Accuracy of intraoperative frozen-section analysis of breast cancer lumpectomy-bed margins

Impact of intraoperative specimen mammography on margins in breast-conserving surgery

A positive resection margin is one of the most significant risk factors for local breast cancer recurrence following breast-conserving surgery (BCS). Intraoperative specimen mammography (SMMG) is routinely used to evaluate the surgical margin at our institution. The aim of the present study was to assess the adequacy of SMMG for margin assessment. The patient cohort included 174 women who underwent BCS in 2006. The sensitivity and specificity of SMMG were assessed by comparing the margins assessed by histological and radiological methods. It was also examined whether the rate of positive histological margins was decreased by re-excision following SMMG evaluation. A total of 23 false-negatives and 6 false-positives were determined by SMMG. The sensitivity and specificity of SMMG margin assessment for patients with primary breast cancer were 20.6 and 94.6%, respectively. The positive predictive value was 50% and the negative predictive value was 82.2%. A subgroup analysis revealed that the sensitivity and specificity of SMMG in cases with ductal carcinoma in situ (DCIS) were higher compared with those in invasive ductal carcinoma. Furthermore, the positive histological margin rate was not affected by re-excision. Although the general usefulness of intraoperative SMMG was not proven, this procedure may be useful in specific cases, particularly those with DCIS and those diagnosed by stereotactic biopsy. A prospective study with exact criteria and a standard procedure is required.

The Role of Intraoperative Pathologic Assessment in the Surgical Management of Ductal Carcinoma In Situ

BACKGROUND

Re-excision surgeries for the treatment of ductal carcinoma in situ (DCIS) put a strain on patients and healthcare resources; however, intraoperative pathologic assessment of DCIS may lead to a reduction in these additional surgeries. This study examined the relationship between intraoperative pathologic assessment and subsequent operations in patients with a diagnosis of DCIS.

METHODS

Surveillance, Epidemiology, and End Results-Medicare patients diagnosed with DCIS from 1999 to 2007 who initially underwent partial mastectomy, without axillary surgery, were included in this study. Use of intraoperative frozen section or touch preparation during the initial surgery was assessed. Multivariable logistic regression was used to describe the relationship between the use of intraoperative pathologic assessment and any subsequent mastectomy or partial mastectomy within 90 days of the initial partial mastectomy.

RESULTS

Of 8259 DCIS patients, 3509 (43 %) required a second surgery, and intraoperative pathologic assessment was performed for 2186 (26 %). Intraoperative pathologic assessment had no statistically significant effect on whether or not a subsequent breast surgery occurred (adjusted odds ratio 1.07, 95 % confidence interval 0.95-1.21; p = 0.293). Patient residence in a rural area, tumor size ≥2 cm, and poorly differentiated tumor grade were associated with a greater likelihood of subsequent surgery, while age 80 years and older was associated with a lower likelihood of subsequent surgery.

CONCLUSIONS

The use of intraoperative frozen section or touch preparation during partial mastectomy from 1999 to 2007 was not associated with a reduction in subsequent breast operations in women with DCIS. These results highlight the need to identify cost-effective tools and strategies to reduce the need for additional surgery in patients with DCIS.

Wide-field tissue polarimetry allows efficient localized mass spectrometry imaging of biological tissues

While mass spectrometers can detect chemical signatures within milliseconds of data acquisition time, the non-targeted nature of mass spectrometry imaging (MSI) necessitates probing the entire surface of the sample to reveal molecular composition even if the information is only sought from a sample subsection. This leads to long analysis times. Here, we used polarimetry to identify, within a biological tissue, areas of polarimetric heterogeneity indicative of cancer. We were then able to target our MS analysis using polarimetry results to either the cancer region itself or to the cancer margin. A tandem of polarimetry and Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI) enables fast (10 fold compared to non-targeted imaging), and accurate pathology assessment (cancer typification in less than 2 minutes compared to 30 minutes for histopathology) of ex vivo tissue slices, without additional sample preparation. This workflow reduces the overall analysis time of MSI as a research tool.

Design and implementation of coded aperture coherent scatter spectral imaging of cancerous and healthy breast tissue samples

A scatter imaging technique for the differentiation of cancerous and healthy breast tissue in a heterogeneous sample is introduced in this work. Such a technique has potential utility in intraoperative margin assessment during lumpectomy procedures. In this work, we investigate the feasibility of the imaging method for tumor classification using Monte Carlo simulations and physical experiments. The coded aperture coherent scatter spectral imaging technique was used to reconstruct three-dimensional (3-D) images of breast tissue samples acquired through a single-position snapshot acquisition, without rotation as is required in coherent scatter computed tomography. We perform a quantitative assessment of the accuracy of the cancerous voxel classification using Monte Carlo simulations of the imaging system; describe our experimental implementation of coded aperture scatter imaging; show the reconstructed images of the breast tissue samples; and present segmentations of the 3-D images in order to identify the cancerous and healthy tissue in the samples. From the Monte Carlo simulations, we find that coded aperture scatter imaging is able to reconstruct images of the samples and identify the distribution of cancerous and healthy tissues (i.e., fibroglandular, adipose, or a mix of the two) inside them with a cancerous voxel identification sensitivity, specificity, and accuracy of 92.4%, 91.9%, and 92.0%, respectively. From the experimental results, we find that the technique is able to identify cancerous and healthy tissue samples and reconstruct differential coherent scatter cross sections that are highly correlated with those measured by other groups using x-ray diffraction. Coded aperture scatter imaging has the potential to provide scatter images that automatically differentiate cancerous and healthy tissue inside samples within a time on the order of a minute per slice.

