A Novel Indocyanine Green Fluorescence-Guided Video-Assisted Technique for Sentinel Node Biopsy in Breast Cancer

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.

Clinical use of Indocyanine green fluorescence method for sentinel lymph node biopsy in breast cancer in France in 2021

INTRODUCTION

Indocyanine green (ICG) for axillary sentinel lymph node (SLN) detection in early breast cancer is at least equivalent to radioisotopic and/or colorimetric techniques. This procedure has not yet been recommended by learned societies in France. Following the recent drug approval of Infracyanin ® in this indication, we wished to study the use of ICG in France.

METHODS

We conducted a web-based survey among members of multiple French breast cancer societies throughout November 2021. The survey assessed the profile of the respondent, the use or not of ICG for the detection of SLN in breast cancer, the technique used and the opinion of non-users and their expectations on the subject.

RESULTS

Seventy-five surgeons participated. More than a third (37 %) have been using ICG for the detection of SLN in breast cancer for 2 to 3 years. Technique was highly variable. According to 82.1 % of the respondents, less than 20 procedures are necessary to master the use of ICG. The main advantage reported for this method is the reduction of organizational constraints. The obstacles to the use of the ICG are the near infra-red camera equipment, but also the lack of validation by the French guidelines. Among non-users, 83 % would like to develop this technique in their center and 72.3 % are interested in training on this subject.

CONCLUSION

This work highlights the need for French learned societies to take a stand on this issue but also the need to carry out studies on the technical aspects in order to standardise practices.

Evaluation of the efficacy of using indocyanine green associated with fluorescence in sentinel lymph node biopsy

INTRODUCTION

Sentinel lymph node biopsy is the technique recommended for the axillary staging of patients with breast cancer in the initial stages without clinical axillary involvement. Three techniques are widely used globally to detect sentinel lymph nodes: patent blue, the radiopharmaceutical technetium 99 with gamma probe, and the combination of these two.

OBJECTIVES

To evaluate the sentinel lymph node detection rate with an innovative technique: indocyanine green (ICG) associated with fluorescence in breast cancer patients, and compare it with patent blue and a combination of patent blue and indocyanine green.

METHODS

99 patients were sequentially (not randomly) allocated into 3 arms with 33 patients submitted to sentinel lymph node techniques. One arm underwent patent blue dying, the other indocyanine green, and the third received a combination of both. The detection rates between arms were compared.

RESULTS

The detection rate in identifying the sentinel lymph node was 78.8% with patent blue, 93.9% with indocyanine green, and 100% with the combination. Indocyanine green identified two sentinel nodes in 48.5% of patients; the other groups more commonly had only one node identified. The mean time to sentinel lymph node identification was 20.6 ± 10.7 SD (standard deviation) minutes among patients submitted to the patent blue dye, 8.6 ± 6.6 minutes in the indocyanine green arm, and 10 ± 8.9 minutes in the combined group (P<0.001; Student's test). The mean surgery time was 69.4 ± 16.9; 55.1 ± 13.9; and 69.4 ± 19.3 minutes respectively (P<0.001; Student's test).

CONCLUSIONS

The sentinel lymph node detection rate by fluorescence using indocyanine green was 93.9%, considered adequate. The rates using patent blue, indocyanine green, and patent blue plus indocyanine green (combined) were significantly different, and the indocyanine green alone is also acceptable, since it has a good performance in sentinel lymph node identification and it can avoid tattooing, with a 100% sentinel lymph node detection rate when combined with patent blue.

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.

Clinical translational barriers against nanoparticle-based imaging agents

Nanoparticle based imaging agents (NIAs) have been intensively explored in bench studies. Unfortunately, only a few cases have made their ways to clinical translation. In this review, clinical trials of NIAs were investigated for understanding possible barriers behind that. First, the complexity of multifunctional NIAs is considered a main barrier because it brings uncertainty to batch-to-batch fabrication, and results in sophisticated in vivo behaviors. Second, inadequate biosafety studies slow down the translational work. Third, NIA uptake at disease sites is highly heterogeneous, and often exhibits poor targeting efficiency. Focusing on the aforementioned problems, key design parameters were analyzed including NIAs' size, composition, surface characteristics, dosage, administration route, toxicity, whole-body distribution and clearance in clinical trials. Possible strategies were suggested to overcome these barriers. Besides, regulatory guidelines as well as scale-up and reproducibility during manufacturing process were covered as they are also key factors to consider during clinical translation of NIAs.

