Can Low-cost Indo Cyanine Green Florescence Technique for Sentinel Lymph Node Biopsy Replace Dual Dye (Radio-colloid and Blue Dye) Technique in Early Breast Cancer: A Prospective Two-arm Comparative Study

Indocyanine green fluorescence versus blue dye, technetium-99M, and the dual-marker combination of technetium-99M + blue dye for sentinel lymph node detection in early breast cancer-meta-analysis including consistency analysis

BACKGROUND

Axillary sentinel lymph node biopsies are standard of care in patients with breast cancer and no clinically apparent metastases. Traditionally, technetium-99m, blue dye, or both have been used to identify sentinel lymph nodes. However, blue dyes miss up to 40% of sentinel lymph nodes, while technetium-99m use is complex, costly, and exposes patients to radiation. Over the past decade, studies have consistently found the biologically inert fluorescent indocyanine green to be 95% to 100% sensitive in detecting breast cancer sentinel lymph nodes, yet indocyanine green remains infrequently used.

METHODS

We conducted an extensive meta-analysis comparing indocyanine green against blue dye, technetium-99m, and the dual-marker combination of technetium-99m + BD. Unlike prior meta-analyses that only assessed either per-case or per-node sentinel lymph node detection, we analyzed the following 5 metrics: per-case and per-node sentinel lymph node detection and metastasis-positive sentinel lymph node sensitivity, and mean number of sentinel lymph nodes/case. We further examined the consistency and magnitude of between-study superiority and statistically significant within-study superiority of each marker against others.

RESULTS

For every metric and analysis approach, indocyanine green was clearly superior to blue dye and at least non-inferior, if not superior, to technetium-99m and technetium-99m + blue dye. Assessing the consistency of superiority by at least 2.0%, indocyanine green was superior to blue dye 73 times versus 1, to technetium-99m 42 times versus 9, and to technetium-99m + blue dye 6 times versus 0. Within-study statistically significant differences favored indocyanine green over blue dye 29 times versus 0 and over technetium-99m 11 times versus 2.

DISCUSSION

For sentinel lymph node detection in patients with breast cancer with no clinically apparent metastases, indocyanine green is clearly and consistently superior to blue dye and either non-inferior or superior to technetium-99m and technetium-99m + blue dye.

Fluorescence imaging for real-time detection of breast cancer tumors using IV injection of indocyanine green with non-conventional imaging: a systematic review of preclinical and clinical studies of perioperative imaging technologies

BACKGROUND

This review summarizes the available data on the effectiveness of indocyanine green fluorescence imaging (ICG-FI) for real-time detection of breast cancer (BC) tumors with perioperative imaging technologies.

METHODS

PubMed and Scopus databases were exhaustively searched for publications on the use of the real-time ICG-FI evaluation of BC tumors with non-conventional breast imaging technologies.

RESULTS

Twenty-three studies were included in this review. ICG-FI has been used for BC tumor identification in 12 orthotopic animal tumor experiences, 4 studies on animal assessment, and for 7 human clinical applications. The BC tumor-to-background ratio (TBR) was 1.1-8.5 in orthotopic tumor models and 1.4-3.9 in animal experiences. The detection of primary human BC tumors varied from 40% to 100%. The mean TBR reported for human BC varied from 2.1 to 3.7. In two studies evaluating BC surgical margins, good sensitivity (93.3% and 100%) and specificity (60% and 96%) have been reported, with a negative predictive value of ICG-FI to predict margin involvement intraoperatively of 100% in one study.

CONCLUSIONS

The use of ICG-FI as a guiding tool for the real-time identification of BC tumors and for the assessment of tumor boundaries is promising. There is great variability between the studies with regard to timing and dose. Further evidence is needed to assess whether ICG-guided BC surgery may be implemented as a standard of care.