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

A Fluorescence-Guided Laser Ablation System for Removal of Residual Cancer in a Mouse Model of Soft Tissue Sarcoma

The treatment of soft tissue sarcoma (STS) generally involves tumor excision with a wide margin. Although advances in fluorescence imaging make real-time detection of cancer possible, removal is limited by the precision of the human eye and hand. Here, we describe a novel pulsed Nd:YAG laser ablation system that, when used in conjunction with a previously described molecular imaging system, can identify and ablate cancer in vivo. Mice with primary STS were injected with the protease-activatable probe LUM015 to label tumors. Resected tissues from the mice were then imaged and treated with the laser using the paired fluorescence-imaging/ laser ablation device, generating ablation clefts with sub-millimeter precision and minimal underlying tissue damage. Laser ablation was guided by fluorescence to target tumor tissues, avoiding normal structures. The selective ablation of tumor implants in vivo improved recurrence-free survival after tumor resection in a cohort of 14 mice compared to 12 mice that received no ablative therapy. This prototype system has the potential to be modified so that it can be used during surgery to improve recurrence-free survival in patients with cancer.

Tailoring Adjuvant Radiation Therapy by Intraoperative Imaging to Detect Residual Cancer

For many solid cancers, radiation therapy is offered as an adjuvant to surgical resection to lower rates of local recurrence and improve survival. However, a subset of patients treated with surgery alone will not have a local recurrence. Currently, there is no way to accurately determine which patients have microscopic residual disease in the tumor bed after surgery and therefore are most likely to benefit from adjuvant radiation therapy. To address this problem, a number of technologies have been developed to try to improve margin assessment of resected tissue and to detect residual cancer in the tumor bed. Moreover, some of these approaches have been translated from the preclinical arena into clinical trials. Here, we review different types of intraoperative molecular imaging systems for cancer. Optical imaging techniques like epi-illumination, fluorescence molecular tomography and optoacoustic imaging can be coupled with exogenous fluorescent imaging probes that accumulate in tumors passively via the enhanced permeability and retention effect or are targeted to tumor tissues based on affinity or enzyme activity. In these approaches, detection of fluorescence in the tumor bed may indicate residual disease. Protease activated probes have generated great interest because of their potential for leading to high tumor to normal contrast. Recently, the first Phase I clinical trial to assess the safety and activation of a protease activated probe was conducted. Spectroscopic methods like radiofrequency spectroscopy and Raman spectroscopy, which are based on energy absorption and scattering, respectively, have also been tested in humans and are able to distinguish between normal and tumors tissues intraoperatively. Most recently, multimodal contrast agents have been developed that target tumors and contain both fluorescent dyes and magnetic resonance imaging contrast agents, allowing for preoperative planning and intraoperative margin assessment with a single contrast agent. Further clinical testing of these various intraoperative imaging approaches may lead to more accurate methods for margin assessment and the intraoperative detection of microscopic residual disease, which could guide further resection and the use of adjuvant radiation therapy.

Toolbox to Reduce Lumpectomy Reoperations and Improve Cosmetic Outcome in Breast Cancer Patients: The American Society of Breast Surgeons Consensus Conference

BACKGROUND

Multiple recent reports have documented significant variability of reoperation rates after initial lumpectomy for breast cancer. To address this issue, a multidisciplinary consensus conference was convened during the American Society of Breast Surgeons 2015 annual meeting.

METHODS

The conference mission statement was to "reduce the national reoperation rate in patients undergoing breast conserving surgery for cancer, without increasing mastectomy rates or adversely affecting cosmetic outcome, thereby improving value of care." The goal was to develop a toolbox of recommendations to reduce the variability of reoperation rates and improve cosmetic outcomes. Conference participants included providers from multiple disciplines involved with breast cancer care, as well as a patient representative. Updated systematic reviews of the literature and invited presentations were sent to participants in advance. After topic presentations, voting occurred for choice of tools, level of evidence, and strength of recommendation.

RESULTS

The following tools were recommended with varied levels of evidence and strength of recommendation: compliance with the SSO-ASTRO Margin Guideline; needle biopsy for diagnosis before surgical excision of breast cancer; full-field digital diagnostic mammography with ultrasound as needed; use of oncoplastic techniques; image-guided lesion localization; specimen imaging for nonpalpable cancers; use of specialized techniques for intraoperative management, including excisional cavity shave biopsies and intraoperative pathology assessment; formal pre- and postoperative planning strategies; and patient-reported outcome measurement.

CONCLUSIONS

A practical approach to performance improvement was used by the American Society of Breast Surgeons to create a toolbox of options to reduce lumpectomy reoperations and improve cosmetic outcomes.

Rapid intraoperative visualization of breast lesions with γ-glutamyl hydroxymethyl rhodamine green

We previously developed γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) as a tool to detect viable cancer cells, based on the fact that the enzyme γ-glutamyltranspeptidase (GGT) is overexpressed on membranes of various cancer cells, but is not expressed in normal tissue. Cleavage of the probe by GGT generates green fluorescence. Here, we examined the feasibility of clinical application of gGlu-HMRG during breast-conserving surgery. We found that fluorescence derived from cleavage of gGlu-HMRG allowed easy discrimination of breast tumors, even those smaller than 1 mm in size, from normal mammary gland tissues, with 92% sensitivity and 94% specificity, within only 5 min after application. We believe this rapid, low-cost method represents a breakthrough in intraoperative margin assessment during breast-conserving surgery.

Standardized processing of native tissue in breast pathology

In breast surgery, replacement of intraoperative frozen section by core needle and vacuum biopsies hampers collections of unfixed breast specimens. We practice immediate intraoperative macroscopic analysis of resection margins and vacuum-cooling of breast specimens to enable native tissue asservation for assessment of biological markers and tissue banking of tumor tissue. In addition, slicing of native tissue before formalin fixation guarantees a standardized and uniform fixation. Starting in 2013, more than 350 breast specimens were processed as native specimens in the Institute of Pathology of Hannover Medical School. Breast specimens with an invasive carcinoma and request of an intraoperative resection margin assessment were processed with an immediate intraoperative pathological analysis. All other breast specimens without assessment of an intraoperative resection margin were vacuum-fixed processed. In all cases, native tissue for biomarker analyses and tumor banking could be preserved.

