Indocyanine green for sentinel lymph node detection in early breast cancer: Prospective evaluation of detection rate and toxicity-The FLUOBREAST trial

Utilization of indocyanine green for intraoperative sentinel lymph node mapping in canine mammary tumors

Accurate staging by sentinel lymph node (SLN) biopsy is essential for improving prognostic outcomes of canine mammary tumors (CMT). Indocyanine green near-infrared fluorescence (ICG-NIRF) imaging offers a novel real-time approach for SLN mapping, potentially enhancing the precision of surgical SLN biopsies. This study evaluated the effectiveness of transcutaneous ICG-NIRF imaging in identifying lymphatic drainage pathways and SLNs in CMT and determined the optimal ICG concentration for visualizing lymphatic channels and SLNs. We hypothesized that transcutaneous ICG-NIRF imaging effectively highlights both lymphatic channels and SLNs, facilitating accurate SLN biopsies. This study included 24 female dogs with cytologically diagnosed malignant CMT, from September 2023 to April 2024. ICG was injected peritumorally (concentrations: 0.5, 1.0, and 2.5 mg/mL). NIRF imaging was conducted intraoperatively to visualize lymphatic drainage and identify SLNs. Data on signal-to-background ratio of lymphatic drainage and SLN and operation time were collected and analyzed using ANOVA and post-hoc Tukey tests. The detection rate of SLNs using ICG-NIRF was 94.4% (34/36). Highest LN fluorescence (p = 0.030) and shortest operation time (p = 0.002) were yielded by 1.0 mg/mL ICG, with minimal false-negative rates (0%, 0/18). ICG-NIRF imaging enhances the accuracy of sentinel lymph node mapping in CMT by enabling real-time visualization of lymphatic drainage, optimizing lymph node biopsy selection, and improving surgical precision, thereby contributing to more accurate tumor staging and better prognostic assessment.

Indocyanine green for axillary sentinel lymph node biopsy in patients with breast cancer (INSEAN study)

INTRODUCTION

Sentinel lymph node (SLN) detection is the technique of choice for staging early-stage breast cancer (BC). The preferred technique for SLN detection is labelling with the radioisotope Technetium-99 (Tc-99). Other methods have been evaluated, including methylene blue, magnetic tracers, iodine seeds, or fluorescent substances. Various studies have shown the non-inferiority of indocyanine green (ICG) for SLN detection; however, inclusion criteria are selective and restrictive.

MAIN AND SECONDARY HYPOTHESES

Main hypotheses: SLN detection using ICG provides results that are not inferior to those obtained with Tc-99. Secondary hypotheses: METHODS AND DESIGN: This is a multicenter, prospective, observational study in BC patients undergoing primary or post-neoadjuvant surgery with SLN detection. INSEAN study (NCT: 06378944).

INCLUSION CRITERIA

Patients of both sexes with cN0 BC undergoing primary surgery or cN1 with good axillary response post-neoadjuvant. The detected nodes will be classified according to the detection method used as "Tc," "Tc + ICG," or "ICG." Final anatomopathological (AP) analysis will be conducted for comparison.

DISCUSSION

The SLN detection rates will be compared across techniques, along with potential adverse effects, definitive AP results, and costs between the two techniques.

The Medical Basis for the Photoluminescence of Indocyanine Green

Indocyanine green (ICG), a near-infrared (NIR) fluorescent dye with unique photoluminescent properties, is a helpful tool in many medical applications. ICG produces fluorescence when excited by NIR light, enabling accurate tissue visualization and real-time imaging. This study investigates the fundamental processes behind ICG's photoluminescence as well as its present and possible applications in treatments and medical diagnostics. Fluorescence-guided surgery (FGS) has been transformed by ICG's capacity to visualize tumors, highlight blood flow, and facilitate lymphatic mapping, all of which have improved surgical accuracy and patient outcomes. Furthermore, the fluorescence of the dye is being studied for new therapeutic approaches, like photothermal therapy, in which NIR light can activate ICG to target and destroy cancer cells. We go over the benefits and drawbacks of ICG's photoluminescent qualities in therapeutic contexts, as well as current studies that focus on improving its effectiveness, security, and adaptability. More precise disease detection, real-time monitoring, and tailored therapy options across a variety of medical specialties are made possible by the ongoing advancement of ICG-based imaging methods and therapies. In the main part of our work, we strive to take into account the latest reports; therefore, we used clinical articles going back to 2020. However, for the sake of the theoretical part, the oldest article used by us is from 1995.