Determining Accurate Dye Combinations for Sentinel Lymph Node Detection: A Systematic Review

Background

Lymphatic dyes are commonly used to map the drainage path from tumor to lymphatics, which are biopsied to determine if spread has occurred. A blue dye in combination with technetium-99 is considered the gold standard for mapping, although many other dyes and dye combinations are used. Not all of these substances have the same detection efficacy.

Methods

A systematic review of PubMed, SCOPUS, Web of Science, and Medline was performed. The predefined search terms were (indocyanine green OR isosulfan blue OR lymphazurin OR patent blue OR methylene blue OR fluorescein OR technetium-99) AND combination AND dye AND (sentinel lymph node biopsy OR lymphedema OR lymphatics OR lymph OR microsurgery OR cancer OR tumor OR melanoma OR carcinoma OR sarcoma).

Results

The initial search returned 4267 articles. From these studies, 37 were selected as candidates that met inclusion criteria. After a full-text review, 34 studies were selected for inclusion. Eighty-nine methods of sentinel lymph node (SLN) detection were trialed using 22 unique dyes, dye combinations, or other tracers. In total, 12,157 SLNs of 12,801 SLNs were identified. Dye accuracy ranged from 100% to 69.8% detection. Five dye combinations had 100% accuracy. Dye combinations were more accurate than single dyes.

Conclusions

Combining lymphatic dyes improves SLN detection results. Replacing technetium-99 with ICG may allow for increased access to SLN procedures with comparable results. The ideal SLN tracer is a low-cost molecule with a high affinity for lymphatic vessels due to size and chemical composition, visualization without specialized equipment, and no adverse effects.

Evaluation of learning curve with Indocyanine Green (IcG) versus blue dye for sentinel lymph node biopsy in breast cancer

BACKGROUND

Indocyanine green (IcG) is an alternative to isosulfan blue (IB) for sentinel lymph node (SLN) mapping in breast cancer (BC). IcG carries improved cost and safety, but oncologic data upon implementation in practice is limited. We evaluated the learning curve defined as oncologic yield and operative (OR) time for IcG in SLN mapping in BC.

METHODS

Retrospective review of patients >18 years with cTis-2 cN0 BC undergoing surgery first with SLN biopsy using IB or IcG. Analysis compared IB versus IcG across three time cohorts.

RESULTS

Of 278 patients, 77 received IB and 201 received IcG. OR time was longer for IcG (p ​= ​0.022). There was no difference in oncologic yield between groups (p ​= ​0.35, p ​= ​0.61).

CONCLUSIONS

Surgeons may be able to safely transition from IB to IcG for patients with early-stage breast cancer undergoing surgery first. Individuals should track their own data to confirm safety of the technique.

An Updated Review on the Emerging Role of Indocyanine Green (ICG) as a Sentinel Lymph Node Tracer in Breast Cancer

Sentinel lymph node biopsy (SLNB) has become the standard of care for clinically node-negative breast cancer and has recently been shown by clinical trials to be also feasible for clinically node-positive patients treated with primary systemic therapy. The dual technique using both radioisotope (RI) and blue dye (BD) as tracers for the identification of sentinel lymph nodes is considered the gold standard. However, allergic reactions to blue dye as well as logistics issues related to the use of radioactive agents, have led to research on new sentinel lymph node (SLN) tracers and to the development and introduction of novel techniques in the clinical practice. Indocyanine green (ICG) is a water-soluble dye with fluorescent properties in the near-infrared (NIR) spectrum. ICG has been shown to be safe and effective as a tracer during SLNB for breast cancer and accumulating evidence suggests that ICG is superior to BD and at least comparable to RI alone and to RI combined with BD. Thus, ICG was recently proposed as a reliable SLN tracer in some breast cancer clinical practice guidelines. Nevertheless, there is lack of consensus regarding the optimal role of ICG for SLN mapping. Specifically, it is yet to be determined whether ICG should be used in addition to BD and/or RI, or if ICG could potentially replace these long-established traditional SLN tracers. This article is an updated overview of somerecent studies that compared ICG with BD and/or RI regarding their accuracy and effectiveness during SLNB for breast cancer.