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.

Assessment of breast pathologies using nonlinear microscopy

Rapid intraoperative assessment of breast excision specimens is clinically important because up to 40% of patients undergoing breast-conserving cancer surgery require reexcision for positive or close margins. We demonstrate nonlinear microscopy (NLM) for the assessment of benign and malignant breast pathologies in fresh surgical specimens. A total of 179 specimens from 50 patients was imaged with NLM using rapid extrinsic nuclear staining with acridine orange and intrinsic second harmonic contrast generation from collagen. Imaging was performed on fresh, intact specimens without the need for fixation, embedding, and sectioning required for conventional histopathology. A visualization method to aid pathological interpretation is presented that maps NLM contrast from two-photon fluorescence and second harmonic signals to features closely resembling histopathology using hematoxylin and eosin staining. Mosaicking is used to overcome trade-offs between resolution and field of view, enabling imaging of subcellular features over square-centimeter specimens. After NLM examination, specimens were processed for standard paraffin-embedded histology using a protocol that coregistered histological sections to NLM images for paired assessment. Blinded NLM reading by three pathologists achieved 95.4% sensitivity and 93.3% specificity, compared with paraffin-embedded histology, for identifying invasive cancer and ductal carcinoma in situ versus benign breast tissue. Interobserver agreement was κ = 0.88 for NLM and κ = 0.89 for histology. These results show that NLM achieves high diagnostic accuracy, can be rapidly performed on unfixed specimens, and is a promising method for intraoperative margin assessment.

The value of intraoperative frozen section analysis for margin status in breast conservation surgery in a nontertiary institution

Introduction. Breast conservation treatment (BCT) for early-stage breast malignancies requires negative margins and good cosmesis. Reoperations may be needed to achieve negative margins, which can have an adverse impact on outcomes. This study was performed to evaluate the efficacy of intraoperative frozen section analysis (IFSA) for margin assessment to reduce excision rates. Methods. All patients treated at the authors' private healthcare facility between 2009 and 2011 for breast cancer were included in the study. Those for whom BCT was intended underwent wide excision with IFSA. Six margins of the excised tissue, and the sentinel lymph node (SLN), where appropriate, were submitted for IFSA. Patient demographics, tumour characteristics, number of operations performed, and outcomes were analysed. Results. Of the 161 patients analysed, 138 (85.7%) had successful breast conservation. Four patients required a reoperation for incomplete surgical extirpation. One had a false negative SLN assessment on IFSA, and was returned to the operating room for an axillary dissection. Three patients required reoperations for inadvertently missed multicentric disease. None had false negative margin evaluation with IFSA necessitating reexcision. Conclusion. The use of IFSA allows low rates of reoperation with BCT. Further research is needed to establish consistency in low reexcision rates for cost-effectiveness and optimum resource allocation.

Oncoplastic breast surgery: indications, techniques and perspectives

Breast-conservation surgery (BCS) is established as a safe option for most women with early breast cancer. Recently, advances in oncoplastic techniques have reduced surgical trauma and thus are capable of preserving the breast form and quality of life. In spite of the most BCS defects can be managed with primary closure, the aesthetic outcome may be unpredictable. Oncoplastic reconstruction may begin at the time of BCS (immediate), weeks (delayed-immediate) or months to years afterwards (delayed). With immediate reconstruction, the surgical process is smooth, since both procedures can be associated in one operative setting. Additionally, it permits wider excision of the tumor, with a superior mean volume of the specimen and potentially reducing the incidence of margin involvement. The oncoplastic techniques are related to volume displacement or replacement procedures including local flaps, latissimus dorsi myocutaneous flap and reduction mammaplasty/masthopexy. Regardless of the fact that there is no consensus concerning the best approach, the criteria are determined by the surgeon's experience and the size of the defect in relation to the size of the remaining breast. On the basis of our 15-year experience, it is possible to identify trends in types of breast defects and to develop an algorithm for immediate BCS reconstruction on the basis of the initial breast volume, the extent/location of glandular tissue ressection and the remaining available breast tissue. The main advantages of the technique utilized should include reproducibility, low interference with the oncologic treatment and long-term results. Surgical planning should include the patients's preferences, and chiefly addressing individual reconstructive requirements, enabling each patient to receive an individual "custom-made" reconstruction.

Polarization-sensitive multimodal imaging for detecting breast cancer

Intraoperative delineation of breast cancer is a significant problem in surgical oncology. A reliable method for demarcation of malignant breast tissue during surgery would reduce the re-excision rate due to positive margins. We present a novel method of identifying breast cancer margins using combined dye-enhanced wide-field fluorescence polarization imaging for en face cancer margins and polarization-sensitive (PS) optical coherence tomography (OCT) for cross-sectional evaluation. Tumor specimens were collected following breast surgery, stained with methylene blue, and imaged. Wide-field fluorescence polarization images were excited at 640 nm and registered between 660 and 750 nm. Standard and PS OCT images were acquired using a commercial 1,310-nm swept-source system. The imaging results were validated against histopathology. Statistically significant higher fluorescence polarization of cancer as compared with both normal and fibrocystic tumor tissue was measured in all the samples. Fluorescence polarization delineated lateral breast cancer margins with contrast superior to that provided by OCT. However, OCT complemented fluorescence polarization imaging by facilitating cross-sectional inspection of tissue. PS OCT yielded higher contrast between cancer and connective tissue, as compared with standard OCT. Combined PS OCT and fluorescence polarization imaging shows promise for intraoperative delineation of breast cancer.

Fluorescent-tilmanocept for tumor margin analysis in the mouse model

BACKGROUND

Dendritic cells (DC) are localized in close proximity to cancer cells in many well-known tumors, and thus maybe a useful target for tumor margin assessment.

