stratification. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Dermatofibrosarcoma protuberans of the breast in pregnancy.

Dermatofibrosarcoma Protuberans (DFSP) is a rare, locally aggressive fibroblastic mesenchymal neoplasm, typically derived from the dermis, with the intramammary subtype being seen infrequently. We present a case of a 40-year-old woman whom was diagnosed with an intramammary DFSP during pregnancy, whom underwent successful surgical management during her second trimester. Our case demonstrates the importance of increased clinical awareness in the diagnosis and treatment of breast DFSP with careful multidisciplinary consideration.

Evolution of Indocyanine Green Fluorescence in Breast and Axilla Surgery: An Australasian Experience.

The evolution of indocyanine green (ICG) fluorescence in breast and axilla surgery from an Australasian perspective is discussed in this narrative review with a focus on breast cancer and reconstruction surgery. The authors have nearly a decade of experience with ICG in a high-volume institution, which has resulted in publications and ongoing future research evaluating its use for predicting mastectomy skin flap perfusion for reconstruction, lymphatic mapping for sentinel lymph node (SLN) biopsy, and axillary reverse mapping (ARM) for prevention of lymphoedema. In the authors' experience, routine use of ICG angiography during breast reconstruction postmastectomy was demonstrated to be cost-effective for the reduction of ischemic complications in the Australian setting. A novel tracer combination, ICG-technetium-99m offered a safe and effective substitute to the "gold standard" dual tracer for SLN biopsy, although greater costs were associated with ICG. An ongoing trial will evaluate ARM node identification using ICG fluorescence during axillary lymph node dissection and potential predictive factors of ARM node involvement. These data add to the growing literature on ICG and allow future research to build on this to improve understanding of the potential benefits of fluorescence-guided surgery in breast cancer and reconstruction surgery.

Novel Dual Tracer Indocyanine Green and Radioisotope Versus Gold Standard Sentinel Lymph Node Biopsy in Breast Cancer: The GREENORBLUE Trial.

BACKGROUND: The methods for sentinel lymph node (SLN) biopsy in breast cancer have been variable in type and number of tracers. Some units have abandoned the use of blue dye (BD) due to adverse reactions. Fluorescence-guided biopsy with indocyanine green (ICG) is a relatively novel technique. This study compared the clinical efficacy and costs between novel dual tracer ICG and radioisotope (ICG-RI) with "gold standard" BD and radioisotope (BD-RI). METHODS: Single-surgeon study of 150 prospective patients with early breast cancer undergoing SLN biopsy (2021-2022) using ICG-RI compared with a retrospective cohort of 150 consecutive previous patients using BD-RI. Number of SLNs identified, rate of failed mapping, identification of metastatic SLNs, and adverse reactions were compared between techniques. Cost-minimisation analysis performed by using Medicare item numbers and micro-costing analysis. RESULTS: Total number of SLNs identified with ICG-RI and BD-RI was 351 and 315, respectively. Mean number of SLNs identified with ICG-RI and BD-RI was 2.3 (standard deviation [SD] 1.4) and 2.1 (SD 1.1), respectively (p = 0.156). There were no cases of failed mapping with either dual technique. Metastatic SLNs were identified in 38 (25.3%) ICG-RI patients compared with 30 (20%) BD-RI patients (p = 0.641). There were no adverse reactions to ICG, whereas four cases of skin tattooing and anaphylaxis were associated with BD (p = 0.131). ICG-RI cost an additional AU$197.38 per case in addition to the initial cost for the imaging system. CLINICAL TRIAL REGISTRATION:  ACTRN12621001033831. CONCLUSIONS: Novel tracer combination, ICG-RI, provided an effective and safe alternative to "gold standard" dual tracer. The caveat was the significantly greater costs associated with ICG.

An Australian-based nomogram predicting nodal positivity for breast cancer in older patients.