Discovery of novel phenaleno isoquinolinium-based fluorescence imaging agents for sentinel lymph node mapping

Fluorescence imaging agents have recently received huge attention due to their important role in disease diagnostics. However, the intrinsic problems of these probes, such as complex synthetic routes and high molecular weight, remain challenging. Here, we developed novel phenaleno isoquinolinium-based fluorescent agents, Medical Fluorophores 37-41 (MF37-41), applicable to the quantitative and sensitive detection of sentinel lymph nodes (SLNs). These imaging agents showed no adverse effects on the proliferation of immune and normal cells and did not induce in vivo toxicity. In vivo fluorescence lifetime imaging demonstrated the accumulation of phenaleno isoquinolinium salts in the SLNs of nude mice within 15 min postinjection, consistent with our biodistribution findings. These results suggest that phenaleno isoquinolinium salts are feasible fluorescence imaging agents that can be used as potential lymphatic tracers.

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.

Novel quinoline-based fluorescent bioimaging probe, KSNP117, for sentinel lymph node mapping

Fluorescent imaging agents with biocompatibility and high sensitivity are urgently required for the accurate detection of sentinel lymph nodes (SLNs). Herein, we report the design of a novel quinoline-based fluorescent probe, designated KSNP117, which can be applied as a biomedical imaging agent in the sensitive and quantitative detection of SLNs. KSNP117 exerted no adverse effects on the proliferation of ovary and immune cells and also showed excellent serum stability with photo-brightening effects. In vivo fluorescent imaging revealed the accumulation of KSNP117 in the SLNs of nude mice within 10 min post injection, without in vivo toxicity, which was consistent with the findings of ex vivo imaging. These results support the potential of KSNP117 as a promising lymphatic tracer for biomedical imaging applications.

Near-infrared laparoscopy with indocyanine green for axillary sentinel lymph node biopsy in early breast cancer: preliminary experience of a single unit

Background

A sentinel lymph node biopsy (SLNB) is a routine procedure for axillary staging in cN0 breast cancer (BC) patients. Indocyanine green (ICG) fluorescence can detect sentinel lymph nodes with higher sensitivity than carbon nanoparticle suspension (CNS). The present study investigated the availability and benefits of a near-infrared (NIR) laparoscopy-assisted SLNB using ICG and carbon nanoparticle suspension as tracers.

Methods

Forty patients with invasive BC, who had clinically negative axillary lymph nodes, participated in this observational study. ICG and CNS tracers were injected into the periareolar region simultaneously or sequentially. In the endoscopy-assisted group (n=20), the patients were given NIR laparoscopic SLNB based on ICG fluorescence and CNS staining. In the open-surgery group, the patients were given traditional SLNB using an open incision, and CNS tracers were injected into the same region as that in the endoscopy-assisted group.

Results

In the endoscopy-assisted group, lymphatic vessels and sentinel lymph nodes (SLNs) were successfully identified using ICG fluorescence imaging in most patients (19/20). The average number of SLNs removed was 2.85 (range, 1-4) in the endoscopy-assisted group, and 3.40 (range, 1-7) in the open-surgery group. There was no significant difference between the number of detected nodes (P=0.30). The patients who underwent endoscopy-assisted SLNBs had similar operating times, blood loss and hospital-stay lengths, but lower postoperative drainage volumes and higher satisfaction scores, as they did not have axillary incisions.

Conclusions

The NIR laparoscopy-assisted ICG-guided technique is a feasible and surgeon-friendly method for SLNB with good efficacy and acceptable safety. When combined with CNS, more SLNs can be detected and dissected.