MATERIALS AND METHODS

[(99m)Tc]- cyanine 7 (Cy7)-tilmanocept was synthesized and in vitro binding assays to bone marrow-derived DC were performed. Fifteen mice, implanted with either 4T1 mouse mammary or K1735 mouse melanoma tumors, were administered 1.0 nmol of [(99m)Tc]-Cy7-tilmanocept via tail vein injection. After fluorescence imaging 1 or 2 h after injection, the tumor, muscle, and blood were assayed for radioactivity to calculate percent-injected dose. Digital images of the tumors after immunohistochemical staining for DC were analyzed to determine DC density.

RESULTS

In vitro binding demonstrated subnanomolar affinity of [(99m)Tc]-Cy7-tilmanocept to DC (KA = 0.31 ± 0.11 nM). After administration of [(99m)Tc]-Cy7-tilmanocept, fluorescence imaging showed a 5.5-fold increase in tumor signal as compared with preinjection images and a 3.3-fold difference in fluorescence activity when comparing the tumor with the surgical bed after tumor excision. Immunohistochemical staining analysis demonstrated that DC density positively correlated with tumor percent of injected dose per gram (r = 0.672, P = 0.03), and higher DC density was observed at the periphery versus center of the tumor (186 ± 54 K versus 64 ± 16 K arbitrary units, P = 0.001).

CONCLUSIONS

[(99m)Tc]-Cy7-tilmanocept exhibits in vitro and in vivo tumor-specific binding to DC and maybe useful as a tumor margin targeting agent.

Perioperative measures to optimize margin clearance in breast conserving surgery

Margin status is one of the most important determinants of local recurrence following breast conserving surgery. The fact that up to 60% of patients undergoing breast conserving surgery require re-excision highlights the importance of optimizing margin clearance. In this review we summarize the following perioperative measures that aim to enhance margin clearance: (1) patient risk stratification, specifically risk factors and nomograms, (2) preoperative imaging, (3) intraoperative techniques including wire-guided localization, radioguided surgery, intraoperative ultrasound-guided resection, intraoperative specimen radiography, standardized cavity shaving, and ink-directed focal re-excision; (4) and intraoperative pathology assessment techniques, namely frozen section analysis and imprint cytology. Novel surgical techniques as well as emerging technologies are also reviewed. Effective treatment requires accurate preoperative planning, developing and implementing a consistent definition of margin clearance, and using tools that provide detailed real-time intraoperative information on margin status.

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

In breast conserving surgery, the tumor should be removed with a clean margin, a rim of healthy tissue surrounding. Failure to achieve clean margins in the initial surgery results in a re-excision procedure. Re-excision rates are reported as being 11-46% for invasive carcinoma and ductal carcinoma in situ (DCIS). Re-excisions can have negative consequences such as increased postoperative infections, negative impact on cosmesis, patient anxiety and increased medical costs. Therefore, the surgical margin of invasive and intraductal (DCIS) breast tissue is a subject of intense discussion. Different options for intraoperative assessment are available, but all in all, they are unsatisfying. Frozen section margin examination is possible but is time consuming and restricted to the assessment of invasive carcinoma. In the case of DCIS, there is no procedure for intraoperative margin assessment. Thus, a solution for efficient intraoperative surgical margin assessment is needed. For this purpose, an innovative, real-time, intraoperative margin-assessment device (MarginProbe, Dune Medical Devices, Caesarea, Israel) was designed, and recent published clinical data reported a reduction of re-excisions by more than 50%.

Current aspects of therapeutic reduction mammaplasty for immediate early breast cancer management: An update

Breast-conservation surgery (BCS) is established as a safe surgical treatment for most patients with early breast cancer. Recently, advances in oncoplastic techniques are capable of preserving the breast form and quality of life. Although most BCS defects can be managed with primary closure, the aesthetic outcome may be unpredictable. Among technical options, therapeutic reduction mammaplasty (TRM) remains a useful procedure since the BCS defect can be repaired and the preoperative appearance can be improved, resulting in more proportional breasts. As a consequence of rich breast tissue vascularization, the greater part of reduction techniques have based their planning on preserving the pedicle of the nipple-areola complex after tumor removal. Reliable circulation and improvement of a conical shape to the breast are commonly described in TRM reconstructions. With an immediate approach, the surgical process is smooth since both procedures can be carried out in one operative setting. Additionally, it permits wider excision of the tumor, with a superior mean volume of the specimen and potentially reduces the incidence of margin involvement. Regardless of the fact that there is no consensus concerning the best TRM technique, the criteria is determined by the surgeon’s experience, the extent/location of glandular tissue resection and the size of the defect in relation to the size of the remaining breast. The main advantages of the technique utilized should include reproducibility, low interference with the oncological treatment and long-term results. The success of the procedure depends on patient selection, coordinated planning and careful intra-operative management.

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.

Delineating breast ductal carcinoma using combined dye-enhanced wide-field polarization imaging and optical coherence tomography

Intra-operative delineation of breast cancer is a challenging problem. We used dye-enhanced wide-field polarization imaging for rapid demarcation of en face cancer margins and optical coherence tomography (OCT) for cross-sectional evaluation. Ductal carcinoma specimens were stained with methylene blue. Wide-field reflectance images were acquired at 440 and 640 nm. Wide-field fluorescence images were excited at 640 nm and registered between 660 nm and 750 nm. OCT images were acquired using a 1310 nm swept-source system. The results were validated against histopathology. Both imaging modalities provided diagnostic information on cancer margins. Combined OCT and wide-field polarization imaging shows promise for intra-operative detection of ductal breast carcinoma.