INTRODUCTION: Regional nodal status is one of the most powerful prognosticators in breast cancer. The sentinel lymph node biopsy (SLNB) evaluates the first node in the axillary lymphatic basin theorised to drain the anatomical region of breast cancer. Recent literature has appropriately raised the query of the need for SLNB for breast cancer in older patients (BCOP). Though some early-stage older patients may safely have SLNB omitted, we are potentially missing the under-represented aggressive cancers. No sentinel lymph node metastases nomogram has been developed solely from BCOP data to date. This study aimed to identify older patients with breast cancer at risk for nodal involvement using a nomogram developed from their data alone. METHODS: A retrospective analysis of prospectively collected data on BCOP (aged ≥70 years) was performed using the Breast Surgery Quality Audit (BQA). Inclusion criteria were T1-2 invasive breast cancer patients that underwent a SLNB from 1st January 2001 to 31st December 2019. The primary outcome was nodal involvement. Data obtained from the dataset included: age, tumour type, tumour size in millimeters, histological grade, lymphovascular invasion, oestrogen receptor status, progesterone receptor status, HER2 status and referral source. Binary logistic regression was used to develop a nomogram. The model was internally validated by splitting the data set (80% for training and 20% for testing). A receiver operating characteristic curve was developed, with the area under the curve (AUC) and a calibration plot. RESULTS: There were 22,313 patients of which 14,856 (66.6%) were symptomatic presentations and 7457 (33.4%) were screen-detected. Invasive tumour type, tumour size, tumour grade, lymphovascular invasion, oestrogen receptors, and referral source indicated a statistically significant effect on predicting a nodal positivity event (Table 1). The AUC was 0.782 (95% CI 0.776-0.789) (Fig. 1a) and demonstrated good calibration (Fig. 1b). The negative predictive value established was 85%. CONCLUSION: We have developed an Australian sentinel lymph node metastasis nomogram for BCOP using routine histopathological data obtained pre-operatively (Fig. 2). This is the first Australian nomogram, as well as the first nomogram developed solely for BCOP - and maintains a superior AUC compared to other well-established nomograms.

Trends and variations in post-mastectomy breast reconstruction rates in Australia over 10 years.

BACKGROUND: Offering breast reconstruction (BR) at the time of mastectomy is standard of care in Australia with proven quality-of-life benefits. Previously BR rates in Australia have been low compared to similar countries. Accurate up-to-date information is needed to promote equity in access to BR and inform future planning of services. This study analysed recent trends and variations of BR uptake in Australia. METHOD: Data from the BreastSurgANZ Quality Audit (BQA) were used to identify patients who underwent mastectomy with or without reconstruction for invasive or in situ breast carcinoma from 2010 to 2019. The association between BR uptake and the variables of jurisdiction (state or territory), age, hospital type and remoteness, and remoteness of patients' home addresses were analysed. RESULTS: A total 41 880 women underwent mastectomy between 2010 to 2019. The national BR rate steadily increased from 12.8% in 2010 to 29% in 2019, with a 10-year national average of 21.3%. Statistically significant differences in BR uptake (P < 0.001) were found between states with higher rates in New South Wales and Victoria, with BR more likely in private hospitals and in younger women (P < 0.001), and less likely in remote areas (P < 0.001). CONCLUSION: The Australian BR rate has increased over the 10-year period, but significant variation still exists between states. BR is lower in older women and those living in regional and remote areas. While the steady increase in BR uptake is encouraging, barriers that exist to equitable provision of reconstructive surgical services for all women living with breast cancer still need to be corrected.

Xanthogranulomatous inflammation and spindle cell proliferation in response to silicone breast implant leakage.

This case study highlights the rare complications of silicone breast implants, as well as the diagnostic limitations of imaging. The patient initially presented with leakage of bilateral breast implants as discovered by a positron emission tomography (PET)-computerized tomography (CT) scan performed as part of a workup for small bowel Langerhans cell sarcoma metastases. The imaging results of the PET-CT scan revealed increased activity bilaterally with an enhancing, irregular, heterogeneously enhancing mass in the right breast. Given the clinical suspicion for breast implant-associated anaplastic large cell lymphoma, further investigation including surgical excision was undertaken. What initially was a concern for a serious complication of long-standing breast implants, fortuitously turned out to be a benign but exuberant xanthogranulomatous inflammatory reactive process. We hope that our report will add to the literature of this rare phenomenon and highlight it as a differential diagnosis of a mass in association with breast implants.

