MarginProbe: intraoperative margin assessment during breast conserving surgery by using radiofrequency spectroscopy

Optical Emission Spectroscopy for the Real-Time Identification of Malignant Breast Tissue

Breast conserving resection with free margins is the gold standard treatment for early breast cancer recommended by guidelines worldwide. Therefore, reliable discrimination between normal and malignant tissue at the resection margins is essential. In this study, normal and abnormal tissue samples from breast cancer patients were characterized ex vivo by optical emission spectroscopy (OES) based on ionized atoms and molecules generated during electrosurgical treatment. The aim of the study was to determine spectroscopic features which are typical for healthy and neoplastic breast tissue allowing for future real-time tissue differentiation and margin assessment during breast cancer surgery. A total of 972 spectra generated by electrosurgical sparking on normal and abnormal tissue were used for support vector classifier (SVC) training. Specific spectroscopic features were selected for the classification of tissues in the included breast cancer patients. The average classification accuracy for all patients was 96.9%. Normal and abnormal breast tissue could be differentiated with a mean sensitivity of 94.8%, a specificity of 99.0%, a positive predictive value (PPV) of 99.1% and a negative predictive value (NPV) of 96.1%. For 66.6% patients all classifications reached 100%. Based on this convincing data, a future clinical application of OES-based tissue differentiation in breast cancer surgery seems to be feasible.

Reducing re-excision rates in breast conserving surgery with Margin Probe: systematic review

INTRODUCTION

Different intraoperative techniques with varying levels of evidence are available to decrease positive surgical margins during breast conserving surgery. The aim of this review is to assess the effectiveness of the MarginProbe® device as an intraoperative adjunct tool in reducing positive surgical margins, and subsequently exploring the effect on patient re-excision rates.

METHODOLOGY

A systematic review of the available medical literature was conducted from 2007 to March 2022. A literature search of Cochrane, PubMed and Embase by two independent reviewers reviwers was performed to identify eligible articles looking at the primary outcome of percentage reduction in patient re-excision rates using MarginProbe®. Secondary outcomes analysed were comparison of tissue volume removed, absolute and relative reduction in re-excision rate, cosmetic outcome, as well as MarginProbe® sensitivity and specificity.

RESULTS

A total of 12 full text articles were identified. An independent samples t-test using a total of 2680 patients found a 54.68 per cent reduction in re-excision rate with the use of MarginProbe®, which was statistically significant with a large effect size (P < 0.001; d = 1.826). Secondary outcomes showed a relatively higher sensitivity of the MarginProbe® device, at the expense of decreased specificity, and no significant impact on cosmesis and volume of breast tissue excised.

CONCLUSION

MarginProbe® is an effective intraoperative adjunct in breast-conservation surgery that reduces patient re-excision rates, with no adverse effects relating to breast cosmesis or increase in volume of excised tissue.

[Methods, applications, and future perspectives of intraoperative tissue identification]

Over the last century, there has been a steady development of new technologies for intraoperative tissue identification and differentiation. The applications are varied, with the core purpose being to identify target structures while preserving adjacent tissue and thereby follow a general paradigm of minimally invasive medicine. Particularly in oncology, a further asset of these technologies is the identification or classification of neoplastic tissue to support and improve therapy, for example, in breast cancer surgery.Many technologies under consideration make use of the different physical characteristics of treated tissues, such as induced fluorescence, optical coherence, and electrical impedance.Recent developments are focusing on moving from ex vivo to in situ and from asynchronous to real-time assistance of the clinicians, for example, by means of optical emission spectroscopy. Refinements of existing and the creation of new methods will include AI tools to make them more powerful while reducing the inter-operator variability in operative interventions. This talk addresses several aspects of the usage and suitability of these technologies for intraoperative, therapy-supporting application.

Near-Infrared II Hyperspectral Imaging Improves the Accuracy of Pathological Sampling of Multiple Cancer Types

Pathological histology is the "gold standard" for clinical diagnosis of cancer. Incomplete or excessive sampling of the formalin-fixed excised cancer specimen will result in inaccurate histologic assessment or excessive workload. Conventionally, pathologists perform specimen sampling relying on naked-eye observation, which is subjective and limited by human perception. Precise identification of cancer tissue, size, and margin is challenging, especially for lesions with inconspicuous tumors. To overcome the limits of human eye perception (visible: 400-700 nm) and improve the sampling efficiency, in this study, we propose using a second near-infrared window (NIR-II: 900-1700 nm) hyperspectral imaging (HSI) system to assist specimen sampling on the strength of the verified deep anatomical penetration and low scattering characteristics of the NIR-II optical window. We used selected NIR-II HSI narrow bands to synthesize color images for human eye observation and also applied a machine learning-based algorithm on the complete NIR-II HSI data for automatic tissue classification to assist pathologists in specimen sampling. A total of 92 tumor samples were collected, including 7 types. Sixty-two (62/92) samples were used as the validation set. Five experienced pathologists marked the contour of the cancer tissue on conventional color images by using different methods, and compared it with the "gold standard," showing that NIR-II HSI-assisted methods had significant improvements in determining cancer tissue compared with conventional methods (conventional color image with or without X-ray). The proposed system can be easily integrated into the current workflow, with high imaging efficiency and no ionizing radiation. It may also find applications in intraoperative detection of residual lesions and identification of different tissues.

High wavenumber Raman spectroscopy for intraoperative assessment of breast tumour margins

Optimal oncological results and patient outcomes are achieved in surgery for early breast cancer with breast conserving surgery (BCS) where this is appropriate. A limitation of BCS occurs when cancer is present at, or close, to the resection margin - termed a 'positive' margin - and re-excision is recommended to reduce recurrence rate. This is occurs in 17% of BCS in the UK and there is therefore a critical need for a way to assess margin status intraoperatively to ensure complete excision with adequate margins at the first operation. This study presents the potential of high wavenumber (HWN) Raman spectroscopy to address this. Freshly excised specimens from thirty patients undergoing surgery for breast cancer were measured using a surface Raman probe, and a multivariate classification model to predict normal versus tumour was developed from the data. This model achieved 77.1% sensitivity and 90.8% specificity following leave one patient out cross validation, with the defining features being differences in water content and lipid versus protein content. This demonstrates the feasibility of HWN Raman spectroscopy to facilitate future intraoperative margin assessment at specific locations. Clinical utility of the approach will require further research.

In situ Raman spectroscopy and machine learning unveil biomolecular alterations in invasive breast cancer

SIGNIFICANCE

As many as 60% of patients with early stage breast cancer undergo breast-conserving surgery. Of those, 20% to 35% need a second surgery because of incomplete resection of the lesions. A technology allowing in situ detection of cancer could reduce re-excision procedure rates and improve patient survival.

AIM

Raman spectroscopy was used to measure the spectral fingerprint of normal breast and cancer tissue ex-vivo. The aim was to build a machine learning model and to identify the biomolecular bands that allow one to detect invasive breast cancer.