Large field, high resolution full-field optical coherence tomography: a pre-clinical study of human breast tissue and cancer assessment

We present a benchmark pilot study in which high-resolution Full-Field Optical Coherence Tomography (FF-OCT) was used to image human breast tissue and is evaluated to assess its ability to aid the pathologist’s management of intra-operative diagnoses. FF-OCT imaging safety was investigated and agreement between FF-OCT and routinely prepared histopathological images was evaluated. The compact setup used for this study provides 1 µm³ resolution and 200 µm imaging depth, and a 2.25 cm² specimen is scanned in about 7 minutes. 75 breast specimens were imaged from 22 patients (21 women, 1 man) with a mean age of 58 (range: 25-83). Pathologists blind diagnosed normal/benign or malignant tissue based on FF-OCT images alone, diagnosis from histopathology followed for comparison. The contrast in the FF-OCT images is generated by intrinsic tissue scattering properties, meaning that no tissue staining or preparation is required. Major architectural features and tissue structures of benign breast tissue, including adipocytes, fibrous stroma, lobules and ducts were characterized. Subsequently, features resulting from pathological modification were characterized and a diagnosis decision tree was developed. Using FF-OCT images, two breast pathologists were able to distinguish normal/benign tissue from lesional with a sensitivity of 94% and 90%, and specificity of 75% and 79% respectively.

A pilot study evaluating shaved cavity margins with micro-computed tomography: a novel method for predicting lumpectomy margin status intraoperatively

Microscopically clear lumpectomy margins are essential in breast conservation, as involved margins increase local recurrence. Currently, 18-50% of lumpectomies have close or positive margins that require re-excision. We assessed the ability of micro-computed tomography (micro-CT) to evaluate lumpectomy shaved cavity margins (SCM) intraoperatively to determine if this technology could rapidly identify margin involvement by tumor and reduce re-excision rates. Twenty-five SCM from six lumpectomies were evaluated with a Skyscan 1173 table top micro-CT scanner (Skyscan, Belgium). Micro-CT results were compared to histopathological results. We scanned three SCM at once with a 7-minute scanning protocol, and studied a total of 25 SCM from six lumpectomies. Images of the SCM were evaluated for radiographic signs of breast cancer including clustered microcalcifications and spiculated masses. SCM were negative by micro-CT in 19/25 (76%) and negative (≥2 mm) by histopathology in 19/25 (76%). Margin status by micro-CT was concordant with histopathology in 23/25 (92%). Micro-CT overestimated margin involvement in 1/25 and underestimated margin involvement in 1/25. Micro-CT had an 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for evaluation of SCM. Evaluation of SCM by micro-CT is an accurate and promising method of intraoperative margin assessment in breast cancer patients. The scanning time required is short enough to permit real-time feedback to the operating surgeon, allowing immediate directed re-excision.

Advancing optical imaging for breast margin assessment: an analysis of excisional time, cautery, and patent blue dye on underlying sources of contrast

Breast conserving surgery (BCS) is a recommended treatment for breast cancer patients where the goal is to remove the tumor and a surrounding rim of normal tissue. Unfortunately, a high percentage of patients return for additional surgeries to remove all of the cancer. Post-operative pathology is the gold standard for evaluating BCS margins but is limited due to the amount of tissue that can be sampled. Frozen section analysis and touch-preparation cytology have been proposed to address the surgical needs but also have sampling limitations. These issues represent an unmet clinical need for guidance in resecting malignant tissue intra-operatively and for pathological sampling. We have developed a quantitative spectral imaging device to examine margins intra-operatively. The context in which this technology is applied (intra-operative or post-operative setting) is influenced by time after excision and surgical factors including cautery and the presence of patent blue dye (specifically Lymphazurin™, used for sentinel lymph node mapping). Optical endpoints of hemoglobin ([THb]), fat ([β-carotene]), and fibroglandular content via light scattering (<µ_s’>) measurements were quantified from diffuse reflectance spectra of lumpectomy and mastectomy specimens using a Monte Carlo model. A linear longitudinal mixed-effects model was used to fit the optical endpoints for the cautery and kinetics studies. Monte Carlo simulations and tissue mimicking phantoms were used for the patent blue dye experiments. [THb], [β-carotene], and <µ_s’> were affected by <3.3% error with <80 µM of patent blue dye. The percent change in [β-carotene], <µ_s’>, and [β-carotene]/<µ_s’> was <14% in 30 minutes, while percent change in [THb] was >40%. [β-carotene] and [β-carotene]/<µ_s’> were the only parameters not affected by cautery. This work demonstrates the importance of understanding the post-excision kinetics of ex-vivo tissue and the presence of cautery and patent blue dye for breast tumor margin assessment, to accurately interpret data and exploit underling sources of contrast.

Optimizing surgical margins in breast conservation

Adequate surgical margins in breast-conserving surgery for breast cancer have traditionally been viewed as a predictor of local recurrence rates. There is still no consensus on what constitutes an adequate surgical margin, however it is clear that there is a trade-off between widely clear margins and acceptable cosmesis. Preoperative approaches to plan extent of resection with appropriate margins (in the setting of surgery first as well as after neoadjuvant chemotherapy,) include mammography, US, and MRI. Improvements have been made in preoperative lesion localization strategies for surgery, as well as intraoperative specimen assessment, in order to ensure complete removal of imaging findings and facilitate margin clearance. Intraoperative strategies to accurately assess tumor and cavity margins include cavity shave techniques, as well as novel technologies for margin probes. Ablative techniques, including radiofrequency ablation as well as intraoperative radiation, may be used to extend tumor-free margins without resecting additional tissue. Oncoplastic techniques allow for wider resections while maintaining cosmesis and have acceptable local recurrence rates, however often involve surgery on the contralateral breast. As systemic therapy for breast cancer continues to improve, it is unclear what the importance of surgical margins on local control rates will be in the future.

