New technologies in breast cancer surgery

Magnetic resonance imaging system for intraoperative margin assessment for DCIS and invasive breast cancer using the ClearSight™ system in breast-conserving surgery-Results from a postmarketing study

BACKGROUND AND OBJECTIVES

Breast-conserving surgery (BCS) is followed by reoperations in approximately 25%. Reoperations lead to an increased risk of infection and wound healing problems as well as a worse cosmetic outcome. Several technical approaches for an intraoperative margin assessment to decrease the reoperation rate are under evaluation, some of them are still experimental.

METHODS

A prospective single-arm post-marketing study with 60 patients undergoing BCS for ductal carcinoma in situ (DCIS) and invasive breast cancer was conducted. The specimen was intraoperatively examined by the ClearSight™ system, a mobile magnetic resonance imaging system that is based on a diffusion-weighted imaging protocol. However, the results were blinded to the surgeon.

RESULTS

The ClearSight™ system was performed for both ductal and lobular breast cancer and DCIS, with a sensitivity of 0.80 (95% confidence interval [CI]: 0.44-0.96) and a specificity of 0.84 (95% CI 0.72-0.92), with an overall diagnostic accuracy of 80%.

CONCLUSION

Had the ClearSight™ been known to the surgeon intraoperatively, the reoperation rate would have been reduced by 83% for invasive carcinoma, from 10% to 2%, and 50% for DCIS, from 30% to 15% reoperations. A trial designed to examine the impact on reoperation rates is currently ongoing.

Concept for using magnetic particle imaging for intraoperative margin analysis in breast-conserving surgery

Breast-conserving surgery (BCS) is a commonly utilized treatment for early stage breast cancers but has relatively high reexcision rates due to post-surgical identification of positive margins. A fast, specific, sensitive, easy-to-use tool for assessing margins intraoperatively could reduce the need for additional surgeries, and while many techniques have been explored, the clinical need is still unmet. We assess the potential of Magnetic Particle Imaging (MPI) for intraoperative margin assessment in BCS, using a passively or actively tumor-targeted iron oxide agent and two hardware devices: a hand-held Magnetic Particle detector for identifying residual tumor in the breast, and a small-bore MPI scanner for quickly imaging the tumor distribution in the excised specimen. Here, we present both hardware systems and demonstrate proof-of-concept detection and imaging of clinically relevant phantoms.

Effect of LigaSure™, Monopolar Cautery, and Bipolar Cautery on Surgical Margins in Breast-Conserving Surgery

Background

We compared the differences in thermal damage at the surgical margin between monopolar cautery, bipolar cautery, and LigaSure™ in breast cancer lumpectomy specimens and assessed the effect of these techniques on the evaluation of the surgical margins.

Methods

30 patients scheduled for breast-conserving surgery for breast cancer were included in this study. During lumpectomy, each of the superior, inferior, lateral, and medial borders of the tumour was excised using one of the following: a scalpel, monopolar cautery, bipolar cautery, and LigaSure technology. The surgical margins of frozen and paraffin-embedded tissue sections of the lumpectomy specimen were evaluated. Thermal damage was defined as the maximum depth of thermal damage (in mm) from the surgical margin, and the level was categorized as none, low (≤1 mm), or high (>1 mm).

Results

There was no statistically significant difference between monopolar cautery, bipolar cautery, and LigaSure in terms of thermal damage. There was no thermal damage at the surgical margin in tissues dissected by scalpel.

Conclusion

Thermal damage due to the excision method may cause false-negative and false-positive results in the surgical margin evaluation of lumpectomy specimens. More research is needed on the effects of different energy modalities on surgical margin evaluation in breast-conserving surgery.

Costs and effects of intra-operative fluorescence molecular imaging - A model-based, early assessment

Introduction

Successful breast conserving cancer surgeries come along with tumor free resection margins and account for cosmetic outcome. Positive margins increase the likelihood of tumor recurrence. Intra-operative fluorescence molecular imaging (IFMI) aims to focus surgery on malignant tissue thus substantially lowering the presence of positive margins as compared with standard techniques of breast conservation (ST). A goal of this paper is to assess the incremental number of surgeries and costs of IFMI vs. ST.

Methods

We developed a decision analytical model and applied it for an early evaluation approach. Given uncertainty we considered that IFMI might reduce the proportion of positive margins found by ST from all to none and this proportion is assumed to be reduced to 10% for the base case. Inputs included data from the literature and a range of effect estimates. For the costs of IFMI, respective cost components were added to those of ST.

Results

The base case reduction lowered number of surgeries (mean [95% confidence interval]) by 0.22 [0.15; 0.30] and changed costs (mean [95% confidence interval]) by €-663 [€-1,584; €50]. A tornado diagram identified the Diagnosis Related Group (DRG) costs, the proportion of positive margins of ST, the staff time saving factor and the duration of frozen section analysis (FSA) as important determinants of this cost.

Conclusions

These early results indicate that IFMI may be more effective than ST and through the reduction of positive margins it is possible to save follow-up surgeries–indicating further health risk–and to save costs through this margin reduction and the avoidance of FSA.

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.

Imaging methods for the local lymphatic system of the axilla in early breast cancer in patients qualified for sentinel lymph node biopsy

Breast cancer is the most common malignancy in women in well-developed countries. Despite a constant increase in its incidence, the percentage of patients diagnosed with the disease in the non-invasive stage is also rising. This allows more frequently for the use of breast-preserving surgical techniques, involving the breast and the regional lymphatic system.

According to current guidelines of expert panels and research societies, the recommended method of identifying the sentinel lymph node is the use of an isotope marker with a dye (a combined isotope and dye method). Cooperation with a nuclear medicine unit is essential (performing a preoperative lymphoscintigraphic scan to identify the lymphatic drainage basin and sentinel lymph node). In the case of smaller centers treating breast cancer, it can be associated with a number of difficulties, including organizational ones, and also increasing general treatment costs.

A possible solution to these problems is to use alternative techniques of visualizing the sentinel lymph node, which do not require a radiotracer. In this paper we discuss the currently available methods of mapping the lymphatic system of the axillary region in patients with early breast cancer. The review is limited to reporting on methods of proven (based on clinical research) high diagnostic value.

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.

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%.