Randomized comparison of near-infrared fluorescence lymphatic tracers for sentinel lymph node mapping of cervical cancer

Review of Clinically Assessed Molecular Fluorophores for Intraoperative Image Guided Surgery

The term "fluorescence" was first proposed nearly two centuries ago, yet its application in clinical medicine has a relatively brief history coming to the fore in the past decade. Nowadays, as fluorescence is gradually expanding into more medical applications, fluorescence image-guided surgery has become the new arena for this technology. It allows surgical teams to real-time visualize target tissues or anatomies intraoperatively to increase the precision of resection or preserve vital structures during open or laparoscopic surgeries. In this review, we introduce the concept of near-infrared fluorescence guided surgery, discuss the recent and ongoing clinical trials of molecular fluorophores (indocyanine green, 5-aminolevulinic acid, methylene blue, IR-dye 800CW, pafolacianine) and their surgical goals, highlight key chemical and medical factors for imaging agent optimization, deliberate challenges and potential advantages, and propose a framework for integrating this technology into routine surgical care in the near future. The notable clinical achievements of these fluorophores over the past decade strongly indicates that the future of fluorescence in surgery is bright with many more patient benefits to come.

Indocyanine green in gynecologic surgery: Where do we stand? A literature review and meta-analysis

The main objective of this study was to review and perform a meta-analysis of current literature on the use of indocyanine green for sentinel lymph node detection in pelvic gynecologic cancer. We included all studies focusing on indications and procedures associated with the use of ICG in gynecologic surgery and available on the Medline and Pubmed database. For the meta-analysis, random effect models were used for estimation of the 95 % detection rate and 95 % confidence interval, and stratified analyses by cancer type, concentration and localization of injection were performed. A total of 147 articles were included, of which 91 were studied in a meta-analysis. Results concerning detection rate by indocyanine green injection site were found to be 95.1 % and 97.3 % respectively for intracervical injection in 2 or 4 quadrants, and 77.0 % and 94.8 % for hysteroscopic and intradermal injection respectively. Results concerning detection rate by cancer type were 95.8 %, 95.2 %, 94.7 % and 95.7 % respectively for cervical, endometrial, vulvar and endometrial/cervical cancers. Finally, the results concerning detection rate by indocyanine green concentration were 91.2 %, 95.7 %, 96.7 % and 97.7 % for concentrations of <1.25 mg/ml, 1.25 mg/ml, 2.5 mg/ml and 5 mg/ml respectively. In conclusion, indocyanine green is shown to allow highlighting of sentinel lymph nodes with good reliability with an overall indocyanine green detection rate of 95.5 %. Our literature review revealed that indocyanine green feasibility has also been demonstrated in several surgical contexts, notably for reconstructive surgery and detection of endometriosis.

Monitoring Distribution of the Therapeutic Agent Dimethyl Sulfoxide via Solvatochromic Shift of Albumin-Bound Indocyanine Green

We recently developed a novel hyperspectral excitation-resolved near-infrared fluorescence imaging system (HER-NIRF) based on a continuous-wave wavelength-swept laser. In this study, this technique is applied to measure the distribution of the therapeutic agent dimethyl sulfoxide (DMSO) by utilizing solvatochromic shift in the spectral profile of albumin-bound Indocyanine green (ICG). Using wide-field imaging in turbid media, complex dynamics of albumin-bound ICG are measured in mixtures of dimethyl sulfoxide (DMSO) and water. Phantom experiments are conducted to evaluate the performance of the HER-NIRF system. The results show that the distribution of DMSO can be visualized in the wide-field reflection geometry. One of the main purposes of the DMSO is to act as a carrier for other drugs, enhancing their effects by facilitating skin penetration. Understanding the solubility and permeability of drugs in vivo is very important in drug discovery and development. Hence, this HER-NIRF technique has great potential to advance the utilization of the therapeutic agent DMSO by mapping its distribution via the solvatochromic shift of ICG. By customizing the operational wavelength range, this system can be applied to any other fluorophores in the near-infrared region and utilized for a wide variety of drug delivery studies.

Indocyanine Green-based Glow Nanoparticles Probe for Cancer Imaging

Indocyanine green (ICG) is one of the FDA-approved near infra-red fluorescent (NIRF) probes for cancer imaging and image-guided surgery in the clinical setting. However, the limitations of ICG include poor photostability, high concentration toxicity, short circulation time, and poor cancer cell specificity. To overcome these hurdles, we engineered a nanoconstruct composed of poly (vinyl pyrrolidone) (PVP)-indocyanine green that is cloaked self-assembled with tannic acid (termed as indocyanine green-based glow nanoparticles probe, ICG-Glow NPs) for the cancer cell/tissue-specific targeting. The self-assembled ICG-Glow NPs were confirmed by spherical nanoparticles formation (DLS and TEM) and spectral analyses. The NIRF imaging characteristic of ICG-Glow NPs was established by superior fluorescence counts on filter paper and chicken tissue. The ICG-Glow NPs exhibited excellent hemo and cellular compatibility with human red blood cells, kidney normal, pancreatic normal, and other cancer cell lines. An enhanced cancer-specific NIRF binding and imaging capability of ICG-Glow NPs was confirmed using different human cancer cell lines and human tumor tissues. Additionally, tumor-specific binding/accumulation of ICG-Glow NPs was confirmed in MDA-MB-231 xenograft mouse model. Collectively, these findings suggest that ICG-Glow NPs have great potential as a novel and safe NIRF imaging probe for cancer cell/tumor imaging. This can lead to a quicker cancer diagnosis facilitating precise disease detection and management.