Computerized decision support system for intraoperative analysis of margin status in breast conservation therapy

Background. Breast conservation therapy (BCT) is the standard treatment for breast cancer; however, 32–63% of procedures have a positive margin leading to secondary procedures. The standard of care to evaluate surgical margins is based on permanent section. Imprint cytology (IC) has been used to evaluate surgical samples but is limited by excessive cauterization thus requiring experienced cytopathologist for interpretation. An automated image screening process has been developed to detect cancerous cells from IC on cauterized margins. Methods. IC was prospectively performed on margins during lumpectomy operations for breast cancer in addition to permanent section on 127 patients. An 8-slide training subset and 8-slide testing subset were culled. H&E IC automated analysis, based on linear discriminant analysis, was compared to manual pathologist interpretation. Results. The most important descriptors, from highest to lowest performance, are nucleus color (23%), cytoplasm color (15%), shape (12%), grey intensity (9%), and local area (5%). There was 100% agreement between automated and manual interpretation of IC slides. Conclusion. Although limited by IC sampling variability, an automated system for accurate IC cancer cell identification system is demonstrated, with high correlation to manual analysis, even in the face of cauterization effects which supplement permanent section analysis.

Evaluation of resection margins in breast conservation therapy: the pathology perspective-past, present, and future

Tumor surgical resection margin status is important for any malignant lesion. When this occurs in conjunction with efforts to preserve or conserve the afflicted organ, these margins become extremely important. With the demonstration of no difference in overall survival between mastectomy versus lumpectomy and radiation for breast carcinoma, there is a definite trend toward smaller resections combined with radiation, constituting "breast-conserving therapy." Tumor-free margins are therefore key to the success of this treatment protocol. We discuss the various aspects of margin status in this setting, from a pathology perspective, incorporating the past and current practices with a brief glimpse of emerging future techniques.

Intraoperative imprint cytology and frozen section pathology for margin assessment in breast conservation surgery: a systematic review

BACKGROUND

Achieving negative surgical margins is critical to minimizing the risk of tumor recurrence in patients undergoing breast conservation surgery (BCS) for a breast malignancy. Our objective was to perform a systematic review comparing reexcision rates, sensitivity and specificity of the intraoperative use of the margin assessment techniques of imprint cytology (IC) and frozen section analysis (FSA), against permanent histopathologic section (PS).

METHODS

The databases PubMed, Web of Knowledge, Cochrane Library and CINAHL Plus were searched for literature published from 1997 to 2011. Original investigations of patients who underwent BCS for breast cancer that evaluated margin assessment with PS and/or IC or FSA were included. Of 182 titles identified, 41 patient cohorts from 37 articles met inclusion criteria: PS (n = 19), IC (n = 7) and FSA (n = 15). Studies were summarized qualitatively using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for cohort studies and the Strength of Recommendation Taxonomy (SORT) numerical scale for diagnostic studies.

RESULTS

The final reexcision rates after primary BCS were 35 % for PS, 11 % for IC (p = 0.001 vs. PS) and 10 % for FSA (p < 0.0001 vs. PS). For IC, reexcision rates decreased from 26 to 4 % (p = 0.18) and for FSA, reexcision rates decreased from 27 to 6 % (p < 0.0001). The pooled sensitivity of IC and FSA were 72 and 83 %. The pooled specificity of IC and FSA were 97 and 95 %. The average length of each technique was 13 min for IC and 27 min for FSA.

CONCLUSIONS

Patients who underwent BCS with intraoperative IC or FSA to assess negative surgical margins had significantly fewer secondary surgical procedures for excision of their breast malignancies.

[Intraoperative pathological rapid investigations in breast surgery]

In breast surgery intraoperative frozen sections for the diagnosis of malignancy has lost impact and has largely been replaced by preoperative core needle biopsies. Nevertheless, there is still need for immediate pathological investigation of native breast tissue during surgery due to three reasons: (1) macroscopic and microscopic evaluation of resection margins, (2) the histological analysis of sentinel lymph nodes in order to circumvent secondary axillary surgery and (3) the preparation of native tissue for tumor banking or measurement of biomarkers. Because histology provides only a facultative component of immediate pathological examination of breast specimens during surgery, the term frozen section does not seem to be appropriate anymore. Intraoperative evaluation of resection specimens by pathologists provides surgically relevant information immediately, guarantees standardized preparation and fixation of specimens and enables tissue banking of native tissue for assessment of biological markers.

Oncoplastic surgical techniques for personalized breast conserving surgery in breast cancer patient with small to moderate sized breast

Oncoplastic surgery has revolutionized the field of breast conserving surgery (BCS). The final aims of this technique are to obtain an adequate resection margin that will reduce the rate of local recurrence while simultaneously improving cosmetic outcomes. To obtain successful results after oncoplastic surgery, it is imperative that patients be risk-stratified based on risk factors associated with positive margins, that relevant imaging studies be reviewed, and that the confirmation of negative margins be confirmed during the initial operation. Patients who had small- to moderate-sized breasts are the most likely to be dissatisfied with the cosmetic outcome of surgery, even if the defect is small; therefore, oncoplastic surgery in this population is warranted. Reconstruction of the remaining breast tissue is divided into volume displacement and volume replacement techniques. The use of the various oncoplastic surgeries is based on tumor location and excised breast volume. If the excised volume is less than 100 g, the tumor location is used to determine which technique should be used, with the most commonly used technique being volume displacement. However, if the excised volume is greater than 100 g, the volume replacement method is generally used, and in cases where more than 150 g is excised, the latissimus dorsi myocutaneous flap may be used to obtain a pleasing cosmetic result. The local recurrence rate after oncoplastic surgery was lower than that of conventional BCS, as oncoplastic surgery reduced the rate of positive resection margins by resecting a wider section of glandular tissue. If the surgeon understands the advantages and disadvantages of oncoplastic surgery, and the multidisciplinary breast team is able to successfully collaborate, then the success rate of BCS with partial breast reconstruction can be increased while also yielding a cosmetically appealing outcome.