Indocyanine Green Fluorescence Plus Blue Dye for Sentinel Lymph Node Biopsy in Patients Undergoing Neoadjuvant Chemotherapy for Breast Cancer: A Multicenter, Prospective Cohort Study

BACKGROUND

Sentinel lymph node biopsy (SLNB) using radioisotope tracer plus blue dye is the gold standard after neoadjuvant chemotherapy (NAC) in initially cN1 breast cancer patients, but clinical use still has limitations. This study aims to examine diagnostic performance of dual indocyanine green (ICG) and methylene blue tracing for SLNB in patients who have completed NAC for breast cancer with initially cN1 disease.

METHODS

Adult women (20-80 years of age) scheduled to undergo NAC for biopsy-proven cT0-3N1M0 primary invasive breast cancer were consecutively enrolled in this prospective, multicenter, cohort study. Upon the completion of NAC, SLNB was conducted using ICG and methylene blue, followed by axillary lymph node dissection. The primary outcome was the detection rate (DR); secondary outcomes included the false-negative rate (FNR) and adverse events associated with the use of tracers.

RESULTS

A total of 156 patients were enrolled; all underwent SLNB after NAC. The median number of lymph nodes retrieved during SLNB was 3 (range: 0-11). The DR was 97.4% (152/156; 95% CI, 93.6%-99.0%). The FNR was 6.7% (4/60; 95% CI, 2.6%-15.9%). Negative predictive value was 95.7% (88/92; 95% CI, 89.4%-98.3%). In the subgroup analysis stratified by ycN status, FNR was 4.0% (1/25; 95% CI, 0.7%-19.5%) and 8.6% (3/35; 95% CI, 3.0%-22.4%) in the ycN0 and ycN+ subgroups, respectively. No allergic reaction was reported.

CONCLUSIONS

SLNB with ICG plus methylene blue achieved a high DR and a very low FNR in breast cancer patients with initially cN1 disease.

TRIAL REGISTRATION

ClinicalTrials.gov (https://www.

CLINICALTRIALS

gov/), NCT02869815.

Indocyanine Green Marking of Axillary Sentinel Lymph Nodes in Early Breast Cancer

Axillary sentinel lymph node excision (SLNE) in breast cancer patients with clinically node-negative disease may be carried out using different tracers. The standard tracer is technetium colloid (99mTc). Indocyanine green (ICG) can be used as an alternative. This study aimed to evaluate the clinical usefulness of this fluorescent dye in a standardized setting.

A prospective, single-center cohort study carried out at the University Gynecological Hospital of Rostock from September 2023 to May 2024 carried out sentinel lymph node marking using only ICG in patients with breast malignancies. The ICG injection was administered immediately after the induction of anesthesia. Detection of the sentinel lymph node (SLN) was done using a laparoscopy system suitable for ICG. The aim was to determine the detection rate (DR) for SLNs marked exclusively using ICG and to record any complications. The costs of using ICG to mark SLNs were compared with those for 99mTc marking.

During the study period, contraindications against marking with ICG were ascertained for five (3.8%) of 132 patients with planned SLNE. A total of 100 SLNEs were carried out after ICG marking in patients who met the inclusion criteria in the context of the study. A median of two SLNs were resected. The detection rate (DR) for SLNs was 98.0%. SLNs were identified in all obese patients. No serious systemic side effects occurred following ICG injection. Transient skin discoloration in the area around the injection site were observed in eight patients. The direct cost of ICG marking was 62.73 Euros, which was 170.36 Euros lower than the cost of 99mTc marking.