Bowel perfusion demonstrated using indocyanine green fluorescence imaging in two cases of strangulated ileus

We report the use of indocyanine green (ICG) fluorescence for intraoperative diagnosis in two cases of strangulated ileus. We successfully preserved the bowel and avoided postoperative complications by detecting adequate perfusion and no necrosis in the intestine's strangulated regions. In the first case, enhanced computed tomography (CT) revealed a closed loop intestine, which showed poor contrast, and we performed laparotomy with ICG fluorescence. In the second case, the CT scan revealed bowel obstruction without ascites. We conservatively treated the patient with the insertion of a long tube. The patient's condition did not improve, and we performed laparotomy using ICG fluorescence. In both of these cases, the visual observation during laparotomy showed that the ileum had dark-red discoloration. We demonstrated perfusion and preserved the ileum by injecting 2.5 mg of ICG intravenously; fluorescence was observed in the dark-red ileum using the PINPOINT system (Novadaq, Kalamazoo, MI, US). Both patients recovered successfully after the surgery with no adverse events. Our data suggest that ICG fluorescence imaging can be one of the decision-making modalities in patients with strangulated ileus.

Fluorescent Indocyanine Green versus Technetium-99m and Blue Dye for Bilateral SENTinel Lymph Node Detection in Stage I-IIA Cervical Cancer (FluoreSENT): protocol for a non-inferiority study

INTRODUCTION

Nowadays, two predominant methods for detecting sentinel lymph nodes (SLNs) in cervical cancer are in use. The most conventional method is a combination of a radiotracer, technetium-99m (^99mTc) and blue dye. More recently, another method for SLN mapping using indocyanine green (ICG) is becoming widely accepted. ICG is a fluorescent dye, visualised intraoperatively with near-infrared (NIR) fluorescence imaging, providing real-time visual navigation. The presumed advantages of ICG over ^99mTc, that is, being cheaper, non-radioactive and logistically more attractive, are only valuable if its detection rate proves to be at least non-inferior. Before omitting the well-functioning and evidence-based combined approach of ^99mTc and blue dye, we aim to provide prospective evidence on the non-inferiority of ICG with NIR fluorescence imaging.

METHODS AND ANALYSIS

We initiated a prospective non-inferiority study with a paired comparison of both SLN methods in a single sample of 101 patients with International Federation of Gynecology and Obstetrics (FIGO) stage IA-IB2 or IIA1 cervical cancer receiving primary surgical treatment. All patients undergo SLN mapping with ICG and NIR fluorescence imaging in adjunct to mapping with ^99mTc (including single photon emission computed tomography with X-ray computed tomography (SPECT/CT)) and blue dye. Surgeons start SLN detection with ICG while being blinded for the preoperative outcome of SPECT/CT to avoid biased detection with ICG. Primary endpoint of this study is bilateral SLN detection rate of both methods (ie, detection of at least one SLN in each hemipelvis). Since we compare strategies for SLN mapping that are already applied in current daily practice for different types of cancer, no additional risks or burdens are expected from these study procedures.

ETHICS AND DISSEMINATION

The current study is approved by the Medical Ethics Research Committee Utrecht (reference number 21-014). Findings arising from this study will be disseminated in peer-reviewed journals, academic conferences and through patient organisations.

TRIAL REGISTRATION NUMBER

NL9011 and EudraCT 2020-005134-15.

Sentinel node navigation surgery in cervical cancer: a systematic review and metaanalysis

Sentinel node navigation surgery (SNNS) is used in clinical practice for the treatment of cervical cancer. This study aimed to elucidate the appropriate sentinel lymph node (SLN) mapping method and assess the safety and benefits of SNNS. We searched the PubMed, Ichushi, and Cochrane Library databases for randomized controlled trials (RCT) and studies on SLN in cervical cancer from January 2012 to December 2020. Two authors independently assessed study quality and extracted data. We quantitatively analyzed the detection rate, sensitivity/specificity, and complications and reviewed information, including the survival data of SLN biopsy (SLNB) without pelvic lymphadenectomy (PLND). The detection rate of SLN mapping in the unilateral pelvis was median 95.7% and 100% and in the bilateral pelvis was median 80.4% and 90% for technetium-99 m (Tc) with/without blue dye (Tc w/wo BD) and indocyanine green (ICG) alone, respectively. The sensitivity and specificity of each tracer were high; the area under the curve of each tracer was 0.988 (Tc w/wo BD), 0.931 (BD w/wo Tc), 0.966 (ICG), and 0.977 (carbon nanoparticle). Morbidities including lymphedema, neurological symptoms and blood loss were associated with PLND. One RCT and five studies all showed SNNS without systematic PLND does not impair recurrence or survival in early-stage cervical cancer with a tumor size ≤ 2-4 cm. Both Tc w/wo BD and ICG are appropriate SLN tracers. SNNS can reduce the morbidities associated with PLND without affecting disease progression in early-stage cervical cancer.

Detection of the sentinel lymph node with hybrid tracer (ICG-[99mTc]Tc-albumin nanocolloid) in intermediate- and high-risk endometrial cancer: a feasibility study

PURPOSE

Indocyanine green (ICG) is frequently used for the detection of the sentinel lymph node (SLN) in gynecology, but it carries the loss of the presurgical SLN mapping provided by [99mTc]-based colloids. Hybrid tracers such as ICG-[99mTc]Tc-albumin nanocolloid combine the benefits of both components. The aim of this study was to evaluate the feasibility and applicability of this hybrid tracer injected by transvaginal ultrasound-guided myometrial injection of radiotracer (TUMIR) approach in the detection of SLNs in patients with intermediate- and high-risk EC.