Novel Experience in Hybrid Tracers: Clinical Evaluation of Feasibility and Efficacy in Using ICG-99mTc Nanotop for Sentinel Node Procedure in Breast Cancer Patients

PURPOSE

The clinical introduction of a radioactive and fluorescent hybrid tracer allowed for preoperative lymphatic mapping and intraoperative real-time fluorescence tracing of the sentinel lymph node (SLN) by a single injection. The aim of this feasibility study is to evaluate the first-in-human use of the hybrid tracer by combining indocyanine green (ICG) and radiocolloid based on Nanotop compound (99mTc Nanotop) for SLN biopsy (SLNB) in breast cancer patients.

METHODS

The day before surgery, ICG-99mTc Nanotop was injected periareolarly in breast cancer patients scheduled for SLNB. Planar lymphoscintigraphic (PL) and SPECT/CT images were then acquired. An intraoperative optonuclear probe was used to detect SLN gamma and fluorescent signals. The harvested SLNs were examined by hematoxylin-eosin staining, and patients were clinically evaluated 1 month after surgery.

RESULTS

Twenty-one consecutive patients were enrolled. The PL and SPECT/CT techniques identified at least 1 SLN in all patients for a preoperative sentinel detection rate of 100%. SPECT/CT revealed 3 additional lymph nodes in the same nodal basin, which had not been visualized on conventional PL (κ = 0.747; P < 0.005). All 30 preoperative SLNs were localized and excised up to 16 hours after injection. The counts measured via gamma tracing showed a very strong correlation with those measured via near-infrared fluorescent tracing (P < 0.005, r = 0.964). No adverse reactions were observed.

CONCLUSIONS

The SLNB technique used with the ICG-99mTc Nanotop tracer resulted to be feasible, reliable, and safe. This hybrid compound allowed us to obtain excellent performance in terms of both preoperative lymphatic mapping and intraoperative SLN detection in breast cancer patients.

Imaging technology of the lymphatic system

The lymphatic system plays critical roles in tissue fluid homeostasis and immunity and has been implicated in the development of many different pathologies, ranging from lymphedema, the spread of cancer to chronic inflammation. In this review, we first summarize the state-of-the-art of lymphatic imaging in the clinic and the advantages and disadvantages of these existing techniques. We then detail recent progress on imaging technology, including advancements in tracer design and injection methods, that have allowed visualization of lymphatic vessels with excellent spatial and temporal resolution in preclinical models. Finally, we describe the different approaches to quantifying lymphatic function that are being developed and discuss some emerging topics for lymphatic imaging in the clinic. Continued advancements in lymphatic imaging technology will be critical for the optimization of diagnostic methods for lymphatic disorders and the evaluation of novel therapies targeting the lymphatic system.

Tumor Accumulation and Off-Target Biodistribution of an Indocyanine-Green Fluorescent Nanotracer: An Ex Vivo Study on an Orthotopic Murine Model of Breast Cancer

Indocyanine green (ICG) is a near infrared fluorescent tracer used in image-guided surgery to assist surgeons during resection. Despite appearing as a very promising tool for surgical oncology, its employment in this area is limited to lymph node mapping or to laparoscopic surgery, as it lacks tumor targeting specificity. Recently, a nanoformulation of this dye has been proposed with the aim toward tumor targeting specificity in order to expand its employment in surgical oncology. This nanosystem is constituted by 24 monomers of H-Ferritin (HFn), which self-assemble into a spherical cage structure enclosing the indocyanine green fluorescent tracer. These HFn nanocages were demonstrated to display tumor homing due to the specific interaction between the HFn nanocage and transferrin receptor 1, which is overexpressed in most tumor tissues. Here, we provide an ex vivo detailed comparison between the biodistribution of this nanotracer and free ICG, combining the results obtained with the Karl Storz endoscope that is currently used in clinical practice and the quantification of the ICG signal derived from the fluorescence imaging system IVIS Lumina II. These insights demonstrate the suitability of this novel HFn-based nanosystem in fluorescence-guided oncological surgery.