New techniques versus standard mapping for sentinel lymph node biopsy in breast cancer: a systematic review and meta-analysis

New tracers for sentinel lymph node biopsy (SLNB), as indocyanine green (ICG), superparamagnetic iron oxide (SPIO) and micro bubbles, have been recently introduced in clinical practice showing promising but variable results. We reviewed the available evidence comparing these new techniques with the standard tracers to evaluate their safety. To identify all available studies, a systematic search was performed in all electronic databases. Data regarding sample size, mean number of SLN harvested for patient, number of metastatic SLN and SLN identification rate of all studies were extracted. No significant differences were found in terms of SLNs identification rates between SPIO, RI and BD but with a higher identification rate with the use of ICG. No significant differences were also found for the number of metastatic lymph nodes identified between SPIO, RI and BD and the mean number of SLNs identified between SPIO and ICG versus conventional tracers. A statistically significant differences in favor of ICG was reported for the comparison between ICG and conventional tracers for the number of metastatic lymph nodes identified. Our meta-analysis demonstrates that the use of both ICG and SPIO for the pre-operative mapping of sentinel lymph nodes in breast cancer treatment is adequately effective.

Indocyanine Green Is a Safe and Effective Alternative to Radioisotope in Breast Cancer Sentinel Lymph Node Biopsy regardless of Patient Body Mass Index

INTRODUCTION

A recent meta-analysis [Lancet Oncol. 2010;11:908-909] has confirmed high sensitivity of indocyanine green (ICG) fluorescence mapping for sentinel node detection in early breast cancer. Concerns have previously been raised regarding the efficacy in patients with high body mass index (BMI).

MATERIALS AND METHODS

All consecutive patients undergoing sentinel lymph node biopsies (SLNBs) for early breast cancer in NHS Tayside were included in a prospective audit of surgical and pathology findings. All patients included in the study received dual injection of patent blue dye and ICG. Approval was obtained from the local Caldicott guardian for collection and use of personal data.

RESULTS

Of 239 cases, all were female patients of mean age 62 years (range 27-93). In 4.2% (10/239) of cases, neither blue dye nor ICG was present in the axilla. Of the remaining 229 SLNB cases in this series, surgeons documented retrieval of 451 nodes, with a mean surgical nodal count per case of 1.97 (range 1-5) and pathological nodal count of 2.15 (range 0-7). Eighty three cases were performed in patients with BMI 30-39.9 and 21 cases with BMI ≥40, with nodal detection rates of 96.4% (80/83) and 95.2% (20/21), respectively, in these groups of patients. Twenty percent (48/229) of cases had nodal metastases on histopathology.

CONCLUSIONS

This is a large single-center study which demonstrates the safety and accuracy of the combined ICG and blue dye technique for SLNB in breast cancer. This is represented by nodal detection rates and node positivity rates which are comparable to previous multicenter studies of standard SLNB regardless of BMI.

Comparing single or dual tracing modality on sentinel lymph node biopsy from patients who plan to omitting axillary lymph node dissection referring to the criteria of Z0011 trial: a retrospective study