METHODS

Fifty-two patients with intermediate- and high-risk EC underwent SLN biopsy after injection of a hybrid tracer using the TUMIR approach, followed by pelvic and paraaortic lymphadenectomy. SLNs were detected preoperatively by lymphoscintigraphic study and intraoperatively by gamma probe and near-infrared (NIR) optical laparoscopic camera.

RESULTS

Preoperative lymphatic drainage was obtained in 69% and intraoperative detection in 71.4% of patients. A total of 146 SLNs (4.17 SLNs/patient) were biopsied. Pelvic bilateral detection was observed in 57% of the women and paraaortic drainage in 34% of the patients. The radioactive component allowed the detection of SLN in 97.1% of the patients, while the fluorescent component detected 80%. In more than 17% of the patients with intraoperative detection, SLNs were detected only by the radioactive signal. Lymph node metastasis was identified in 14.3% of patients submitted to SLNB. The sensitivity and negative predictive value for metastatic involvement were 100%.

CONCLUSION

TUMIR injection of a hybrid tracer in patients with intermediate- and high-risk EC combines the benefits of the radiotracer and the fluorescence methods with a single tracer. The method increases the paraaortic detection rate and allows a potential increase in SLN detection. Notwithstanding, based on our findings, the radioactive component of the hybrid tracer cannot be obviated.

Sentinel Lymph Node Staging with Indocyanine Green for Patients with Cervical Cancer: The Safety and Feasibility of Open Approach Using SPY-PHI Technique

Simple Summary

While several studies have been conducted on the safety and efficacy of sentinel lymph node technique during minimally invasive radical hysterectomy and indicated that using indocyanine green alone is a better tracer agent, there is now high unmet medical need and growing demand for more data about sentinel lymph node detection and the most suitable tracer in open surgery for cervical cancer, especially after the publishing of the of Laparoscopic Approach to Cervical Cancer (LACC) Trial data. The aim of this study is to assess the feasibility and safety of sentinel lymph nodes with indocyanine green in cervical cancer patients undergoing radical hysterectomy in open surgery and to compare the detection rates of this tracer in the open versus laparoscopic approaches.

Abstract

(1) Background: Sentinel lymph node staging (SLN) with indocyanine green (ICG) in cervical cancer is the standard of care in most national and international guidelines. However, the vast majority of relevant studies about the safety and feasibility of this method are conducted on minimally invasive surgery; (2) Methods: This study is a retrospective analysis of a retrospective collected database of 76 consecutive patients with cervical cancers, who were operated laparoscopically (50%), or laparotomy (50%). Sentinel nodes were defined as the ICG-positive pelvic nodes in the first and second echelons. False negative cases were defined as positive non-sentinel lymph nodes despite successful sentinel mapping or failed mapping bilaterally by per-patient assessment or unilaterally by pelvic sidewall assessment; (3) Results: Regardless of the approach (open or laparoscopic), the SLN technique achieved a total sensitivity, specificity, and negative predictive value (NPV) of 94.7%, 98.6%, and 94.7%, respectively in the entire sample. The bilateral detection rate was as high as 93.4% with identical results in both approaches. The sensitivity and NPV for SNL in open surgery was found to be similar to minimal access surgery; (4) Conclusions: ICG and SPY-PHI technique is a reliable tool to detect sentinel lymph nodes in cervical cancer during laparotomy.

Clinical implications of Indocyanine Green Fluorescence Imaging-Guided laparoscopic lymphadenectomy for patients with gastric cancer: A cohort study from two randomized, controlled trials using individual patient data

BACKGROUND

The value of indocyanine green (ICG) fluorescence imaging in tracing metastatic lymph nodes (LNs) has rarely been reported. We aimed to evaluate the clinical implications of fluorescence imaging-guided lymphadenectomy and the sensitivity of fluorescent lymphography to detect metastatic LN stations in gastric cancer (GC).

MATERIALS AND METHODS

This analysis pooled data from two randomized controlled trials (FUGES-012 and FUGES-019 studies) on laparoscopic ICG tracer-guided lymphadenectomy for GC between November 2018 and October 2020. Patients who received ICG injection using either the intraoperative subserosal or preoperative submucosal approaches 1 day before surgery and underwent fluorescence imaging-guided lymphadenectomy were defined as the ICG group. Patients who underwent conventional lymphadenectomy without ICG injection and intraoperative imaging were defined as the non-ICG group.

RESULTS

Among 514 enrolled patients, the ICG and non-ICG groups included 385 and 129, respectively. A significantly higher mean number of LNs was retrieved in the ICG group than in the non-ICG group (49.9 vs. 42.0, P < 0.001). The ICG group showed a lower LN noncompliance rate than that in the non-ICG group (31.9% vs. 57.4%, P < 0.001). The sensitivity of fluorescence imaging for detecting all metastatic LN stations was 86.8%. The negative predictive value was 92.2% for nonfluorescent stations. For detecting all metastatic stations, subgroup analysis revealed 97.7%, 91.7%, 86.2%, and 84.3% sensitivities for pT1, pT2, pT3, and pT4a tumors, respectively. Regardless of gastrectomy type, the diagnostic accuracy for detecting all metastatic stations in the D1+ and D2 stations for cT1-cT2 disease reached 100%.

CONCLUSION

ICG fluorescence imaging, using either the subserosal or submucosal approaches, assisted in the thorough dissection of potentially metastatic LNs, as recommended for individualized laparoscopic lymphadenectomy for GC.

Indocyanine green versus technetium-99m with blue dye for sentinel lymph node detection in early-stage cervical cancer: A systematic review and meta-analysis

Background

The fluorescent dye indocyanine green (ICG) has emerged as a promising tracer for intraoperative detection of sentinel lymph nodes (SLNs) in early‐stage cervical cancer. Although researchers suggest the SLN detection of ICG is equal to the more conventional combined approach of a radiotracer and blue dye, no consensus has been reached.