Comparison of indocyanine green fluorescence and methylene blue dye in the detection of sentinel lymph nodes in breast cancer

Background

Previous studies have shown that sentinel lymph node biopsy (SLNB) can be successfully performed using methylene blue (MB); however, this method still has some drawbacks. Indocyanine green (ICG) fluorescence imaging, as a selective method, has the potential for guiding SLNB. This study aimed to compare the clinical sensitivity and efficacy between ICG and MB in SLNB in breast cancer.

Methods

A prospective study of 70 patients with biopsy-proven invasive breast cancer was conducted. Under the guidance of ICG and MB, administered by injection, SLNs were examined and removed. The detection rates, total number of SLNs detected, mean number of SLNs detected, and number of positive SLNs were compared between ICG and MB.

Results

The SLN detection rate was 100% and 93% (65/70) for ICG and MB, respectively. More SLNs were detected in the ICG group (243) than in the MB group (169). The mean number of SLNs detected with ICG and MB was 3.5±1.73 and 2.4±1.49, respectively. Moreover, there was a statistically significant difference between the number of SLNs detected using the two methods (t=6.648, P<0.05). Additionally, SLN metastasis was detected in 18 patients using ICG and 14 patients using MB; these patients immediately underwent axillary lymph node dissection (ALND). No postoperative complications were reported.

Conclusions

ICG demonstrated a higher detection rate and better accuracy, as well as a lower false negative rate, than MB in detecting SLNs in breast cancer. ICG has potential as an alternative tool that could be clinically applied to detect SLNs in breast cancer patients.

Systematic review and meta-analysis concerning near-infrared imaging with fluorescent agents to identify the sentinel lymph node in oncology patients

Sentinel node procedures (SNP) are performed with the use of tracer-agents, mainly radio-colloid and/or blue dye. Fluorescent agents have emerged as a new tracer-agent to identify the SLN intra-operatively with near-infrared imaging. Our aim is to compare the detection rate of fluorescent agents to current "golden standards" (blue dye and/or radio-colloid) for the SNP by means of a systematic review and meta-analysis without any restrictions based on tumor type. A systematic search in PubMed, Embase and The Cochrane Library was performed. Articles that compared the detection rates of fluorescent agents with radio-colloid and/or blue dye were included. Meta-analyses were performed for breast, gynecological and dermatological cancer using a random effects model. In total 6195 articles were screened which resulted in a final inclusion of 55 articles. All studies used indocyanine green (ICG) as fluorescent agent. Meta-analyses comparing ICG with blue dye showed a significant and clinically relevant difference in detection rate in favor of ICG, for both breast, dermatological and gynecological cancer. Meta-analyses comparing ICG with radio-colloid did not show any significant differences, with the exception of ICG versus radio-colloid + blue dye for the bilateral SLN detection in gynecological cancer. Near-infrared fluorescence imaging using ICG provides a higher detection rate compared to blue dye for the SNP in a range of different tumor types. SLN detection rates of ICG are comparable to radio-colloid. Due to their complementary characteristics in terms of spatial resolution and transdermal sensitivity, we suggest to use a combination of both ICG and a radio-colloid.

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

BACKGROUND

The objective of this study was to assess the detection and accuracy of sentinel lymph node (SLN) biopsy (SLNB) using the low-cost indocyanine green (ICG) fluorescence method and to compare this method with the gold standard dual-dye method (radio-colloid + methylene blue dye [MB]).

MATERIALS AND METHODS

One hundred patients with node-negative early breast cancer assessed clinically and by ultrasound axilla underwent an SLNB procedure using technetium-99m radio-colloid, MB, and ICG. The detection rate of SLNs and positive SLNs and the number of SLNs were compared. The injection safety of ICG and MB was evaluated.