The detection rate of axillary SLNs marked using ICG is high and the method is cost-effective, has few side effects and can also be used in obese patients. Contraindications against the administration of ICG are rare. Marking with ICG is a good alternative to the 99mTc method and offers advantages in terms of costs, logistics, no exposure to radiation, and patient comfort.

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.

Assessing the Sentimag system for guiding sentinel node biopsies in patients with breast cancer

INTRODUCTION

Sentinel lymph node biopsy for breast cancer is a method to localize and excise the first draining lymph node from an invasive cancer of the breast. The histopathologic evaluation of the sentinel lymph node is used for predicting recurrence and survival and thus, guiding oncologists for treatment-decision making to administer adjuvant therapies. The ability to identify the sentinel node depends on methods to map lymphatic drainage from the breast to the sentinel node and accurately discriminate that node from other non-sentinel lymph nodes of the axilla.

AREAS COVERED

This review covers the clinical demand for technologies to assist the surgeon in intraoperative lymphatic mapping to specifically identify the sentinel lymph node in patients with breast cancer. Performance characteristics are reviewed for superparamagnetic iron oxide tracers used in lymphatic mapping compared to other current available technologies for lymphatic mapping.

EXPERT OPINION

The Magtrace (superparamagnetic iron oxide tracer) Sentimag (handheld magnetic probe) system is an FDA-approved technology for intraoperative lymphatic mapping to facilitate sentinel lymph node biopsy in breast cancer with technologic performance characteristics that are equivalent to 99Technetium-sulfur colloid. Barriers to broader utilization primarily center around the need for nonmetallic devices to be used for the conduct of surgery, which would interfere with the paramagnetic method for tracer localization.

Nano-tracers for sentinel lymph node detection: current trends in technique and application

Sentinel lymph node (SLN) detection and biopsy is a critical staging component for several cancers. Apart from established methods using dyes or radiolabeled colloids, newer techniques are emerging, like near-infrared fluorescent compounds, targeted molecular radiopharmaceuticals and magnetic nano-tracers. In the overview section of this review, we categorize SLN detection tracers based on their principle of use. We discuss the merits of existing tracers and provide a glimpse of in-development formulations. A subsequent clinical section explores the expanded role of SLN detection in management of various cancers, citing current medical guidelines and the leading conclusions of long-term clinical trials. The concluding section tries to provide a perspective of promising developments and the work required to bring them to clinical fruition.

[Diagnostic value of fluorescence lymphography for sentinel lymph node biopsy in breast cancer. Summary experience of several specialized centers]

OBJECTIVE

To study the diagnostic value of fluorescent lymphography for sentinel lymph node biopsy in breast cancer.

MATERIAL AND METHODS

The cohort study, conducted at 4 specilized centers between June 2019 and March 2024, included 333 patients with cT1-4 N0-1M0 breast cancer. 50 patients received neoadjuvant systemic therapy, 14 of them had single metastases, confirmed by cytological or histological methods, which clinically completely regressed after systemic treatment. Immediately before the operation, 1 ml (5mg) of indocyanine green was injected subareolarly or subcutaneously into the tumor projection. Fluorescence imaging was performed using various devices for ICG navigation in the open surgical field - MARS, IC-Flow, Stryker SPY-PHI, IC-GOR. In 78 patients after sentinel lymph node biopsy standard axillary lymphadenectomy was performed.

RESULTS

Detection level was 99.1%. The average number of sentinel lymph nodes was 3.4. Metastatic lesions of sentinel lymph nodes were detected in 54 of 330 patients (16.4%). The average number of metastatic lymph nodes was 1.6; in 90.7% of cases metastases to 1-2 lymph nodes were registered. Intraoperative morphological examination revealed metastases only in 59% of cases. No systemic adverse events were recorded. The false-negative error rate in the group of patients who underwent axillary lymphadenectomy was 6.6%. The overall accuracy of fluorescent lymphography for sentinel lymph node biopsy in breast cancer was 94%.