High-frequency ultrasound for intraoperative margin assessments in breast conservation surgery: a feasibility study

Background

In addition to breast imaging, ultrasound offers the potential for characterizing and distinguishing between benign and malignant breast tissues due to their different microstructures and material properties. The aim of this study was to determine if high-frequency ultrasound (20-80 MHz) can provide pathology sensitive measurements for the ex vivo detection of cancer in margins during breast conservation surgery.

Methods

Ultrasonic tests were performed on resected margins and other tissues obtained from 17 patients, resulting in 34 specimens that were classified into 15 pathology categories. Pulse-echo and through-transmission measurements were acquired from a total of 57 sites on the specimens using two single-element 50-MHz transducers. Ultrasonic attenuation and sound speed were obtained from time-domain waveforms. The waveforms were further processed with fast Fourier transforms to provide ultrasonic spectra and cepstra. The ultrasonic measurements and pathology types were analyzed for correlations. The specimens were additionally re-classified into five pathology types to determine specificity and sensitivity values.

Results

The density of peaks in the ultrasonic spectra, a measure of spectral structure, showed significantly higher values for carcinomas and precancerous pathologies such as atypical ductal hyperplasia than for normal tissue. The slopes of the cepstra for non-malignant pathologies displayed significantly greater values that differentiated them from the normal and malignant tissues. The attenuation coefficients were sensitive to fat necrosis, fibroadenoma, and invasive lobular carcinoma. Specificities and sensitivities for differentiating pathologies from normal tissue were 100% and 86% for lobular carcinomas, 100% and 74% for ductal carcinomas, 80% and 82% for benign pathologies, and 80% and 100% for fat necrosis and adenomas. Specificities and sensitivities were also determined for differentiating each pathology type from the other four using a multivariate analysis. The results yielded specificities and sensitivities of 85% and 86% for lobular carcinomas, 85% and 74% for ductal carcinomas, 100% and 61% for benign pathologies, 84% and 100% for fat necrosis and adenomas, and 98% and 80% for normal tissue.

Conclusions

Results from high-frequency ultrasonic measurements of human breast tissue specimens indicate that characteristics in the ultrasonic attenuation, spectra, and cepstra can be used to differentiate between normal, benign, and malignant breast pathologies.

Development of a spatially offset Raman spectroscopy probe for breast tumor surgical margin evaluation

The risk of local recurrence for breast cancers is strongly correlated with the presence of a tumor within 1 to 2 mm of the surgical margin on the excised specimen. Previous experimental and theoretical results suggest that spatially offset Raman spectroscopy (SORS) holds much promise for intraoperative margin analysis. Based on simulation predictions for signal-to-noise ratio differences among varying spatial offsets, a SORS probe with multiple source-detector offsets was designed and tested. It was then employed to acquire spectra from 35 frozen-thawed breast tissue samples in vitro. Spectra from each detector ring were averaged to create a composite spectrum with biochemical information covering the entire range from the tissue surface to ∼2 mm below the surface, and a probabilistic classification scheme was used to classify these composite spectra as "negative" or "positive" margins. This discrimination was performed with 95% sensitivity and 100% specificity, or with 100% positive predictive value and 94% negative predictive value.

Intraoperative Assessment of Breast Cancer Specimens Decreases Cost and Number of Reoperations

It is the aim of our study to determine if the assessment of intraoperative breast cancer margins leads to decreased incidence of repeat operations and decreased cost. We collected data prospectively from two hospitals in Austin, TX, University Medical Center at Brackenridge (UMCB) and Seton Northwest Hospital (SNW), over a 2-year period. Comparison was made to see if intraoperative margin assessment affected total surgical costs and need for reoperation. One hundred and seven cases met criteria for inclusion in the study (UMCB = 45, SNW = 62). Intraoperative margin assessment was used in zero cases at SNW (0%) and in 17 at UMCB (38%). Intraoperative assessment was used in 16 per cent of total cases. Sixty per cent of cases at SNW required subsequent return to the operating room. Twenty-four per cent of cases at UMCB required subsequent reoperation ( P < 0.05). The average number of surgical interventions required was 1 ± 0.3 with intraoperative assessment, 2 ± 0.6 without, ( P < 0.05). Total surgical costs were $15,341 ± $4,328 with intraoperative assessment and $22,013 ± $13,821 without ( P < 0.05). Use of intraoperative margin assessment for breast cancer operations leads to both a decrease in reoperations as well as a decrease in total operative costs.

Optical breast cancer margin assessment: an observational study of the effects of tissue heterogeneity on optical contrast

Introduction

Residual cancer following breast conserving surgery increases the risk of local recurrence and mortality. Margin assessment presents an unmet clinical need. Breast tissue is markedly heterogeneous, which makes distinguishing small foci of cancer within the spectrum of normal tissue potentially challenging. This is further complicated by the heterogeneity as a function of menopausal status. Optical spectroscopy can provide surgeons with intra-operative diagnostic tools. Here, we evaluate ex-vivo breast tissue and determine which sources of optical contrast have the potential to detect malignancy at the margins in women of differing breast composition.

Methods

Diffuse reflectance spectra were measured from 595 normal and 38 malignant sites from the margins of 104 partial mastectomy patients. All statistical tests were performed using Wilcoxon Rank-Sum tests. Normal and malignant sites were compared before stratifying the data by tissue type and depth and computing statistical differences. The frequencies of the normal tissue types were separated by menopausal status and compared to the corresponding optical properties.