APPROACH

The system was used to interrogate specimens from 20 patients undergoing lumpectomy, mastectomy, or breast reduction surgery. This resulted in 238 ex-vivo measurements spatially registered with standard histology classifying tissue as cancer, normal, or fat. A technique based on support vector machines led to the development of predictive models, and their performance was quantified using a receiver-operating-characteristic analysis.

RESULTS

Raman spectroscopy combined with machine learning detected normal breast from ductal or lobular invasive cancer with a sensitivity of 93% and a specificity of 95%. This was achieved using a model based on only two spectral bands, including the peaks associated with C-C stretching of proteins around 940    cm - 1 and the symmetric ring breathing at 1004    cm - 1 associated with phenylalanine.

CONCLUSIONS

Detection of cancer on the margins of surgically resected breast specimen is feasible with Raman spectroscopy.

Routine four-quadrant cavity shaving at the time of wide local excision for breast cancer reduces re-excision rate

INTRODUCTION

Breast conservation therapy (BCT) has been shown to have comparable long-term survival outcomes when compared with mastectomy. Clearance of excision margin is one of the mainstays of the surgical treatment, which if not achieved at the first operation of BCT results in the need for subsequent surgery.

METHODS

This study evaluated the impact of routinely taken cavity shavings on re-excision rates. This retrospective two-centre study describes the use of routine four-quadrant cavity shaving in 449 patients with consecutively treated with wide local excision for invasive cancer or ductal carcinoma in situ.

RESULTS

The overall incomplete excision rate was 10.6%. Routine cavity shaving prevented the need for re-excision in 84 patients (18.7%) and identified the need for further re-excision in 33 patients (7.3%). Median time from surgery to radiotherapy was 50 days (range 13-209) for non-re-excised patients versus 78 days (range 47-260) for re-excised patients (p<0.001). Median time to chemotherapy (n=75) was 44 days (range 14-106) for non-re-excised patients versus 56 days (range 35-116) for re-excised patients (p=0.017).

CONCLUSIONS

This study demonstrates that routine cavity shaving decreases re-excision rate in patients treated with wide local excision and prevents delays to adjuvant treatment due to incomplete excision.

Investigating the feasibility of a hand-held photoacoustic imaging probe for margin assessment during breast conserving surgery

Approximately 19 % of breast cancer patients undergoing breast conserving surgery (BCS) must return for a secondary surgery due to incomplete tumour removal. Our previous work demonstrated that the lower lipid content, characteristic of tumour tissue, was observed as regions of hypo-intense photoacoustic (PA) contrast. The goal of this work was to evaluate feasibility of a low-frequency, hand-held PA imaging probe for surgical margin assessment based on lipid content differences. Here, we describe (i) the design of a prototype hand-held PA imaging probe, (ii) the effect of limited-bandwidth on image contrast, (iii) accuracy towards hypo-intense contrast detection, (iv) the limited-view characteristics of the single sensor design, and (iv) early imaging results of an ex-vivo breast cancer specimen. The probe incorporates a single polyvinylidene fluoride acoustic sensor, a 1-to-4 optical fibre bundle and a polycarbonate axicon lens for light delivery. Imaging results on phantoms designed to mimic positive margins demonstrated the ability to detect gaps in optical absorption as small as 1 mm in width. Compared to images from a near full-view PAI system, the hand-held PAI probe had higher signal to noise ratio but suffered from negativity image artifacts. Lumpectomy specimen imaging showed that strong signals can be obtained from the fatty tissue. Taken together, the results show this imaging approach with a hand-held probe has potential for detection of residual breast cancer tissue during BCS; however, more work is needed to reduce the size of the probe to fit within the surgical cavity.

Complex Permittivity of Ex-Vivo Human, Bovine and Porcine Brain Tissues in the Microwave Frequency Range

Accurate knowledge about the dielectric properties of biological tissues in the microwave frequency range may lead to advancement of biomedical applications based on microwave technology. However, the published data are very scarce, especially for human brain tissues. The aim of this work was to measure and report the complex permittivity of brain white matter, grey matter and cerebellum. Complex permittivity was measured on human, bovine and porcine brain tissues in the microwave frequency range from 0.5 to 18 GHz using an open-ended coaxial probe. The results present a valuable addition to the available data on the brain tissue complex permittivity. Some noticeable variations between the results lead to several conclusions. Complex permittivity variation within the same tissue type of the individual species was comparable to interspecies variation. The difference was prominent between human brains obtained from autopsies, while bovine brains obtained from healthy animals showed very similar complex permittivity. We hypothesize that the difference might have been caused by the basic pathologies of the patients, where the associated therapies could have affected the brain water content. We also examined the effect of excised tissue degradation on its complex permittivity over the course of three days, and the results suggest the gradual dehydration of the samples.

Radiofrequency spectroscopy with intraoperative pathological assessment for breast carcinoma: synergistic or redundant?

BACKGROUND

Published MarginProbe (Dune Medical Devices Ltd., Israel) data reports ≥50% reduction in positive lumpectomy margins. We sought to determine whether adjunctive use of MarginProbe would provide value over intraoperative pathologic assessment alone.

METHODS

This is a retrospective chart review of 86 consecutive lumpectomies with MarginProbe from December 2018 to November 2019. Margins were considered positive using 'no ink on tumor' guideline for invasive cancer, and 2 mm or greater for ductal carcinoma in-situ. Significance was measured using Fisher's exact test.

RESULTS

Seventy-six patients yielded 86 lumpectomies for inclusion. Mean age was 69.8 and mean tumor size was 1.09 cm. Sixty-eight invasive cancers were assessed using adjunct MarginProbe and gross assessment, while 18 ductal carcinoma in-situ cases utilized MarginProbe only. Among all cases, gross assessment alone reduced positive margins(29.2% relative reduction, p = 0.28). Utilizing both modalities, positive margins decreased from 27.9% to 9.3% (66.7% relative reduction, p < 0.01) representing a 46.9% relative reduction versus gross assessment alone. After gross assessment and MarginProbe evaluation, additional excised volume averaged 2.9 cc.

CONCLUSIONS

Synergistic use of MarginProbe and gross assessment reduces positive margins during breast conserving surgery. Surgeons can weigh its cost against it benefit with the succinct analysis we provide.

Human study on cancer diagnostic probe (CDP) for real-time excising of breast positive cavity side margins based on tracing hypoxia glycolysis; checking diagnostic accuracy in non-neoadjuvant cases

BACKGROUND

Cancer diagnostic probe (CDP) had been developed to detect involved breast cavity side margins in real-time (Miripour et al. Bioeng Transl Med. e10236.). Here, we presented the results of the in vivo human model CDP studies on non-neoadjuvant cases.

METHODS

This study is a prospective, blind comparison to a gold standard, and the medical group recruited patients. CDP and frozen data were achieved before the permanent pathology experiment. The main outcome of the study is surgical margin status. From November 2018 to April 2020, 202 patients were registered, and 188 were assigned for the study. Breast-conserving surgery at any age or gender, re-surgery due to re-currency, or involved margins are acceptable. Patients must be non-neoadjuvant. The reliability of CDP scoring had been evaluated by the pathology of the scored IMs. Then, three models of the study were designed to compare CDP with the frozen sections. Receiver operating characteristic (ROC) curves and AUC were measured based on the permanent postoperative pathology gold standard.