Trends in outcomes with adoption of indocyanine green angiography in postmastectomy reconstruction.

BACKGROUND: Indocyanine green angiography (ICGA) aims to reduce ischaemic complications by supplementing intraoperative perfusion assessment of mastectomy flaps. Learning curves for this technology have not been analysed. We evaluated changes in patient outcomes with increasing case volume after ICGA adoption in postmastectomy reconstruction. METHODS: Single-institution retrospective analysis of 320 implant-based reconstructions following mastectomy using ICGA from 2015, when it was introduced, to 2021. Cases chronologically divided into tertiles and complications amongst groups evaluated. Trends in ischaemic complications plotted using weighted moving average. CUSUM analysis determined after how many cases plateau was reached. Number of ischaemic complications prior to plateau calculated with AUC analysis. RESULTS: Ischaemic complications decreased over time (Group 1, 15.1%; Group 2, 11.2%; Group 3, 4.7%, P = 0.034). Cases of delayed reconstruction increased over time (Group 1, 6.6%; Group 2, 28%; Group 3, 22.4%; P < 0.001). Our institution reached plateau of 10% ischaemic complications after 160 cases. Mean incidence of ischaemic complications decreased from 16.9% during the first 160 cases to 3.8% after plateau was reached (P < 0.001). Eleven extra breasts (6.9%) experienced ischaemic complications, that may have been avoided if operated by surgeons after the first 160 cases. CONCLUSIONS: There was increased tendency towards a conservative approach of delaying reconstruction and decreased rates of ischaemic complications with increasing case volume after ICGA implementation. A significant number of cases were needed to reach plateau of minimal ischaemic complications. This data could encourage development of standardized protocols for this technology to shorten learning curves for improved patient outcomes.

Patterns of ischaemia and reperfusion in nipple-sparing mastectomy reconstruction with indocyanine green angiography.

BACKGROUND: Intraoperative assessment of mastectomy flaps and nipple-areola complex (NAC) with indocyanine green angiography (ICGA) for decision-making in delayed breast reconstruction after nipple-sparing mastectomy (NSM) remains to be fully elucidated. We evaluated patterns of ischaemia and reperfusion in NSM with delayed breast reconstruction and their outcomes. METHOD: Single-institution retrospective study of delayed implant-based breast reconstructions following NSM due to poor perfusion analysis on ICGA. Intraoperative ICGA perfusion values and fluorescence patterns during the delayed and subsequent reconstruction operations were analysed. RESULTS: Fifty-six (45 patients) delayed breast reconstructions following NSM were performed. The median time to reconstruction was seven days (range, 4-21 days). A total of 112 fluorescence images were reviewed. Four patterns of ischaemia were identified during initial mastectomy (Type I, diffuse ischaemia; Type II, geographic ischaemia; Type III, incisional ischaemia; Type IV, NAC only ischaemia). All, but 1 breast, had adequate reperfusion during delayed reconstruction. Obesity (BMI ≥ 30) was associated with Type I ischaemia (p < 0.001). Mean ICGA absolute and relative perfusion values during initial mastectomy were significantly lower than the perfusion values during delayed reconstruction (absolute value 6.7 versus 40.2 units, p < 0.001; relative value 10% versus 44%, p < 0.001, respectively). There were no cases of partial-thickness or full-thickness necrosis. CONCLUSIONS: Delaying breast reconstruction for NSM with ischaemia predicted by ICGA may allow blood supply to the flap and NAC to improve, reducing the risk for necrosis. Distinct patterns of ischaemia and low perfusion values with ICGA may be used in the decision to delay reconstruction.

Cost-effectiveness of indocyanine green angiography in postmastectomy breast reconstruction.