RESULTS

One hundred female patients with a median age of 52.3 years participated in the study. Sixty-eight percent had a body mass index < 25, 85% presented with a palpable lump, of which 59% were in the outer quadrant. SLNs were identified in all 100 cases. A total of 290 SLNs were removed (mean, 2.9; range, 1-6). The identification rate with dual dye was 94%, whereas with ICG alone, it was 96%. The SLNB sensitivity rate and false negative rate were 97.6% versus 93.2% and 3.1% versus 6.2% in the ICG and dual-dye combination, respectively. None of the patients had any local or systemic reaction with ICG; 3 patients with blue dye had tattooing and staining of skin.

CONCLUSION

ICG fluorescence imaging permits real time visualization of lymphatics and provides an additional dimension to SLN biopsy that is safe and effective. These results confirm high sensitivity for fluorescence localization with comparable performance to the gold standard. ICG can reliably replace dual dye and be employed as a sole tracer for SLNB in early breast cancer.

Use of indocyanine green fluorescence compared to radioisotope for sentinel lymph node biopsy in early-stage breast cancer: systematic review and meta-analysis

BACKGROUND

In early-stage breast cancer, indocyanine green (ICG)-fluorescence based sentinel lymph node (SLN) detection is being considered. This is a meta-analysis of SLN detection rates and sensitivity of ICG-fluorescence compared to radioisotope (RI), to evaluate its clinical applicability.

DATA SOURCES

Systematic review of full-text articles from PubMed and Scopus, of women with early breast cancer who underwent SLN mapping using ICG and RI concurrently was performed. The meta-analysis was performed using the Mantel-Haenszel method.

RESULTS

2301 patients from 19 studies were included. No significant difference was observed between ICG and RI for SLN detection (OR0.90,95%CI0.66-1.24) or sensitivity (OR1.23,95%CI0.73-2.05) with heterogeneity between studies (I² = 58%,P = 0.003). Sensitivity of dual mapping (ICG + RI) was significantly better compared to single mapping with RI (OR3.69,95%CI1.79-7.62) or ICG (OR3.32,95%CI1.52-7.24) alone with no heterogeneity between studies (I² = 0%,P = 0.004).

CONCLUSION

ICG-fluorescence could complement RI method or provide alternative in centers with poor accessibility to RI lymphoscintigraphy.

New Technologies for Sentinel Lymph Node Detection

The 'standard of care' method for sentinel node mapping is the combination technique using radioisotope and blue dye although some centres use radioisotope or blue dye alone. Radioisotope usage requires licensing, has regulatory issues around handling and disposal of waste, and logistically may be unavailable or difficult to implement in some centres or less developed country. This has led to the development of alternative methods such as superparamagnetic iron oxide (SPIO), fluorescence techniques using indocyanine green (ICG) or fluorescein, computed tomography lymphography, and contrast-enhanced ultrasound scan (CEUS) using microbubbles. The newer techniques will potentially enable a more widespread adoption of this procedure; however, a common barrier for these techniques is the lack of standardisation and no randomised trials to evaluate their effectiveness against the current standard of care. Furthermore, many of these techniques are more costly and may become redundant in node-negative patients with small tumours if ongoing trials show that sentinel node biopsy offers no additional benefit to grey-scale axillary ultrasound. This review discusses the new techniques for sentinel node mapping that have emerged including their pros and cons.

Indocyanine-Green Fluorescence-GUIDED Liver Resection of Metastasis from Squamous Cell Carcinoma Invading the Biliary Tree

Background. The concept of fluorescence-guided navigation surgery based on indocyanine green (ICG) is a developing interest in many fields of surgical oncology. The technique seems to be promising also during hepatic resection. Case Presentation. We reported our experience of ICG-fluorescence-guided liver resection of metastasis located at VIII Couinaud's segment from colon squamous cell carcinoma of a 74-year-old male patient. Results. After laparotomy, the fluorescing tumour has been clearly identified on the liver surface. We have also identified that a large area of fluorescent parenchyma that gets from the peripheral of the lesion up to the portal pedicle such as the neoplasia would interest the right biliary tree in the form of neoplastic lymphangitis. This datum was not preoperatively known. Conclusion. Fluorescent imaging navigation liver resection could be a feasible and safe technique helpful in identifying additional characteristics of lesion. It could be a powerful tool but further studies are required.