RESULTS

A matched clinical diagnostic categorization between the pathological results of the tested IMs and response peaks of CDP on 113 cases, was reported (sensitivity = 97%, specificity = 89.3%, accuracy = 92%, positive predictive value (PPV) = 84.2%, and negative predictive value (NPV) = 98%). Study A showed the independent ability of CDP for IM scoring (sensitivity = 80%, specificity = 90%, accuracy = 90%, PPV = 22.2%, and NPV = 99.2%). Study B showed the complementary role of CDP to cover the missed lesions of frozen sections (sensitivity = 93.8%, specificity = 91%, accuracy = 91%, PPV = 55.6%, and NPV = 99.2%). Study C showed the ability of CDP in helping the pathologist to reduce his/her frozen miss judgment (specificity = 92%, accuracy = 93%, PPV = 42.1%, and NPV = 100%). Results were reported based on the post-surgical permanent pathology gold standard.

CONCLUSION

CDP scoring ability in intra-operative margin detection was verified on non-neoadjuvant breast cancer patients. Non-invasive real-time diagnosis of IMs with pathological values may make CDP a distinct tool with handheld equipment to increase the prognosis of breast cancer patients.

Assessment of photoacoustic tomography contrast for breast tissue imaging using 3D correlative virtual histology

Current breast tumor margin detection methods are destructive, time-consuming, and result in significant reoperative rates. Dual-modality photoacoustic tomography (PAT) and ultrasound has the potential to enhance breast margin characterization by providing clinically relevant compositional information with high sensitivity and tissue penetration. However, quantitative methods that rigorously compare volumetric PAT and ultrasound images with gold-standard histology are lacking, thus limiting clinical validation and translation. Here, we present a quantitative multimodality workflow that uses inverted Selective Plane Illumination Microscopy (iSPIM) to facilitate image co-registration between volumetric PAT-ultrasound datasets with histology in human invasive ductal carcinoma breast tissue samples. Our ultrasound-PAT system consisted of a tunable Nd:YAG laser coupled with a 40 MHz central frequency ultrasound transducer. A linear stepper motor was used to acquire volumetric PAT and ultrasound breast biopsy datasets using 1100 nm light to identify hemoglobin-rich regions and 1210 nm light to identify lipid-rich regions. Our iSPIM system used 488 nm and 647 nm laser excitation combined with Eosin and DRAQ5, a cell-permeant nucleic acid binding dye, to produce high-resolution volumetric datasets comparable to histology. Image thresholding was applied to PAT and iSPIM images to extract, quantify, and topologically visualize breast biopsy lipid, stroma, hemoglobin, and nuclei distribution. Our lipid-weighted PAT and iSPIM images suggest that low lipid regions strongly correlate with malignant breast tissue. Hemoglobin-weighted PAT images, however, correlated poorly with cancerous regions determined by histology and interpreted by a board-certified pathologist. Nuclei-weighted iSPIM images revealed similar cellular content in cancerous and non-cancerous tissues, suggesting malignant cell migration from the breast ducts to the surrounding tissues. We demonstrate the utility of our nondestructive, volumetric, region-based quantitative method for comprehensive validation of 3D tomographic imaging methods suitable for bedside tumor margin detection.

Electrochemical tracing of hypoxia glycolysis by carbon nanotube sensors, a new hallmark for intraoperative detection of suspicious margins to breast neoplasia

For most people, the first step in treatment is to take out the tumor (surgery), so precise and fast diagnosis of any sign of high-risk and neoplastic cells, especially in surgical cavity margins, is significant. The frozen pathology method is the conventional standard of intraoperative diagnosis, but the low number of slides prepared from non-fixed tissues prevents us from achieving a perfect diagnosis. Although many improvements in intraoperative margin detection were achieved, still real-time detection of neoplastic lesions is crucial to improving diagnostic quality. Functionalized carbon nanotubes grown on the electrode needles lively and selectively determine the H2O2 released from cancer/atypical cells through reverse Warburg effect and hypoxia assisted glycolysis pathways in a quantitative electrochemical manner. The study was carried out on cell lines, 57 in vivo mice models with breast cancer, and 258 fresh in vitro samples of breast cancer tumors. A real-time electrotechnical system, named cancer diagnostic probe (CDP) (US Patent Pub. No.: US 2018/02991 A1, US 2021/0007638 A1, and US 2021/0022650 A1 [publications], and US 10,786,188 B1 [granted]), has been developed to find pre-neoplastic/neoplastic cells in vivo in a quantitative electrochemical manner by tracing hypoxia glycolysis byproducts. Matched pathological evaluations with response peaks of CDP were found based on the presence of neoplasia (from atypia to invasive carcinoma) in live breast tissues. The ability of CDP to find neoplastic lesions in mice models in vivo and fresh breast tumors in vitro was verified with sensitivity and specificity of 95% and 97%, respectively. The system may help a surgeon assistant system for usage in the operating room after passing many trials and standard examinations in the future.

Accuracy of cancer diagnostic probe for intra-surgical checking of cavity side margins in neoadjuvant breast cancer cases: A human model study

BACKGROUND

Background Recently, a real-time system, named cancer diagnostic probe (CDP), has been developed to diagnose the presence of pre-neoplastic/neoplastic cells in breast cavity side margins. Detecting mechanism is real-time determination of the ROS/H₂ O₂ released from cancer or atypical cells, through reverse Warburg effect and hypoxia glycolysis pathways.

AIMS

Here, we designed a human model study based on real-time checking of 387 internal margins (IM) from 39 neoadjuvant breast cancer cases by CDP. MATERIALS & METHODS: Each lesion was checked by entered needle sensor and electrical scores were recorded. The permanent pathology result of each tested lesion was our gold standard to evaluate CDP scoring. CDP results were compared with permanent pathology of tumour side margins (as a conventional margin evaluation procedure).

RESULTS

Results showed that the sensitivity of CDP in scoring the cavity side margins of those cases is 91%. A total of 18 involved IM which had been detected by CDP were declared as free margins in pathology section of tumour side samples. Just five involved IM were missed by CDP.

DISCUSSIONS

Such sensitivity revealed that metabolism based (here: hypoxia glycolysis) tracing of cancer cells show distinct electrochemical responses between clear and involved cavity side margin evaluation.

CONCLUSION

This human study showed the promising role of CDP to achieve clear margins after BCS of neoadjuvant cases.

Use of high-resolution full-field optical coherence tomography and dynamic cell imaging for rapid intraoperative diagnosis during breast cancer surgery

BACKGROUND

Although traditional intraoperative assessments (ie, frozen sections) may lower reoperation rates in patients with breast cancer, time/tissue limitations and accuracy concerns have discouraged their routine clinical use. Full-field optical coherence tomography (FFOCT) and dynamic cell imaging (DCI) are novel optical imaging techniques offering rapid histologic approximations that are unfettered by requisite handling steps. This study was conducted to determine the feasibility and diagnostic utility of FFOCT and DCI in examining breast and lymph node specimens during breast cancer surgery.