Results

The mean reduced scattering coefficient, < μ_s' >, and concentration of total hemoglobin, [THb]), showed statistical differences between malignant (< μ_s' > : 8.96 cm^-1 ± 2.24_MAD, [THb]: 42.70 μM ± 29.31_MAD) compared to normal sites (< μ_s' > : 7.29 cm^-1 ± 2.15_MAD, [THb]: 32.09 μM ± 16.73_MAD) (P < 0.05). The sites stratified according to normal tissue type (fibro-glandular (FG), fibro-adipose (FA), and adipose (A)) or disease type (invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS)) showed that FG exhibited increased < μ_s' > and A showed increased [β-carotene] within normal tissues. Scattering differentiated between most malignant sites, DCIS (9.46 cm^-1 ± 1.06_MAD) and IDC (8.00 cm^-1 ± 1.81_MAD), versus A (6.50 cm^-1 ± 1.95_MAD). [β-carotene] showed marginal differences between DCIS (19.00 μM ± 6.93_MAD, and FG (15.30 μM ± 5.64_MAD). [THb] exhibited statistical differences between positive sites (92.57 μM ± 18.46_MAD) and FG (34.12 μM ± 22.77_MAD), FA (28.63 μM ± 14.19_MAD), and A (30.36 μM ± 14.86_MAD). The diagnostic ability of the optical parameters was affected by distance of tumor from the margin as well as menopausal status. Due to decreased fibrous content and increased adipose content, normal sites in post-menopausal patients exhibited lower < μ_s' >, but higher [β-carotene] than pre-menopausal patients.

Conclusions

The data indicate that the ability of an optical parameter to differentiate benign from malignant breast tissues may be dictated by patient demographics. Scattering differentiated between malignant and adipose sites and would be most effective in post-menopausal women. [β-carotene] or [THb] may be more applicable in pre-menopausal women to differentiate malignant from fibrous sites. Patient demographics are therefore an important component to incorporate into optical characterization of breast specimens.

A low-cost, portable, and quantitative spectral imaging system for application to biological tissues

The ability of diffuse reflectance spectroscopy to extract quantitative biological composition of tissues has been used to discern tissue types in both pre-clinical and clinical cancer studies. Typically, diffuse reflectance spectroscopy systems are designed for single-point measurements. Clinically, an imaging system would provide valuable spatial information on tissue composition. While it is feasible to build a multiplexed fiber-optic probe based spectral imaging system, these systems suffer from drawbacks with respect to cost and size. To address these we developed a compact and low cost system using a broadband light source with an 8-slot filter wheel for illumination and silicon photodiodes for detection. The spectral imaging system was tested on a set of tissue mimicking liquid phantoms which yielded an optical property extraction accuracy of 6.40 +/- 7.78% for the absorption coefficient (micro(a)) and 11.37 +/- 19.62% for the wavelength-averaged reduced scattering coefficient (micro(s)').

Performance metrics of an optical spectral imaging system for intra-operative assessment of breast tumor margins

As many as 20-70% of patients undergoing breast conserving surgery require repeat surgeries due to a close or positive surgical margin diagnosed post-operatively [1]. Currently there are no widely accepted tools for intra-operative margin assessment which is a significant unmet clinical need. Our group has developed a first-generation optical visible spectral imaging platform to image the molecular composition of breast tumor margins and has tested it clinically in 48 patients in a previously published study [2]. The goal of this paper is to report on the performance metrics of the system and compare it to clinical criteria for intra-operative tumor margin assessment. The system was found to have an average signal to noise ratio (SNR) >100 and <15% error in the extraction of optical properties indicating that there is sufficient SNR to leverage the differences in optical properties between negative and close/positive margins. The probe had a sensing depth of 0.5-2.2 mm over the wavelength range of 450-600 nm which is consistent with the pathologic criterion for clear margins of 0-2 mm. There was <1% cross-talk between adjacent channels of the multi-channel probe which shows that multiple sites can be measured simultaneously with negligible cross-talk between adjacent sites. Lastly, the system and measurement procedure were found to be reproducible when evaluated with repeated measures, with a low coefficient of variation (<0.11). The only aspect of the system not optimized for intra-operative use was the imaging time. The manuscript includes a discussion of how the speed of the system can be improved to work within the time constraints of an intra-operative setting.

Optical assessment of tumor resection margins in the breast

Breast conserving surgery, in which the breast tumor and surrounding normal tissue are removed, is the primary mode of treatment for invasive and in situ carcinomas of the breast, conditions that affect nearly 200,000 women annually. Of these nearly 200,000 patients who undergo this surgical procedure, between 20-70% of them may undergo additional surgeries to remove tumor that was left behind in the first surgery, due to the lack of intra-operative tools which can detect whether the boundaries of the excised specimens are free from residual cancer. Optical techniques have many attractive attributes which may make them useful tools for intra-operative assessment of breast tumor resection margins. In this manuscript, we discuss clinical design criteria for intra-operative breast tumor margin assessment, and review optical techniques appied to this problem. In addition, we report on the development and clinical testing of quantitative diffuse reflectance imaging (Q-DRI) as a potential solution to this clinical need. Q-DRI is a spectral imaging tool which has been applied to 56 resection margins in 48 patients at Duke University Medical Center. Clear sources of contrast between cancerous and cancer-free resection margins were identified with the device, and resulted in an overall accuracy of 75% in detecting positive margins.

Rapid noninvasive optical imaging of tissue composition in breast tumor margins

BACKGROUND

In women undergoing breast conserving surgery (BCS), up to 60% can require re-excision. Our objective is to develop an optically based technology which can differentiate benign from malignant breast tissues intraoperatively through differences in tissue composition factors.

METHODS

A prospective study of optical imaging of BCS margins is being performed. Optical images are transformed into tissue composition maps with parameters of total hemoglobin concentration, b-carotene concentration and scattering. The predicted outcome is then compared to the margin-level pathology.

RESULTS

Fifty-five margins from 48 patients have undergone assessment. Within 34 specimens with pathologically confirmed positive margins, the ratio map of b-carotene/scattering showed the most significant difference reflecting a decrease in adipose and an increase in cell density within malignant margins (p=.002). These differences were notable in both in-situ and invasive disease.

CONCLUSIONS

We present a novel optical spectral imaging device that provides a rapid, non-destructive assay of the tissue composition of breast tumor margins.