Axillary lymph node dissection (ALND) can be omitted in the part of the breast-conserving patients with positive sentinel lymph nodes (SLNs) since Z0011 trial has presented. Nevertheless, to date, no studies revealed the influence of different tracing modalities (single tracer versus dual tracers) for sentinel lymph node biopsy (SLNB) on axillary management referring to Z0011 trial criteria. This study aimed to assess whether different tracing modalities of SLNB have impact on axillary management referring to Z0011 trial criteria. The clinical data of breast-conserving patients who underwent SLNB guided by combination of methylene blue (MB) and indocyanine green(ICG) were retrospectively analyzed in our center. The numbers of metastatic (positive) SLNs guided by the single tracer and the dual tracer were compared by self-control study. 127 patients with 1-2 metastatic SLNs dyed by MB [(recorded as MB(+))]were retrieved from our database between 2016 and 2020. In these cases, 53 patients contained 86 SLNs, which were ICG staining but MB negative staining (recorded as ICG(+)/MB(-)). In addition, 16 patients contained 20 metastatic SLNs with ICG(+)/MB(-). There were six patients finally excluded patients (6/127, 4.7%) who initially met the criteria of Z0011 trial, because the further detection of ICG(+)/MB(-) SLNs led the total numbers of positive SLNs over two. The difference was statistically significant. Single tracing modality may underestimate the positive SLN numbers compared to dual tracing modality. Different tracing modalities of SLNB will significantly affect Axillary management referring to Z0011 trial criteria.

A Prospective Self-Controlled Study of Indocyanine Green, Radioisotope, and Methylene Blue for Combined Imaging of Axillary Sentinel Lymph Nodes in Breast Cancer

Purpose

This self-controlled study aimed to clarify whether indocyanine green (ICG) could be an alternative tracer in the absence of radioisotope (RI) for combined imaging of axillary sentinel lymph node (SLN) in breast cancer.

Methods

Primary breast cancer, clinically axillary node-negative patients (n = 182) were prospectively enrolled from March 2015 to November 2020. ICG, methylene blue (MB), and RI were used to perform axillary sentinel lymph node biopsy (SLNB). The main observation index was the positivity of ICG + MB vs. RI + MB in axillary SLNB; the secondary observation indicators were the axillary SLN detection rate, mean number of axillary SLNs detected, mean number of metastatic axillary SLNs detected, and safety.

Results

All 182 patients had axillary SLNs; a total of 925 axillary SLNs were detected. Pathological examination confirmed metastatic axillary SLN in 42 patients (total of 79 metastatic SLNs). Positivity, detection rate of SLNs, detection rate of metastatic SLNs, and the number of metastatic SLNs detected were comparable with RI+MB and ICG+MB (p > 0.05). The mean number of axillary SLNs detected was significantly higher with ICG+MB than with RI+MB (4.99 ± 2.42 vs. 4.02 ± 2.33, p < 0.001). No tracer-related adverse events occurred.

Conclusions

ICG appears to be a safe and effective axillary SLN tracer, and a feasible alternative to RI in combined imaging for axillary SLN of breast cancer.

Techniques for sentinel node biopsy in breast cancer

INTRODUCTION

Sentinel node biopsy (SNB) is the standard of care in women with breast cancer (BC) and clinically non suspicious axillary lymph nodes (LNs), due to its high negative predictive value (NPV) in the assessment of nodal status. SNB has significantly reduced complications related to the axillary lymph node dissection, such as lymphedema and upper limb dysfunction.

EVIDENCE ACQUISITION

The gold standard technique for SNB is the blue dye (BD) and technetium labelled nanocolloid (Tc-99m) double technique. However, nuclear medicine is not available in all Institutions and several new tracers and devices have been proposed, such as indocyanine green (ICG) and superparamagnetic iron oxides (SPIO). All these techniques show an accuracy and detection rate not inferior to that of the standard technique, with different specific pros and cons. The choice of how to perform a SNB primarily depends on the surgeon's confidence with the procedure, the availability of nuclear medicine and the economic resources of the Institutions. In this setting, new tracers, hybrid tracers and imaging techniques are being evaluated in order to improve the detection rate of sentinel lymph nodes (SNs) and minimize the number of unnecessary axillary surgeries through an accurate preoperative assessment of nodal status and to guide new minimally invasive diagnostic procedures of SNs. In particular, the contrast-enhanced ultrasound (CEUS) is an active field of research but cannot be recommended for clinical use at this time.