METHODS

FFOCT and DCI were applied to normal and cancerous breast tissue, benign breast lesions, and resected axillary lymph nodes. The tissues were then subjected to conventional processing and staining (hematoxylin-eosin) for purposes of comparison.

RESULTS

A total of 314 specimens, including 173 breast biopsies (malignant, 132; benign/normal, 41) and 141 resected lymph nodes (tumor-positive, 48; tumor-negative, 93), were obtained from 158 patients during breast surgery for prospective imaging evaluations. In breast cancer diagnosis, the minimum sensitivities (FFOCT, 85.6%; DCI, 88.6%) and specificities of optical imaging (FFOCT, 85.4%; DCI, 95.1%) were high, although they diverged somewhat in nodal assessments (FFOCT sensitivity, 66.7%; FFOCT specificity, 79.6%; DCI sensitivity, 83.3%; DCI specificity, 98.9%).

CONCLUSIONS

These timely and tissue-sparing optical imaging techniques proved highly accurate in diagnosing breast cancer and nodal metastasis. They compare favorably with routine histologic sections and demonstrate their promise in this setting.

Differentiation of breast tissue types for surgical margin assessment using machine learning and polarization-sensitive optical coherence tomography

We report an automated differentiation model for classifying malignant tumor, fibro-adipose, and stroma in human breast tissues based on polarization-sensitive optical coherence tomography (PS-OCT). A total of 720 PS-OCT images from 72 sites of 41 patients with H&E histology-confirmed diagnoses as the gold standard were employed in this study. The differentiation model is trained by the features extracted from both one standard OCT-based metric (i.e., intensity) and four PS-OCT-based metrics (i.e., phase difference between two channels (PD), phase retardation (PR), local phase retardation (LPR), and degree of polarization uniformity (DOPU)). Further optimized by forward searching and validated by leave-one-site-out-cross-validation (LOSOCV) method, the best feature subset was acquired with the highest overall accuracy of 93.5% for the model. Furthermore, to show the superiority of our differentiation model based on PS-OCT images over standard OCT images, the best model trained by intensity-only features (usually obtained by standard OCT systems) was also obtained with an overall accuracy of 82.9%, demonstrating the significance of the polarization information in breast tissue differentiation. The high performance of our differentiation model suggests the potential of using PS-OCT for intraoperative human breast tissue differentiation during the surgical resection of breast cancer.

Optical palpation for tumor margin assessment in breast-conserving surgery

Intraoperative margin assessment is needed to reduce the re-excision rate of breast-conserving surgery. One possibility is optical palpation, a tactile imaging technique that maps stress (force applied across the tissue surface) as an indicator of tissue stiffness. Images (optical palpograms) are generated by compressing a transparent silicone layer on the tissue and measuring the layer deformation using optical coherence tomography (OCT). This paper reports, for the first time, the diagnostic accuracy of optical palpation in identifying tumor within 1 mm of the excised specimen boundary using an automated classifier. Optical palpograms from 154 regions of interest (ROIs) from 71 excised tumor specimens were obtained. An automated classifier was constructed to predict the ROI margin status by first choosing a circle diameter, then searching for a location within the ROI where the circle was ≥ 75% filled with high stress (indicating a positive margin). A range of circle diameters and stress thresholds, as well as the impact of filtering out non-dense tissue regions, were tested. Sensitivity and specificity were calculated by comparing the automated classifier results with the true margin status, determined from co-registered histology. 83.3% sensitivity and 86.2% specificity were achieved, compared to 69.0% sensitivity and 79.0% specificity obtained with OCT alone on the same dataset using human readers. Representative optical palpograms show that positive margins containing a range of cancer types tend to exhibit higher stress compared to negative margins. These results demonstrate the potential of optical palpation for margin assessment.

Margin Assessment and Re-excision Rates for Patients Who Have Neoadjuvant Chemotherapy and Breast-Conserving Surgery

BACKGROUND

Neoadjuvant chemotherapy (NAC) has enabled more patients to be eligible for breast-conservation surgery (BCS). Achieving negative lumpectomy margins, however, is challenging due to changes in tissue composition and potentially scattered residual carcinoma in the tumor bed. Data regarding BCS after NAC have shown variable re-excision rates. MarginProbe (Dilon Technologies, Newport News, VA, USA) has been shown to identify positive resection margins intraoperatively and to reduce the number of re-excisions in primary BCS, but has not been studied in NAC+BCS cases. This study aimed to investigate the clinicopathologic characteristics, margin status, and re-excision rates for NAC+BCS patients with and without the use of MarginProbe.

METHODS

The Institutional Breast Cancer Database was queried for patients who received NAC and had BCS from 2010 to 2019. The variables of interest were demographics, tumor characteristics, pathologic complete response (pCR), MarginProbe use, and re-excision rates.

RESULTS

The study population consisted of 214 patients who had NAC, 61 (28.5 %) of whom had NAC+BCS. The median age of the patients was 53.5 years. A pCR was achieved for 19 of the patients (31.1 %). Of the remaining 42 patients, 9 (21 %) had close or positive margins that required re-excision. Re-excision was associated with a larger residual tumor size (p = 0.025) and estrogen receptor (ER)-positive disease before NAC (p = 0.041). MarginProbe use was associated with a lower re-excision rate for the patients who had NAC+BCS (6 % vs. 31 %, respectively).

CONCLUSION

The patients with a larger residual tumor burden and ER-positive disease had a greater risk for inadequate margins at surgery. MarginProbe use was associated with a lower re-excision rate. Techniques to reduce the need for re-excision will support the use of BCS after NAC.

Review of Laser Raman Spectroscopy for Surgical Breast Cancer Detection: Stochastic Backpropagation Neural Networks

Laser Raman spectroscopy (LRS) is a highly specific biomolecular technique which has been shown to have the ability to distinguish malignant and normal breast tissue. This paper discusses significant advancements in the use of LRS in surgical breast cancer diagnosis, with an emphasis on statistical and machine learning strategies employed for precise, transparent and real-time analysis of Raman spectra. When combined with a variety of "machine learning" techniques LRS has been increasingly employed in oncogenic diagnostics. This paper proposes that the majority of these algorithms fail to provide the two most critical pieces of information required by the practicing surgeon: a probability that the classification of a tissue is correct, and, more importantly, the expected error in that probability. Stochastic backpropagation artificial neural networks inherently provide both pieces of information for each and every tissue site examined by LRS. If the networks are trained using both human experts and an unsupervised classification algorithm as gold standards, rapid progress can be made understanding what additional contextual data is needed to improve network classification performance. Our patients expect us to not simply have an opinion about their tumor, but to know how certain we are that we are correct. Stochastic networks can provide that information.