Aims

We aimed to assess the differences in overall and bilateral SLN detection rates with ICG versus the combined approach, the radiotracer technetium‐99m (^99mTc) with blue dye.

Methods and Results

We searched MEDLINE, Embase, and the Cochrane Library from inception to January 1, 2020 and included studies reporting on a comparison of SLN detection with ICG versus ^99mTc with blue dye in early‐stage cervical cancer. The overall and bilateral detection rates were pooled with random‐effects meta‐analyses.

From 118 studies retrieved seven studies (one cross‐sectional; six retrospective cohorts) were included, encompassing 589 patients. No significant differences were found in the pooled overall SLN detection rate of ICG versus ^99mTc with blue dye. Meta‐analyses of all studies showed ICG to result in a higher bilateral SLN detection rate than ^99mTc with blue dye; 90.3% (95%CI, 79.8‐100.0%) with ICG versus 73.5% (95%CI, 66.4‐80.6%) with 99mTc with blue dye. This resulted in a significant and clinically relevant risk difference of 16.6% (95%CI, 5.3‐28.0%). With sensitivity analysis, the risk difference of the bilateral detection rate maintained in favor of ICG but was no longer significant (13.2%, 95%CI −0.8‐27.3%).

Conclusion

ICG appears to provide higher bilateral SLN detection rates compared to ^99mTc with blue dye in patients with early‐stage cervical cancer. However, in adherence with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines, the quality of evidence is too low to provide strong recommendations and directly omit the combined approach of ^99mTc with blue dye.

Sentinel lymph node mapping with indocyanine green in cervical cancer patients undergoing open radical hysterectomy: a single-institution series

PURPOSE

To assess the rate of bilateral sentinel lymph node (SLN) detection with indocyanine green (ICG), to evaluate the sensitivity and the negative predictive value of cervical cancer patients undergoing open radical hysterectomy; to compare open versus minimally invasive SLN biopsy performance and to assess factors related to no/unilateral SLN mapping.

METHODS

We retrospectively reviewed consecutive patients with FIGO 2018 stage IA1 with lymph-vascular space involvement to IIB and IIIC1p cervical carcinoma who underwent SLN mapping with ICG followed by systematic pelvic lymphadenectomy between 05/2017 and 06/2020. Patients were divided according to surgical approach for statistical analysis.

RESULTS

Eighty-five patients met inclusion criteria. Twenty-seven (31.8%) underwent open and 58 (68.2%) underwent minimally invasive SLN mapping. No difference in any SLN mapping (laparotomy 92.6% and minimally invasive 91.4%) or in SLN bilateral detection (laparotomy 72.0% and minimally invasive 84.9%) (p = 0.850 and p = 0.222, respectively), in median number of SLNs mapped and retrieved (2 in both groups, p = 0.165) and in site of SLN mapping per hemi-pelvis (right side, p = 0273 and left side, p = 0.618) was evident between open and minimally invasive approach. Per-patient sensitivity of SLN biopsy in laparotomy was 83.3% (95% CI 35.9-99.6%) and the negative predictive value was 95.0% (95% CI 76.0-99.1%). No difference in per-patient sensitivity was noted between two approaches (p = 0.300). None of the analyzed variables was associated with no/unilateral SLN mapping.

CONCLUSION

The use of ICG to detect SLN in cervical cancer treated with open surgery allows a bilateral detection, sensitivity and negative predictive value comparable to minimally invasive surgery with potential advantages of ICG compared to other tracers.

Small Molecules for Multi-Wavelength Near-Infrared Fluorescent Mapping of Regional and Sentinel Lymph Nodes in Colorectal Cancer Staging

Assessing lymph node (LN) status during tumor resection is fundamental for the staging of colorectal cancer. Current guidelines require a minimum of 12 LNs to be harvested during resection and ultra-staging regional lymph nodes by sentinel lymph node (SLN) assessment is being extensively investigated. The current study presents novel near-infrared (NIR) fluorescent dyes for simultaneous pan lymph node (PanLN; regional) and SLN mapping. PanLN-Forte was intravenously injected in mice and assessed for accumulation in regional LNs. SLN800 was injected intradermally in mice, after which the collection and retention of fluorescence in SLNs were measured using indocyanine green (ICG) and its precursor, SLN700, as references. LNs in the cervical, inguinal, jejunal, iliac, and thoracic basins could clearly be distinguished after a low dose intravenous injection of PanLN-Forte. Background fluorescence was significantly lower compared to the parent compound ZW800-3A (p < 0.001). SLN700 and SLN800 specifically targeted SLNs with fluorescence being retained over 40-fold longer than the current clinically used agent ICG. Using SLN700 and SLN800, absolute fluorescence in SLN was at least 10 times higher than ICG in second-tier nodes, even at 1 hour post-injection. Histologically, the fluorescent signal localized in the LN medulla (PanLN-Forte) or sinus entry (SLN700/SLN800). PanLN-Forte and SLN800 appear to be optimal for real-time NIR fluorescence imaging of regional and SLNs, respectively.

Utility of Intraoperative Fluorescence Imaging in Gynecologic Surgery: Systematic Review and Consensus Statement

BACKGROUND

This study aimed to review the current knowledge on the utility of intraoperative fluorescence imaging in gynecologic surgery and to give evidence-based recommendations to improve the quality of care for women who undergo gynecologic surgery.

METHODS

A computer-based systematic review of the MEDLINE, CENTRAL, Pubmed, EMBASE, and SciSearch databases as well as institutional guidelines was performed. The time limit was set at 2000-2019. For the literature search, PRISMA guidelines were followed. A modified-Delphi method was performed in three rounds by a panel of experts to reach a consensus of conclusions and recommendations.