CONCLUSION

The SLNB technique using fluorescence lymphography is safe and highly accurate as a stand-alone method.

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.

Novel Dual Tracer Indocyanine Green and Radioisotope Versus Gold Standard Sentinel Lymph Node Biopsy in Breast Cancer: The GREENORBLUE Trial

BACKGROUND

The methods for sentinel lymph node (SLN) biopsy in breast cancer have been variable in type and number of tracers. Some units have abandoned the use of blue dye (BD) due to adverse reactions. Fluorescence-guided biopsy with indocyanine green (ICG) is a relatively novel technique. This study compared the clinical efficacy and costs between novel dual tracer ICG and radioisotope (ICG-RI) with "gold standard" BD and radioisotope (BD-RI).

METHODS

Single-surgeon study of 150 prospective patients with early breast cancer undergoing SLN biopsy (2021-2022) using ICG-RI compared with a retrospective cohort of 150 consecutive previous patients using BD-RI. Number of SLNs identified, rate of failed mapping, identification of metastatic SLNs, and adverse reactions were compared between techniques. Cost-minimisation analysis performed by using Medicare item numbers and micro-costing analysis.

RESULTS

Total number of SLNs identified with ICG-RI and BD-RI was 351 and 315, respectively. Mean number of SLNs identified with ICG-RI and BD-RI was 2.3 (standard deviation [SD] 1.4) and 2.1 (SD 1.1), respectively (p = 0.156). There were no cases of failed mapping with either dual technique. Metastatic SLNs were identified in 38 (25.3%) ICG-RI patients compared with 30 (20%) BD-RI patients (p = 0.641). There were no adverse reactions to ICG, whereas four cases of skin tattooing and anaphylaxis were associated with BD (p = 0.131). ICG-RI cost an additional AU$197.38 per case in addition to the initial cost for the imaging system.

CLINICAL TRIAL REGISTRATION

 ACTRN12621001033831.

CONCLUSIONS

Novel tracer combination, ICG-RI, provided an effective and safe alternative to "gold standard" dual tracer. The caveat was the significantly greater costs associated with ICG.

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 in diagnostics and reconstructive surgery for breast cancer]

OBJECTIVE

To analyze the efficacy of sentinel lymph node detection using indocyanine green (ICG) in breast cancer.

MATERIAL AND METHODS

The study included 153 breast cancer patients (stage 0-I-II-III, cN0 or cN1-ycN0) between October 2022 and April 2023. All patients underwent sentinel lymph node biopsy using ICG.

RESULTS

Sentinel lymph node was successfully detected in 150 cases out of 153 ICG injections. Optimal period between ICG injection and its accumulation in regional lymph nodes was 10-12 min. Sensitivity of sentinel lymph node detection was 98.0% that exceeds the approximate value of radioisotope method adopted as a standard (96.9-97.2%), as well as sensitivity of proprietary blue dye (90.6-95.0%). Specificity of this method was 100%.

CONCLUSION

The authors' experience regarding application of indocyanine green is consistent with numerous world statistics and proves the possibility of its effective use for sentinel lymph node biopsy. It is necessary to introduce this diagnostic method as a leading or alternative method for analysis of sentinel lymph node in national clinical guidelines.

Clinical significance of discordances in sentinel lymph node reactivity between radioisotope and indocyanine green fluorescence in patients with cN0 breast cancer

BACKGROUND

/Objective: To evaluate the usefulness of combining radioisotopes (RI) and indocyanine green (ICG) and investigate discordances in sentinel lymph node (SN) reactivity using each tracer in cN0 breast cancer patients.

METHODS

In total, 338 cN0 primary breast cancer patients who underwent SN biopsy with RI and ICG and axillary lymph node (ALN) dissection were included. SN positivity with RI, ICG, and a combination of RI and ICG was denoted as SN(RI), SN(ICG), and SN(RI+ICG), respectively. We retrospectively estimated metastatic SN detection rates, each method's discordance rate, and the correlation of discordances in SN reactivity with postoperative N staging.