AND-gate contrast agents for enhanced fluorescence-guided surgery

The surgical resection of tumours requires the precise location and definition of the margins between lesions and normal tissue. However, this is made difficult by irregular margin borders. Although molecularly targeted optical contrast agents can be used to define tumour margins during surgery in real time, the selectivity of the contrast agents is often limited by the target being expressed in both healthy and tumour tissues. Here, we show that AND-gate optical imaging probes requiring the processing of two substrates by multiple tumour-specific enzymes produce a fluorescent signal with significantly improved specificity and sensitivity to tumour tissue. We evaluated the performance of the probes in mouse models of mammary tumours and of metastatic lung cancer, and during fluorescence-guided robotic surgery. Imaging probes relying on multivariate activation to selectively target complex patterns of enzymatic activity should be useful in disease detection, treatment and monitoring.

A Single institution's randomized double-armed prospective study of lumpectomy margins with adjunctive use of the MarginProbe in nonpalpable breast cancers

Breast conservation surgery (BCS) aims to excise all cancerous tissue while minimizing the amount of healthy breast tissue removed. Up to 30% of patients undergoing BCS require a second operation for re-excision to obtain negative margins. Previous studies reported a lower re-excision rate with intraoperative use of the MarginProbe device (Dune Medical Devices). This device utilizes radiofrequency spectroscopy to detect differences between cancerous and normal tissue. From July 2009 to January 2010, our institution enrolled 46 patients electing for BCS in a prospective double-arm randomized controlled trial and had a significantly lower re-excision rate than that reported in the multicenter trial. Intraoperatively, after performing conventional lumpectomy with excision of any additional shavings deemed necessary based on palpation and visual inspection alone, patients were then randomized. In the device arm, the surgeon used the MarginProbe to interrogate the lumpectomy specimen, taking additional shavings from the cavity surfaces corresponding to the parts of the specimen read as positive by the device. In the control arm, only standard intraoperative assessments were performed. All specimens were evaluated by pathologists who were blinded to the study arm. In this population, 72% had invasive ductal carcinoma (IDC), 20% had ductal carcinoma in situ (DCIS), and 8% had invasive lobular carcinoma (ILC). Average age was 64 years old. The average size of the specimen was 5.6 cm, the average volume was 37.8 cm³ , and the average weight was 32.7 g. The mean size of DCIS was 1.4 cm. For invasive specimens, 32 were T1 and 7 were T2. Prior to randomization, 43 patients were thought to have positive or close margins and therefore underwent additional shavings. Twenty-three patients were randomized to the device arm and 23 to the control arm. In the device arm, 14 (60%) patients had IDC, 7 (30%) had DCIS, and 2 (8%) had ILC, vs the control arm where 19 (82%) patients had IDC, 2 (8%) had DCIS, and 2 (8%) had ILC. Eight (35%) patients in the control group vs 1 (4%) in the device group underwent re-excision for margin involvement (P < .05). The use of the MarginProbe device at our institution significantly improved the ability of our surgeons to obtain clear margins during initial BCS. Our results show a lower re-excision rate (4%) than those published in the multicenter trial (19.8%). We postulate that in the face of more patients having DCIS in our device group (30%), our surgeons responded by taking thicker shavings when the MarginProbe device reported margin involvement during the initial lumpectomy, resulting in greater success achieving clear final margins on the shaved tissue and a significantly lower re-excision rate than previously reported with the MarginProbe device.

Three-dimensional mapping of the attenuation coefficient in optical coherence tomography to enhance breast tissue microarchitecture contrast

Effective intraoperative tumor margin assessment is needed to reduce re-excision rates in breast-conserving surgery (BCS). Mapping the attenuation coefficient in optical coherence tomography (OCT) throughout a sample to create an image (attenuation imaging) is one promising approach. For the first time, three-dimensional OCT attenuation imaging of human breast tissue microarchitecture using a wide-field (up to ~45 × 45 × 3.5 mm) imaging system is demonstrated. Representative results from three mastectomy and one BCS specimen (from 31 specimens) are presented with co-registered postoperative histology. Attenuation imaging is shown to provide substantially improved contrast over OCT, delineating nuanced features within tumors (including necrosis and variations in tumor cell density and growth patterns) and benign features (such as sclerosing adenosis). Additionally, quantitative micro-elastography (QME) images presented alongside OCT and attenuation images show that these techniques provide complementary contrast, suggesting that multimodal imaging could increase tissue identification accuracy and potentially improve tumor margin assessment.

A review of clinical photoacoustic imaging: Current and future trends

Photoacoustic imaging (or optoacoustic imaging) is an upcoming biomedical imaging modality availing the benefits of optical resolution and acoustic depth of penetration. With its capacity to offer structural, functional, molecular and kinetic information making use of either endogenous contrast agents like hemoglobin, lipid, melanin and water or a variety of exogenous contrast agents or both, PAI has demonstrated promising potential in a wide range of preclinical and clinical applications. This review provides an overview of the rapidly expanding clinical applications of photoacoustic imaging including breast imaging, dermatologic imaging, vascular imaging, carotid artery imaging, musculoskeletal imaging, gastrointestinal imaging and adipose tissue imaging and the future directives utilizing different configurations of photoacoustic imaging. Particular emphasis is placed on investigations performed on human or human specimens.

Evaluation of surgically excised breast tissue microstructure using wide-field optical coherence tomography

BACKGROUND

Currently, positive margins at lumpectomy contribute to health care cost, patient anxiety, and treatment delay. Multiple technology solutions are being explored with the aim of lowering re-excision rates for breast-conserving surgery (BCS). We examined wide-field optical coherence tomography (WF-OCT), an innovative adjunct intraoperative imaging tool for tissue visualization of margins.

METHODS

This IRB-approved pilot study included women with invasive or in situ carcinoma scheduled for primary BCS. Lumpectomy specimens and any final/revised margins were imaged by optical coherence tomography immediately prior to standard histological processing. The optical coherence tomography used provided two-dimensional, cross-sectional, real-time depth visualization of the margin widths around excised specimens. A volume of images was captured for 10 × 10 cm tissue surface at high resolution (sub-30 μm) to a depth of 2 mm. Integrated interpretation was performed incorporating final pathology linked with the optical image data for correlation.

RESULTS

Wide-field optical coherence tomography was performed on 185 tissue samples (50 lumpectomy specimens and 135 additional margin shaves) in 50 subjects. Initial diagnosis was invasive ductal carcinoma (IDC) in 10, ductal carcinoma in situ (DCIS) in 14, IDC/DCIS in 22, invasive lobular carcinoma (ILC) in 2, ILC/DCIS in 1, and sarcoma in 1. Optical coherence tomography was concordant with final pathology in 178/185 tissue samples for overall accuracy of 86% and 96.2% (main specimen alone and main specimen + shave margins). Of seven samples that were discordant, 57% (4/7) were considered close (DCIS < 2 mm from margin) per final pathology.

CONCLUSION

Wide-field optical coherence tomography demonstrated concordance with histology at tissue margins, supporting its potential for use as a real-time adjunct intraoperative imaging tool for margin assessment. Further studies are needed for comprehensive evaluation in the intraoperative setting.