RESULTS

Indocyanine green (ICG) is used primarily in gynecology for sentinel node-mapping. In endometrial and cervical cancer, ICG is a feasible, safe, time-efficient, and reliable method for lymphatic mapping, with better bilateral detection rates. Experience in vulvar cancer is more limited, with ICG used together with Tc-99 m as a dual tracer and alone in video endoscopic inguinal lymphadenectomy. In early ovarian cancer, results are still preliminary but promising. Indocyanine green fluorescence imaging also is used for ureteral assessment, allowing intraoperative ureteral visualization, to reduce the risk of ureteral injury during gynecologic surgery.

CONCLUSIONS

For most gynecologic cancers, ICG fluorescence imaging is considered the tracer of choice for lymphatic mapping. The use of this new technology expands to a better ureteral assessment.

Sentinel lymph node in cervical cancer: a literature review on the use of conservative surgery techniques

INTRODUCTION

Sentinel lymph node detection is a surgical procedure that allow to avoid systematic lymphadenectomy in those tumors in early stage where lymph node spread is not sure. If the sentinel lymph node is not involved by tumor in 98-99% of case other lymph nodes are clean. The reason why less radical surgery is chosen is linked to the lower postoperative morbidity rate, the risk of lower limb lymphedema decreases. The aim of this review was to summarize what is the state of art of using the sentinel lymph node dissection (SLD) technique and what are the future goals to improve the safety and the reliability.

EVIDENCE ACQUISITION

We have conducted a review of the literature of the past 10 years to understand the attitudes of oncologist gynecologists in the world to the conservative treatment of cervical cancer. We only selected articles from 2010 onwards, which meet the inclusion criteria.

EVIDENCE SYNTHESIS

The detection rate varies from 83% to 100%. The bilateral detection rate, on the other hand, varies from 42% to 100%. The false negative rate ranges from 4% to 12%. Sensitivity varies from 20.7% (considering the frozen section) to 100%.

CONCLUSIONS

Indocyanine green is the most reliable and performing tracer for the search of the sentinel lymph node; that the false intraoperative negative rate is too high to be sure not to subject the patient to an incorrect therapeutic procedure; data concerning the safety and survival of conservative lymphadenectomy (SLND) compared to systematic lymphadenectomy are still lacking in the literature and therefore we are awaiting the results of the two ongoing randomized clinical trials that will allow us to have more significant scientific data.

Near-Infrared Fluorescent Image-Guided Lymphatic Mapping in Esophageal Squamous Cell Carcinoma

BACKGROUND

Recently, the feasibility of near-infrared (NIR) image-guided sentinel lymph node (SLN) mapping has been tested in patients with gastrointestinal cancer. The aim of this study is to investigate whether SLN mapping can be used to identify mediastinal lymph node metastases during minimally invasive esophagectomy and explore the lymphatic drainage pattern of esophageal squamous cell carcinoma (ESCC) using NIR fluorescent imaging.

PATIENTS AND METHODS

A total of 21 patients diagnosed with cT1-3 stage ESCC were enrolled. Patients received submucosal injection of indocyanine green diluted with sodium chloride (0.9%) at the start of the esophagectomy procedure followed by NIR mapping.

RESULTS

Thoracoscopic-assisted McKeown esophagectomy with NIR imaging was successfully performed in all patients. The detection rate and number of NIR+ lymph nodes were 95.2% (20/21) and 4.0 (2.0-6.5), respectively. The accuracy, false-negative rates, and negative predictive value were 100% (10 of 10 cases), 0% (0 of 4), and 100% (6 of 6), respectively, for pT1/T2 diseases; and 80.0% (8 of 10), 40% (2 of 5), and 71.4% (5 of 7), respectively, for pT3 diseases. The NIR+ region was the most commonly detected in the right recurrent laryngeal nerve (80%), and the NIR+ region was identified in the upper mediastinal zone in 20 patients.

CONCLUSIONS

Evaluation of the lymphatic drainage pattern and the application of sentinel lymph node in ESCC with real-time NIR imaging could be effective, especially in pT1/2 disease. NIR imaging-guided SLN navigation appears to be a clinically beneficial less-invasive method for treating ESCC.

Indocyanine Green Loaded Polymeric Nanoparticles: Physicochemical Characterization and Interaction Studies with Caco-2 Cell Line by Light and Transmission Electron Microscopy

Biomedical applications of nanoparticles (NPs) have reached an increasing development in recent years. Recently, we demonstrated that newly synthesized poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) are possible antitumor agents due to their cytotoxicity for cancer cells. Indocyanine green (ICG), an amphiphilic tricarbocyanine fluorescent dye, is widely used for the detection of tumoral extension in different organs during clinical surgery. Moreover, this fluorescent agent is unstable and it has a rapid clearance in physiological conditions in vivo. In this study, ICG was charged in PECA-NPs to improve its aqueous stability and make easier its use for the identification of tumor cells. Microscopic and ultrastructural aspects concerning the related in vitro interactions between ICG-loaded NPs and tumor cell culture were investigated. Obtained results showed an effective stabilization of ICG; furthermore, color inclusions inside the cells treated with ICG-loaded NPs demonstrated the internalization of NPs with associated ICG. Transmission electron microscopy (TEM) analysis demonstrated the cytoplasmic presence of coated vesicles (Ø ≤ 100 nm), hypothesizing their involvement in the mechanism of endocytosis. Therefore, ICG-loaded NPs could be proposed as agents for tumor diagnosis, hypothesizing also in the future a specific therapeutic treatment.