EVIDENCE SYNTHESIS

The ICG fluorescence technique was superior in terms of DR, as well as having the lowest FNR. The DR descending order was SPIO, Tc, dual modality (Tc/BD), CEUS and BD.

CONCLUSIONS

This paper is a narrative review of the most common SNB techniques in BC with a focus on recent innovations.

Meta-analysis Comparing Fluorescence Imaging with Radioisotope and Blue Dye-Guided Sentinel Node Identification for Breast Cancer Surgery

INTRODUCTION

Conventional methods for axillary sentinel lymph node biopsy (SLNB) are fraught with complications such as allergic reactions, skin tattooing, radiation, and limitations on infrastructure. A novel technique has been developed for lymphatic mapping utilizing fluorescence imaging. This meta-analysis aims to compare the gold standard blue dye and radioisotope (BD-RI) technique with fluorescence-guided SLNB using indocyanine green (ICG).

METHODS

This study was registered with PROSPERO (CRD42019129224). The MEDLINE, EMBASE, Scopus, and Web of Science databases were searched using the Medical Subject Heading (MESH) terms 'Surgery' AND 'Lymph node' AND 'Near infrared fluorescence' AND 'Indocyanine green'. Studies containing raw data on the sentinel node identification rate in breast cancer surgery were included. A heterogeneity test (using Cochran's Q) determined the use of fixed- or random-effects models for pooled odds ratios (OR).

RESULTS

Overall, 1748 studies were screened, of which 10 met the inclusion criteria for meta-analysis. ICG was equivalent to radioisotope (RI) at sentinel node identification (OR 2.58, 95% confidence interval [CI] 0.35-19.08, p < 0.05) but superior to blue dye (BD) (OR 9.07, 95% CI 6.73-12.23, p < 0.05). Furthermore, ICG was superior to the gold standard BD-RI technique (OR 4.22, 95% CI 2.17-8.20, p < 0.001).

CONCLUSION

Fluorescence imaging for axillary sentinel node identification with ICG is equivalent to the single technique using RI, and superior to the dual technique (RI-BD) and single technique with BD. Hospitals using RI and/or BD could consider changing their practice to ICG given the comparable efficacy and improved safety profile, as well as the lesser burden on hospital infrastructure.

Comparative study of two contrast agents for intraoperative identification of sentinel lymph nodes in patients with early breast cancer

Background

The use of contrast-enhanced ultrasound (CEUS) to locate sentinel lymph nodes (SLNs) in breast cancer has been studied more and more in recent years. This prospective study aimed to compare periareolar injection of two different contrast agents, SonoVue^® (SNV) and Sonazoid^® (SNZ), followed by CEUS to identify SLNs in breast cancer patients with clinically negative nodes.

Methods

A total of 205 patients with T1-2N0M0 breast cancer were divided into the SNV group and SNZ group. All were administered a periareolar injection of SNV or SNZ and underwent US to identify contrast-enhanced SLNs. Each contrast-enhanced SLN underwent a biopsy with blue dye and examined again by CEUS in vitro.

Results

In all cases, contrast-enhanced lymphatic vessels were clearly visualized using US soon after the periareolar injection of SNZ, and the SLNs were easily identified. The SLN identification rates were 75.27% (210/279) for SNV and 93.58% (102/109) for SNZ. Although the accuracy of detecting SLN metastasis was slightly different between the two groups, there was no statistically significant difference between those groups (P=0.615). Moreover, it was possible to identify SLNs in vitro in the SNZ group, and these could be compared with the lymph nodes (LNs) located using SNZ during the preoperative stage and with blue dye during the procedure. This helped in determining the resection requirements.

Conclusions

When comparing the subdermal use of SNV and SNZ, no significant differences in the number of detected SLNs and the diagnosis of metastatic LNs were observed. Because SLNs can be detected for a longer time in living tissues with SNZ, this contrast agent may provide more intraoperative information for complete resection of all preoperative localization of SLN.