Neutral diagnosis: An innovative concept for medical device clinical trials

Study design and statistical analysis are crucial in pivotal clinical trials to evaluate the effectiveness and safety of new medical devices under investigation. In recent years, innovative intraoperative in vivo breast tumor diagnostic devices have been proposed to improve the accuracy and surgical outcomes of breast tumor patients undergoing resection. Although such technologies are promising, investigators need to obtain statistical evidence for the effectiveness and safety of these devices by conducting valid clinical trials. However, the study design and statistical analysis for these clinical trials are complicated. While these trials are designed to provide real-time intraoperative diagnosis of cancerous tissue, they also have clear therapeutic objectives to lower the reoperation rate of breast cancer surgery. This research article introduces the new concept of neutral diagnosis (ND), and the ND clinical trial design as an innovative study design to evaluate the effectiveness and safety of diagnostic devices with direct therapeutic purposes. A joint modeling approach is adopted to make inferences on the effectiveness and safety of these devices for non-neutral diagnosis (non-ND) clinical trials. Simulation studies were conducted to show the efficiency of the ND trials and strength of the joint modeling approach in the non-ND clinical trials. An example on a diagnostic medical device that provides real-time, intraoperative diagnosis of breast cancer tumor tissues during breast cancer surgeries is comprehensively discussed and analyzed.

Complete excision with narrow margins provides equivalent local control to wider excision in breast conservation for invasive cancer

Background

Society of Surgical Oncology and American Society for Radiation Oncology guidelines define clear margins in breast-conserving therapy (BCT) as 'no ink on tumour', in contrast to the attainment of margins of at least 1 mm widely practised in the UK. The primary aim of this study was to explore clinical, surgical and tumour-related factors associated with local recurrence after BCT, with a secondary aim of assessing the impact of margin re-excision on the risk of local recurrence.

Methods

Patient demographics, surgical details, tumour characteristics and local recurrence were recorded for consecutive women with BCT undergoing surgery between January 1997 and January 2007. Margins were defined as clear (greater than 1 mm), close (less than 1 mm but no ink on tumour), reaches (ink on tumour) and clear after re-excision.

Results

A total of 1045 women of median age 54 (range 18-86) years were studied. Median follow-up was 89 (range 4-196) months. Local recurrence occurred in 52 patients (5·0 per cent). Ink on tumour was associated with local recurrence (hazard ratio (HR) 4·86, 95 per cent c.i. 1·49 to 15·79; P = 0·009). Risk of local recurrence was the same for close and clear margins (HR 1·03, 0·40 to 2·62; P = 0·954). In women with involved margins, re-excision was still associated with an increased local recurrence risk (HR 2·50, 1·32 to 4·72; P = 0·005). Oestrogen receptor negativity increased risk (HR 2·28, 1·28 to 4·06; P = 0·005).

Conclusion

Adequately excised margins, even when under 1 mm, provide equivalent outcomes to wider margins in BCT. Achieving complete excision at primary surgery achieves the lowest rates of local recurrence.

Clinical feasibility of optical coherence micro-elastography for imaging tumor margins in breast-conserving surgery

It has been demonstrated that optical coherence micro-elastography (OCME) provides additional contrast of tumor compared to optical coherence tomography (OCT) alone. Previous studies, however, have predominantly been performed on mastectomy specimens. Such specimens typically differ substantially in composition and geometry from the more clinically relevant wide-local excision (WLE) specimens excised during breast-conserving surgery. As a result, it remains unclear if the mechanical contrast observed is maintained in WLE specimens. In this manuscript, we begin to address this issue by performing a feasibility study of OCME on 17 freshly excised, intact WLE specimens. In addition, we present two developments required to sustain the progression of OCME towards intraoperative deployment. First, to enable the rapid visualization of en face images required for intraoperative assessment, we describe an automated segmentation algorithm to fuse en face micro-elastograms with OCT images to provide dual contrast images. Secondly, to validate contrast in micro-elastograms, we present a method that enables co-registration of en face images with histology of WLE specimens, sectioned in the orthogonal plane, without any modification to the standard clinical workflow. We present a summary of the observations across the 17 specimens imaged in addition to representative micro-elastograms and OCT images demonstrating contrast in a number of tumor margins, including those involved by invasive ductal carcinoma, mucinous carcinoma, and solid-papillary carcinoma. The results presented here demonstrate the potential of OCME for imaging tumor margins.

Complementary use of polarization-sensitive and standard OCT metrics for enhanced intraoperative differentiation of breast cancer

We report the development and implementation of an intraoperative polarization-sensitive optical coherence tomography (PS-OCT) system for enhancing breast cancer detection. A total of 3440 PS-OCT images were intraoperatively acquired from 9 human breast specimens diagnosed by H&E histology as healthy fibro-adipose tissue (n = 2), healthy stroma (n = 2), or invasive ductal carcinoma (IDC, n = 5). A standard OCT-based metric (coefficient of variation (CV)) and PS-OCT-based metrics sensitive to biological tissue from birefringence (i.e., retardation and degree of polarization uniformity (DOPU)) were derived from 398 statistically different and independent images selected by correlation coefficient analysis. We found the standard OCT-based metric and PS-OCT-based metrics were complementary for the differentiation of healthy fibro-adipose tissue, healthy stroma, and IDC. While the CV of fibro-adipose tissue was significantly higher (p<0.001) than those of either stroma or IDC, the CV difference between stroma and IDC was minimal. On the other hand, stroma was associated with significantly higher (p<0.001) retardation and significantly lower (p<0.001) DOPU as compared to IDC. By leveraging the complementary information acquired by the intraoperative PS-OCT system, healthy fibro-adipose tissue, healthy stroma, and IDC can be differentiated with an accuracy of 89.4%, demonstrating the potential of PS-OCT as an adjunct modality for enhanced intraoperative differentiation of human breast cancer.

High-speed Intraoperative Assessment of Breast Tumor Margins by Multimodal Ultrasound and Photoacoustic Tomography

Conventional methods for breast tumor margins assessment need a long turnaround time, which may lead to re-operation for patients undergoing lumpectomy surgeries. Photoacoustic tomography (PAT) has been shown to visualize adipose tissue in small animals and human breast. Here, we demonstrate a customized multimodal ultrasound and PAT system for intraoperative breast tumor margins assessment using fresh lumpectomy specimens from 66 patients. The system provides the margin status of the entire excised tissue within 10 minutes. By subjective reading of three researchers, the results show 85.7% [95% confidence interval (CI), 42.0% - 99.2%] sensitivity and 84.6% (95% CI, 53.7% - 97.3%) specificity, 71.4% (95% CI, 30.3% - 94.9%) sensitivity and 92.3% (95% CI, 62.1% - 99.6%) specificity, and 100% (95% CI, 56.1% - 100%) sensitivity and 53.9% (95% CI, 26.1% - 79.6%) specificity respectively when cross-correlated with post-operational histology. Furthermore, a machine learning-based algorithm is deployed for margin assessment in the challenging ductal carcinoma in situ tissues, and achieved 85.5% (95% CI, 75.2% - 92.2%) sensitivity and 90% (95% CI, 79.9% - 95.5%) specificity. Such results present the potential of using mutlimodal ultrasound and PAT as a high-speed and accurate method for intraoperative breast tumor margins evaluation.