Pathologic Protocols for Sentinel Lymph Nodes Ultrastaging in Cervical Cancer

CONTEXT.—

Ultrastaging of sentinel lymph nodes (SLNs) is a crucial aspect in the approach to SLN processing. No consensual protocol for pathologic ultrastaging has been approved by international societies to date.

OBJECTIVE.—

To provide a review of the ultrastaging protocol and all its aspects related to the processing of SLNs in patients with cervical cancer.

DATA SOURCES.—

In total, 127 publications reporting data from 9085 cases were identified in the literature. In 24% of studies, the information about SLN processing is entirely missing. No ultrastaging protocol was used in 7% of publications. When described, the differences in all aspects of SLN processing among the studies and institutions are substantial. This includes grossing of the SLN, which is not completely sliced and processed in almost 20% of studies. The reported protocols varied in all aspects of SLN processing, including the thickness of slices (range, 1-5 mm), the number of levels (range, 0-cut out until no tissue left), distance between the levels (range, 40-1000 μm), and number of sections per level (range, 1-5).

CONCLUSIONS.—

We found substantial differences in protocols used for SLN pathologic ultrastaging, which can impact sensitivity for detection of micrometastases and even small macrometastases. Since the involvement of pelvic lymph nodes is the most important negative prognostic factor, such profound discrepancies influence the referral of patients to adjuvant radiotherapy and could potentially cause treatment failure. It is urgent that international societies agree on a consensual protocol before SLN biopsy without pelvic lymphadenectomy is introduced into routine clinical practice.

S122: impact of fluorescence and 3D images to completeness of lateral pelvic node dissection

BACKGROUND

Lateral pelvic lymph node dissection (LPND) is a technically demanding procedure. Consequently, there is a possibility of incomplete dissection of lateral pelvic lymph nodes (LPNs). We aimed to identify metastatic LPNs intraoperatively in real-time under dual guidance of fluorescence imaging and 3D lymphovascular reconstruction, and then to remove them completely.

METHODS

Rectal cancer patients who were scheduled to undergo LPND after preoperative chemoradiotherapy (CRT) were prospectively enrolled. We traced changes in suspected metastatic LPNs during preoperative CRT and defined them as index LPNs on post-CRT imaging studies. For fluorescence imaging, indocyanine green (ICG) at a dose of 2.5 mg was injected transanally around the tumor before the operation. For 3D reconstruction images, each patient underwent preoperative axial CT scan with contrast (0.6 mm slice thickness). These images were then manipulated with OsiriX. Index LPNs and essential structures in the pelvic sidewall, such as the obturator nerve, were reconstructed with abdominal arteries from 3D volume rendering. All surgical procedures were performed via laparoscopic or robotic approach.

RESULTS

From March to July 2017, ten rectal cancer patients underwent total mesorectal excision with LPND after preoperative CRT under dual image guidance. Bilateral LPND was performed in five patients. All index LPNs among ICG-bearing lymph nodes were clearly identified intraoperatively by matching with their corresponding 3D images. Pathologic LPN metastasis was confirmed in four patients (40.0%) and in five of the 15 dissected pelvic sidewalls (33.0%). All metastatic LPNs were identified among index LPNs. Four (80.0%) of the five metastatic LPNs were located in the internal iliac area.

CONCLUSION

Index LPNs among ICG-bearing lymph nodes in pelvic sidewall were clearly identified and completely removed by matching with their corresponding 3D reconstruction images. Further studies and long-term oncologic outcomes are required to determine the real impact of dual image guidance in LPND.

Cell membrane capsule: a novel natural tool for antitumour drug delivery

INTRODUCTION

Chemotherapy plays an important role in antitumour therapy, but causes serious adverse reactions. So, drug delivery system (DDS) with cell-targeting ability is an important method to reduce adverse reactions while ensuring the effectiveness of chemotherapy. Synthetic drug carriers and DDSs based on cells have proven safety and efficacy, but they also have many deficiencies or limitations. Cell membrane capsules (CMCs), which are based on extracellular vesicles (EVs), are a promising biomimetic DDS that retains some cell membrane channels and cytoplasmic functions, with escape macrophage phagocytosis.

AREAS COVERED

The EVs for constructing CMCs can be prepared by natural secretion, chemical-induced budding, nanofilter membrane extrusion and similar methods and are isolated and purified by a variety of methods such as centrifugation and liquid chromatography. CMCs can target the tumour cells either spontaneously or through targeting modifications using proteins or aptamers to actively target the tumour cells. CMCs can be directly wrapped with chemicals, photosensitizers, RNA, proteins and other ingredients, or they can be loaded with antitumour agent-loaded synthetic nanoparticles, which are delivered to the target cells to play a specific role.

EXPERT OPINION

This review describes the concept, function, characteristics, origins, and manufacturing methods of CMCs and their application in antitumour therapy.

Indocyanine green can stand alone in detecting sentinel lymph nodes in cervical cancer

OBJECTIVES

The effectiveness of indocyanine green (ICG) dye for detecting sentinel lymph nodes (SLNs) in cervical cancer compared with other tracers is unknown. This study aimed to assess the validity of ICG dye in detecting SLNs in cervical cancer preoperatively.

METHODS

We performed a literature search for identifying eligible articles from PubMed database using the search terms "cervical cancer", "sentinel lymph node", "indocyanine green", "blue dyes", "human serum albumin", and "technetium-99 radiocolloid". We performed a meta-analysis. Comparison of the overall, bilateral, and unilateral detection rates of the different tracers was the primary goal. Comparison of the false-negative rate among the tracers was the secondary goal.