RESULTS

The combination of RI and ICG had higher metastatic SN detection rates (99.7%) than RI or ICG alone (91.7% and 96.4%, respectively; p < 0.01). The discordance rate between SN(RI) and SN(ICG) in detecting metastatic SNs was 11.3% (38/337 cases). The absence of SN(RI), cT stage (cT2-3), higher histological grade (G3), and histological type (special type) were identified as risk factors of pN2-3 disease (odds ratios: 8.64, 2.56, 1.92, and 3.28, respectively; p < 0.01).

CONCLUSION

Discordances in SN reactivity between RI and ICG helps in identifying SN metastasis. Although the absence of SN(RI) is rare, it is a significant sign of advanced ALN metastases. The findings of our study indicate that ALN dissection should be considered for accurate nodal staging in such cases.

Co-injection of Bile and Indocyanine Green for Detecting Pancreaticobiliary Maljunction of Choledochal Cyst

The usage of near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) has gained popularity in many procedures in pediatric surgery. ICG generates fluorescent light only when it combines with a protein. We herein report a novel technique for detecting pancreaticobiliary maljunction (PBMJ) with co-injection of bile and ICG in laparoscopic choledochal cyst resection and hepaticojejunostomy for a pediatric patient. A 4-year-old girl presented with abdominal pain and intermittent vomiting. Enhanced computed tomography and magnetic resonance cholangiopancreatography showed a 17-mm type Ia choledochal cyst. Definitive PBMJ was not detected preoperatively. Laparoscopic choledochal cyst resection and hepaticojejunostomy were performed using five ports. A percutaneous silicon catheter was inserted into the gallbladder, and bile juice was aspirated. The amylase level of the bile juice was over 3 × 105 IU/L. The aspirated bile juice and ICG were mixed and co-injected into the gallbladder through the catheter. ICG combined with protein in bile juice and generated fluorescent light. Dilated common bile duct and pancreas were detected by NIR fluorescence imaging. This imaging technique was helpful for detecting the dissection margin of the distal side of the choledochal cyst inside the pancreatic tissue and preventing injury of the pancreatic tissue. This is the first case of ICG application for laparoscopic choledochal cyst resection in a pediatric patient. After resection of the choledochal cyst, laparoscopic hepaticojejunostomy was completely performed. Our technique is a safe and low-invasive method of detecting and excising the distal side of the cyst without a risk of radiography and residual bile duct.

Intraoperative fluorescence with indocyanine green in congenital cardiac surgery: Potential applications of a novel technology

Background

Achieving successful repair of congenital heart defects requires attention to detail. Careful evaluation of anastomotic site patency, reimplanted coronary arteries, location of epicardial coronaries, and myocardial perfusion may be necessary to ensure safe conduct of the operation and achieve excellent outcomes.

Methods

Intraoperative fluorescence angiography (IOFA) was performed using indocyanine green in patients undergoing the following procedures: coronary artery reimplantation, coronary artery unroofing, evaluation of intraoperative coronary anatomy, reoperation requiring ventriculotomy, coarctation/interrupted aortic arch repair, systemic-to-pulmonary artery shunt, Norwood procedure, thoracic duct localization, and vascular rings.

Results

The technique was feasible in all patients. No mortality or adverse events related to the dye were encountered. Adequate intraoperative imaging was obtained in 15 patients (20 images), which correlated well with postoperative studies. The imaging quality was superior for assessing shunt patency, myocardial perfusion, and anastomotic patency and determining the location of epicardial coronary arteries but was less so for assessing branch pulmonary arteries.

Conclusions

IOFA is a useful and safe technique that can provide a quick on-table assessment of a variety of congenital surgical procedures. This may help answer questions that can minimize postoperative interventions and help ensure a smooth perioperative course and excellent outcomes.