Review of methods for intraoperative margin detection for breast conserving surgery

Breast conserving surgery (BCS) is an effective treatment for early-stage cancers as long as the margins of the resected tissue are free of disease according to consensus guidelines for patient management. However, 15% to 35% of patients undergo a second surgery since malignant cells are found close to or at the margins of the original resection specimen. This review highlights imaging approaches being investigated to reduce the rate of positive margins, and they are reviewed with the assumption that a new system would need high sensitivity near 95% and specificity near 85%. The problem appears to be twofold. The first is for complete, fast surface scanning for cellular, structural, and/or molecular features of cancer, in a lumpectomy volume, which is variable in size, but can be large, irregular, and amorphous. A second is for full, volumetric imaging of the specimen at high spatial resolution, to better guide internal radiologic decision-making about the spiculations and duct tracks, which may inform that surfaces are involved. These two demands are not easily solved by a single tool. Optical methods that scan large surfaces quickly are needed with cellular/molecular sensitivity to solve the first problem, but volumetric imaging with high spatial resolution for soft tissues is largely outside of the optical realm and requires x-ray, micro-CT, or magnetic resonance imaging if they can be achieved efficiently. In summary, it appears that a combination of systems into hybrid platforms may be the optimal solution for these two very different problems. This concept must be cost-effective, image specimens within minutes and be coupled to decision-making tools that help a surgeon without adding to the procedure. The potential for optical systems to be involved in this problem is emerging and clinical trials are underway in several of these technologies to see if they could reduce positive margin rates in BCS.

Novel techniques for intraoperative assessment of margin involvement

Breast conserving surgery (BCS) is now the standard of care for the majority of women with early stage breast cancer. There is a finite rate of ipsilateral breast tumour recurrence (IBTR) for breast conserving therapy (BCT) with annual rates of less than 1% for specialist breast practices. There has been recent consensus on the definition of an adequate resection margin for both invasive and noninvasive breast cancer treated with BCS, although some variation in margin policy persists with definitions of 'no tumour at ink', 1 and 2 mm margin mandates. Despite the development of methods for intraoperative assessment of margins, up to 20% of patients require further surgery (cavity re-excision or completion mastectomy) to achieve clear surgical margins. In the past decade, several novel technologies for intraoperative margin assessment have been explored with the aim of reducing rates of re-operation and its attendant patient anxiety, inconvenience and additional cost. Ongoing studies are addressing the safety, feasibility and cost-effectiveness of these novel technologies relative to methods in routine clinical usage.

Current margin practice and effect on re-excision rates following the publication of the SSO-ASTRO consensus and ABS consensus guidelines: a national prospective study of 2858 women undergoing breast-conserving therapy in the UK and Ireland

INTRODUCTION

There is variation in margin policy for breast conserving therapy (BCT) in the UK and Ireland. In response to the Society of Surgical Oncology and American Society for Radiation Oncology (SSO-ASTRO) margin consensus ('no ink on tumour' for invasive and 2 mm for ductal carcinoma in situ [DCIS]) and the Association of Breast Surgery (ABS) consensus (1 mm for invasive and DCIS), we report on current margin practice and unit infrastructure in the UK and Ireland and describe how these factors impact on re-excision rates.

METHODS

A trainee collaborative-led multicentre prospective study was conducted in the UK and Ireland between 1st February and 31st May 2016. Data were collected on consecutive BCT patients and on local infrastructure and policies.

RESULTS

A total of 79 sites participated in the data collection (75% screening units; average 372 cancers annually, range 70-900). For DCIS, 53.2% of units accept 1 mm and 38% accept 2-mm margins. For invasive disease 77.2% accept 1 mm and 13.9% accept 'no ink on tumour'. A total of 2858 patients underwent BCT with a mean re-excision rate of 17.2% across units (range 0-41%). The re-excision rate would be reduced to 15% if all units applied SSO-ASTRO guidelines and to 14.8% if all units followed ABS guidelines. Of those who required re-operation, 65% had disease present at margin.

CONCLUSION

There continues to be large variation in margin policy and re-excision rates across units. Altering margin policies to follow either SSO-ASTRO or ABS guidelines would result in a modest reduction in the national re-excision rate. Most re-excisions are for involved margins rather than close margins.

Achieving clear margins. Directed shaving using MarginProbe, as compared to a full cavity shave approach

BACKGROUND

Following lumpectomy, full cavity shaving approach is used to reduce positive margin rates, among other issues previously studied by others, at an expense of increase in tissue volume removed. We present our experience after switching from full cavity shaving to a targeted shaving approach using MarginProbe, an intra-operative margin assessment device.

METHODS

Specimen excision was performed according to standard of care. Additional shavings were taken based on device readings on the lumpectomy specimen. Intra-operative imaging was used, as required.

RESULTS

We compared 137 MarginProbe cases to 199 full cavity shave cases. The re-excision rate was reduced by 57% (P = 0.026), from 15.1% to 6.6%. The overall tissue volume removed was reduced by 32% (P = 0.0023), from 115 cc to 78 cc.

CONCLUSIONS

MarginProbe enabled a change in the lumpectomy technique from full cavity shavings to directed shavings guided by the device. There was a significant reduction in re-excisions and in the overall tissue volume removed.The lower amount of shavings also contributed to a reduction in pathology work.

G. B, Sebastian P, Somananthan T, Maliekal TT. TM1-IR680 peptide for assessment of surgical margin and lymph node metastasis in murine orthotopic model of oral cancer

Treatment outcome after surgical removal in oral carcinoma is poor due to inadequate methodologies available for marking surgical margins. Even though some methodologies for intraoperative margin assessment are under clinical and preclinical trials for other solid tumours, a promising modality for oral cancer surgery is not developed. Fluorescent-based optical imaging using Near Infrared (NIR) dyes tagged to tumour specific target will be an optimal tool for this purpose. One such target, Gastrin Releasing Peptide Receptor (GRPR) was selected for the study, and its binding peptide, TM1-IR680, was tested for its efficacy for surgical margin prediction in murine orthotopic model of oral cancer, derived from primary samples. Here, for the first time in a preclinical analysis, we show that the size and margin of oral cancer can be predicted, as revealed by 3D-imaging. Interestingly, the peptide was sensitive enough to detect lymph nodes that harboured dispersed tumour cells before colonization, which was impossible to identify by conventional histopathology. We recommend the use of TM1-NIR dyes alone or in combination with other technologies to improve the clinical outcome of oral cancer surgery.

Intra-operative assessment of excised breast tumour margins using ClearEdge imaging device

INTRODUCTION

Breast conserving surgery (BCS) aims to remove a breast cancer completely and obtain clear margins. Complete excision is essential to reduce the risk of local recurrence. The ClearEdge™ (CE) imaging device examines margins of excised breast tissue intra-operatively. The aim of this study was to investigate the potential of the device in detecting margin involvement in patients having BCS.

METHODS

In Phase-1 58 patients underwent BCS and had 334 margins assessed by the device. In Phase-2 the device was used in 63 patients having BCS and 335 margins were assessed. Patients with margins considered close or involved by the CE device were re-excised.