BACKGROUND: Mastectomy skin flap necrosis is a major complication of skin- or nipple-sparing mastectomy. Indocyanine green angiography (ICGA) is a novel technology that can identify flaps at risk of necrosis, but there is paucity of cost-effectiveness data particularly in the Australian context. We evaluated its cost-effectiveness in breast reconstruction surgery. METHODS: Single-institution retrospective study of 295 implant-based breast reconstructions using ICGA compared with 228 reconstructions without ICGA from 2015 to 2020. Costs were calculated using Medicare item numbers and micro-costing analysis. Break-even point analysis determined the number needed to break-even. Cost-utility analysis compared probabilities of ischaemic complications and utility estimates derived from surveys of surgeons to fit into a decision model. RESULTS: There were 295 breast reconstructions using ICGA with a total cost of AU$164,657. The average cost of treating an ischaemic complication was AU$21,375. Use of ICGA reduced the ischaemic complication rate from 14.9% to 8.8%. Ischaemic complications were prevented in 18 breasts resulting in gross cost savings of AU$384,745 and net savings of AU$220,088. Three hundred eighteen cases using ICGA are needed to break-even. The decision model demonstrated a baseline cost difference of AU$1,179, a quality-adjusted life-years (QALY) difference of 1.77, and an incremental cost-utility ratio (ICUR) of AU$656 per QALY favouring ICGA. CONCLUSIONS: Routine use of ICGA during implant-based breast reconstruction is a cost-effective intervention for the reduction of ischaemic complications in the Australian setting. ICGA use was associated with a gain of 1.77 additional years of perfect health at a cost of AU$656 more per year.

Diagnosis and management of phyllodes tumours for the surgeon: An algorithm.

A Phyllodes Tumour (PT) is an uncommon fibroepithelial lesion, with three histological grades - benign, borderline and malignant. PTs cause significant challenges in diagnosis, management and prognostication. Recent publications have clarified the definitions and prognostication of PTs. Contemporary data currently challenge international guidelines on PT management. We performed an in-depth literature review to develop a best-practice management algorithm for PTs. Diagnostic recommendations are that neither current imaging techniques, nor fine-needle biopsies, can reliably diagnose a PT. Core needle biopsy is the optimal diagnostic technique. Indeterminate or suspicious lesions are recommended to undergo an excisional biopsy due to the inherently heterogeneous nature of PTs. Management guidelines are that benign PTs should be completely excised, although an involved margin is acceptable in select situations. Borderline PTs should have a clear margin on excision due to their higher risk of recurrence, as well as the potential for a recurrence to progress to a malignant PT. In malignant PTs, a margin of 3 mm is acceptable as there is no reduction in recurrence risk if margins are >3 mm. Routine axillary surgery is not indicated in PTs, with axillary surgery only indicated in a histologically-confirmed positive axilla. Adjuvant treatment recommendations are that borderline and malignant PTs should be discussed at MDT, with radiotherapy considered in both. Chemotherapy should be discussed in malignant PT patients. In summary, we have developed an up-to-date simple algorithm to guide the surgeon's management of patients diagnosed with PTs and reduce excessive surgery.

A single-cell and spatially resolved atlas of human breast cancers.

Breast cancers are complex cellular ecosystems where heterotypic interactions play central roles in disease progression and response to therapy. However, our knowledge of their cellular composition and organization is limited. Here we present a single-cell and spatially resolved transcriptomics analysis of human breast cancers. We developed a single-cell method of intrinsic subtype classification (SCSubtype) to reveal recurrent neoplastic cell heterogeneity. Immunophenotyping using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) provides high-resolution immune profiles, including new PD-L1/PD-L2+ macrophage populations associated with clinical outcome. Mesenchymal cells displayed diverse functions and cell-surface protein expression through differentiation within three major lineages. Stromal-immune niches were spatially organized in tumors, offering insights into antitumor immune regulation. Using single-cell signatures, we deconvoluted large breast cancer cohorts to stratify them into nine clusters, termed 'ecotypes', with unique cellular compositions and clinical outcomes. This study provides a comprehensive transcriptional atlas of the cellular architecture of breast cancer.