RESULTS

Only eight retrospective studies including 661 patients were included. ICG versus combinations of three other tracers showed significantly higher bilateral and unilateral detection rates, but no difference in the overall rate of detecting SLNs. ICG had a higher bilateral detection rate than blue dye and technetium-99. Absorbing human serum albumin into ICG as a lymphatic tracer did not show a difference in detection rate compared with ICG alone.

CONCLUSIONS

ICG is superior and better than other tracers, and absorbing human serum albumin as a lymphatic tracer is not required in patients with cervical cancer.

Near infrared fluorescence light imaging for lymphatic flow toward para-aortic lymph node from the Calot's triangle: A prospective exploratory study

BACKGROUND

Metastasis to para-aortic lymph nodes (PAN) in hilar malignancies is considered distant metastasis. Fluorescence imaging using near infrared fluorescence light and indocyanine green (ICG-NIR imaging) are widely employed for identifying the sentinel lymph node, which might be an ideal alternative procedure for whole excisional biopsy of PAN. However, there has been no report about ICG-NIR imaging in hilar malignancies. The purpose of this study was to determine the optimal dose for indocyanine green to detect PAN and to reveal the detection rate of ICG-NIR imaging for lymphatic flow toward regional lymph nodes (RLN) or PAN from the Calot's triangle.

PATIENTS AND METHODS

We enrolled 62 patients with hepato-pancreatic-biliary malignancies in this study. The dose of ICG was optimized in the first 15 patients and the detection rate for RLN and PAN was evaluated in the remaining 47. We observed that the optimal administered dose of ICG for detecting fluorescent signals in PAN was 5 mg/mL.

RESULTS

Using this dose, RLN and PAN fluorescence were detected in 29 of 42 patients. Fluorescent signals were recorded in the lymph nodes (LN) along the bile duct and the posterior surface of the head of the pancreas. We also detected PAN fluorescent signals on the right side of the aorta around the left renal vein. We recommend 5 mg/ml of ICG to visualize lymphatic flow from the hepatoduodenal ligament to PAN using ICG-NIR imaging. However, because detection rate of RLN and PAN were 69%, respectively, further improvement for this procedure will be necessary for clinical application.

A practical guide for the use of indocyanine green and methylene blue in fluorescence-guided abdominal surgery

Near-infrared (NIR) fluorescence imaging is gaining clinical acceptance over the last years and has been used for detection of lymph nodes, several tumor types, vital structures and tissue perfusion. This review focuses on NIR fluorescence imaging with indocyanine green and methylene blue for different clinical applications in abdominal surgery with an emphasis on oncology, based on a systematic literature search. Furthermore, practical information on doses, injection times, and intraoperative use are provided.

NIR-I-to-NIR-II fluorescent nanomaterials for biomedical imaging and cancer therapy

This review discusses the recent development of nanomaterials with NIR-I-to-NIR-II fluorescence and their applications in biomedical imaging and cancer therapy.

Study on enhanced lymphatic tracing of isosulfan blue injection by influence of osmotic pressure on lymphatic exposure

Isosulfan blue (IB) is being used as a lymphatic tracer has been approved by the FDA in 1981. This study aimed at improving lymphatic exposure of IB injection by osmotic pressure regulation to achieve step-by step lymphatic tracing. First, IB injection with appropriate osmotic pressure, stability, and suitable pH was prepared. Next, the lymphatic tracing ability of different osmotic pressure was studied to determine the blue-stained state of IB in three-level lymph nodes after subcutaneous administration. Furthermore, pharmacokinetics of lymphatic drainage, lymph node uptake, and plasma concentration was investigate to explore the improving law of the lymphatic tracing by osmotic pressure, and combined with tissue irritation to determine the optimal osmotic pressure. At last, the tissue distribution in mice of IB injection which had the property of optimal osmotic pressure was investigated. The results showed that increasing osmotic pressure could significantly reduce injection site retention and increase IB concentration of lymph node. The lymph nodes could be obviously blue-stained by IB injection which had 938 mmol/kg osmotic pressure and would not cause inflammatory reaction and blood exposure. The tissue distribution study suggested that IB injection which had 938 mmol/kg osmotic pressure was mainly distributed into gallbladder and duodenum that verified the reports that 90% IB was excreted through the feces through biliary excretion. In conclusion, this study provides the basic study to improve lymphatic exposure of IB injection by regulate the osmotic pressure and have the potential to be the helpful guidance for the elective lymph node dissection.

Sentinel lymph node mapping in gynecological oncology

The intraoperative mapping of sentinel lymph nodes (SLNs) is part of the treatment strategy for a number of types of tumor. To retrospectively compare results from the mapping of pelvic SLNs for gynecological oncology, using distinct dyes, the present review was conducted to determine the clinical significance of SLN mapping for gynecological oncology. In addition, the present study aimed at identifying an improved choice for SLN mapping tracers in clinical application. Each dye exhibits demerits when applied in the clinical environment. The combination of radioisotopes and blue dyes was identified to exhibit the most accurate detection rate of SLN drainage of gynecological oncology. However, contrast agents were unable to identify whether a SLN is positive or negative for metastasis prior to pathologic examination; additional studies are required.

Intraoperative Real-Time Assessment of Liver Function with Near-Infrared Fluorescence Imaging

BACKGROUND

Postoperative liver failure is a serious complication after major hepatectomy, and perioperative prediction of its incidence using current technology is still very difficult. Near-infrared (NIR) fluorescence imaging allows quantitative assessment of the fluorescent signal from indocyanine green (ICG) in regions of interest on the liver surface. This method might offer a new promising modality for evaluating regional liver reserve. However, data are lacking regarding the relationship between liver function and fluorescent signals on the liver surface after intravenous ICG injection. This study was conducted to obtain the data necessary to apply NIR fluorescence imaging as a modality for measuring liver function.