RESULTS

The margin assessment accuracies in Phase-1 and Phase-2 compared to permanent section pathology were very similar: sensitivity (84.3% and 87.3%), specificity (81.9% and 75.6%), positive predictive value (67.2% and 63.6%), and negative predictive value (92.2% and 92.4%). The false positive rate (18.1% and 24.4%) and false negative rate (15.7% and 12.7%) were low in both phases. In Phase-2 re-excision rate was 37%, but in the 54 where the CE device was used appropriately the re-excision rate was 17%. Had all surgeons interpreted all images appropriately and re-excised margins detected as abnormal by the device in Phase-2 then the re-excision rate would have been 7%.

CONCLUSION

This study shows that the CE device has potential to reduce re-excision after BCS and further randomized studies of its value are warranted.

The importance of surgical margins in breast cancer

Achieving negative margins with "no tumor on ink" is an appropriate goal in breast conserving therapy (BCT). Wider margins do not decrease recurrence rates, and re-excision in patients with microscopic positive margins is warranted. Several strategies exist to increase rates of negative margins, including techniques to improve tumor localization, intraoperative assessment of margins and oncoplastic techniques. Negative margins should be the goal of BCT, as this will improve both local control and long-term survival.

The impact of use of an intraoperative margin assessment device on re-excision rates

Historically there has been a high rate of surgical interventions to obtain clear margins for breast cancer patients undergoing breast conserving local therapy. An intraoperative margin assessment tool (MarginProbe) has been approved for use in the US since 2013. This study is the first compilation of data from routine use of the device, to assess the impact of device utilization on re-excision rates. We present a retrospective, observational, review from groups of consecutive patients, before and after the implementation of intraoperative use of the device during lumpectomy procedures. Lesions were localized by standard methods. The intraoperative margin assessment device was used on all circumferential margins of the main specimen, but not on any additional shavings. A positive reading by the device led to an additional shaving of the corresponding cavity location. Specimens were also, when feasible, imaged intra-operatively by X-ray, and additional shavings were taken if needed based on clinical assessment. For each surgeon, historical re-excision rates were established based on a consecutive set of patients from a time period proximal to initiation of use of the device. From March 2013 to April 2014 the device was routinely used by 4 surgeons in 3 centers. In total, 165 cases lumpectomy cases were performed. Positive margins resulted in additional re-excision procedures in 9.7% (16/165) of the cases. The corresponding historical set from 2012 and 2013 consisted of 186 Lumpectomy cases, in which additional re-excision procedures were performed in 25.8% (48/186) of the cases. The reduction in the rate of re-excision procedures was significant 62% (P < 0.0001). Use of an intraoperative margin assessment device contributes to achieving clear margins and reducing re-excision procedures. As in some cases positive margins were found on shavings, future studies of interest may include an analysis of the effect of using the device on the shavings intra-operatively.

Techniques for intraoperative radiation therapy for early-stage breast carcinoma

ABSTRACT 

Intraoperative radiation therapy (IORT) is a method of accelerated partial breast irradiation developed to replace other longer courses of radiotherapy with a single radiation session administered at the time of breast-conserving surgery. The purpose of this review is to summarize the advantages and disadvantages of breast IORT techniques that are currently available, as well to consider potential alternative techniques for breast IORT or ultra-short course breast radiotherapy. Furthermore, we highlight the published outcomes for the IORT treatment approaches including: electron therapy, superficial photon therapy and other techniques. Potential future directions of IORT are explored including novel IORT techniques utilizing intraoperative brachytherapy with in-room imaging and rapid treatment planning.

Assessing breast tumor margin by multispectral photoacoustic tomography

An unmet need exists in high-speed and highly-sensitive intraoperative assessment of breast cancer margin during conservation surgical procedures. Here, we demonstrate a multispectral photoacoustic tomography system for breast tumor margin assessment using fat and hemoglobin as contrasts. This system provides ~3 mm tissue depth and ~125 μm axial resolution. The results agreed with the histological findings. A high sensitivity in margin assessment was accomplished, which opens a compelling way to intraoperative margin assessment.

Intraoperative assessment of margins in breast conservative surgery--still in use?

A positive margin in breast conserving surgery is associated with an increased risk of local recurrence. Failure to achieve clear margins results in re-excision procedures. Methods for intraoperative assessment of margins have been developed, such as frozen section analysis, touch preparation cytology, near-infrared fluorescence optical imaging, x-ray diffraction technology, high-frequency ultrasound, micro-CT, and radiofrequency spectroscopy. In this article, options that might become the method of choice in the future are discussed.

A randomized prospective study of lumpectomy margin assessment with use of MarginProbe in patients with nonpalpable breast malignancies

Background

The presence of tumor cells at the margins of breast lumpectomy specimens is associated with an increased risk of ipsilateral tumor recurrence. Twenty to 30 % of patients undergoing breast-conserving surgery require second procedures to achieve negative margins. This study evaluated the adjunctive use of the MarginProbe device (Dune Medical Devices Ltd, Caesarea, Israel) in providing real-time intraoperative assessment of lumpectomy margins.

Methods

This multicenter randomized trial enrolled patients with nonpalpable breast malignancies. The study evaluated MarginProbe use in addition to standard intraoperative methods for margin assessment. After specimen removal and inspection, patients were randomized to device or control arms. In the device arm, MarginProbe was used to examine the main lumpectomy specimens and direct additional excision of positive margins. Intraoperative imaging was used in both arms; no intraoperative pathology assessment was permitted.

Results

In total, 596 patients were enrolled. False-negative rates were 24.8 and 66.1 % and false-positive rates were 53.6 and 16.6 % in the device and control arms, respectively. All positive margins on positive main specimens were resected in 62 % (101 of 163) of cases in the device arm, versus 22 % (33 of 147) in the control arm (p < 0.001). A total of 19.8 % (59 of 298) of patients in the device arm underwent a reexcision procedure compared with 25.8 % (77 of 298) in the control arm (6 % absolute, 23 % relative reduction). The difference in tissue volume removed was not significant.

Conclusions

Adjunctive use of the MarginProbe device during breast-conserving surgery improved surgeons’ ability to identify and resect positive lumpectomy margins in the absence of intraoperative pathology assessment, reducing the number of patients requiring reexcision. MarginProbe may aid performance of breast-conserving surgery by reducing the burden of reexcision procedures for patients and the health care system.

Intraoperative assessment of margins in breast conserving therapy: a systematic review

Approximately one quarter of patients undergoing breast conserving therapy for breast cancer will require a second operation to achieve adequate clearance of the margins. A number of techniques to assess margins intraoperatively have been reported. This systematic review examines current intraoperative methods for assessing margin status. The final pathology status, statistical measures including accuracy of tumour margin assessment, average time impact on the procedure and second operation rate, were used as criteria for comparison between studies. Although pathological methods, such as frozen section and imprint cytology performed well, they added on average 20-30 min to operation times. An ultrasound probe allows accurate examination of the margins and delivers results in a timely manner, yet it has a limited role with DCIS where calcification is present and in multifocal cancer. Further research is required in other intraoperative margin assessment techniques, such as mammography, radiofrequency spectroscopy and optical coherence tomography.