MATERIALS AND METHODS

This study included 16 patients who underwent open hepatopancreatobiliary surgery between March 2011 and March 2012. After laparotomy, ICG was injected intravenously at 2.5 mg/L of liver volume, then the fluorescence intensity (FI) and signal-to-background ratio (SBR) in the lateral segment of the liver were assessed for 15 min. Intraoperative blood samples were also obtained to measure the plasma clearance rate of ICG (ICGK). Correlations between ICGK, liver volume, and SBR, as well as between ICGK, liver volume, and rate of change of FI were analyzed.

RESULTS

The experimental procedure was performed in all 16 patients. The FI of the liver increased rapidly after ICG injection, then became more gradual, reaching a near-plateau after 15 min. A significant correlation was seen between ICGK and the rate of change of FI up to 15 min (|rS| = 0.5725, p < 0.05).

CONCLUSION

This is the first report to show a relationship between liver function and fluorescent signals on the liver surface after intravenous ICG injection. Intraoperative NIR fluorescence imaging with ICG may be useful as a new method for assessing liver function.

Beyond the margins: real-time detection of cancer using targeted fluorophores

Over the past two decades, synergistic innovations in imaging technology have resulted in a revolution in which a range of biomedical applications are now benefiting from fluorescence imaging. Specifically, advances in fluorophore chemistry and imaging hardware, and the identification of targetable biomarkers have now positioned intraoperative fluorescence as a highly specific real-time detection modality for surgeons in oncology. In particular, the deeper tissue penetration and limited autofluorescence of near-infrared (NIR) fluorescence imaging improves the translational potential of this modality over visible-light fluorescence imaging. Rapid developments in fluorophores with improved characteristics, detection instrumentation, and targeting strategies led to the clinical testing in the early 2010s of the first targeted NIR fluorophores for intraoperative cancer detection. The foundations for the advances that underline this technology continue to be nurtured by the multidisciplinary collaboration of chemists, biologists, engineers, and clinicians. In this Review, we highlight the latest developments in NIR fluorophores, cancer-targeting strategies, and detection instrumentation for intraoperative cancer detection, and consider the unique challenges associated with their effective application in clinical settings.

Role of ICG-99mTc-nanocolloid for sentinel lymph node detection in cervical cancer: a pilot study

PURPOSE

Sentinel lymph node biopsy (SLNB) can be used for nodal staging in early cervical cancer. For this purpose, the tracers most commonly used are radiotracers based on technetium. For the last decade, indocyanine green (ICG) has been used as a tracer for SLNB in other malignancies with excellent results and, more recently, a combination of ICG and a radiotracer has been shown to have the advantages of both tracers. The aim of this study was to evaluate the role of ICG-^99mTc-nanocolloid in SLN detection in patients with cervical cancer.

METHODS

This prospective study included 16 patients with cervical cancer. The hybrid tracer was injected the day (19-21 h) before surgery for planar and SPECT/CT lymphoscintigraphy. Blue dye was administered periorificially in 14 patients. SLNs were removed according to their distribution on lymphoscintigraphy and when radioactive, fluorescent and/or stained with blue dye. Nodal specimens were pathologically analysed for metastases including by immunochemistry.

RESULTS

Lymphoscintigraphy and SPECT/CT showed drainage in all patients. A total of 69 SLNs were removed, of which 66 were detected by their radioactivity signal and 67 by their fluorescence signal. Blue dye identified only 35 SLNs in 12 of the 14 patients (85.7%). All patients showed bilateral pelvic drainage. Micrometastases were diagnosed in two patients, and were the only lymphatic nodes involved.

CONCLUSIONS

SLNB with ICG-^99mTc-nanocolloid is feasible and safe in patients with early cervical cancer. This hybrid tracer provided bilateral SLN detection in all patients and a higher detection rate than blue dye, so it could become an alternative to the combined technique.

Sentinel Lymphadenectomy in Vulvar Cancer Using Near-Infrared Fluorescence From Indocyanine Green Compared With Technetium 99m Nanocolloid

OBJECTIVE

Nowadays, sentinel diagnostic is performed using technetium 99m (Tc) nanocolloid as a radioactive marker and sometimes patent blue. In the last years, indocyanine green has been evaluated for sentinel diagnostic in different tumor entities. Indocyanine green is a fluorescent molecule that emits a light signal in the near-infrared band after excitation. Our study aimed to evaluate indocyanine green compared with the criterion-standard Tc-nanocolloid.

METHODS

We included patients with primary, unifocal vulvar cancer of less than 4 cm with clinically node-negative groins in this prospective trial. Sentinel diagnostic was carried out using Tc-nanocolloid, indocyanine green, and patent blue. We examined each groin for light signals from the near-infrared band, for radioactivity, and for blue staining. A sentinel lymph node was defined as a Tc-nanocolloid-positive lymph node. All sentinel lymph nodes and all additional blue or fluorescent lymph nodes were excised and tested and then sent for histologic examination.

RESULTS

In all, 27 patients were included in whom we found 91 sentinel lymph nodes in 52 groins. All these lymph nodes were positive for indocyanine green, also giving a sensitivity of 100% (95% confidence interval [CI], 96.0%-100%) compared with Tc-nanocolloid. Eight additional lymph nodes showed indocyanine green fluorescence but no Tc positivity, so that the positive predictive value was 91.9% (95% confidence interval, 84.6%-96.5%). In 1 patient, a false-negative sentinel missed by all 3 modalities was found.

CONCLUSIONS

Our results show that indocyanine green is a promising approach for inguinal sentinel identification in vulvar cancer with a similar sensitivity as radioactive Tc-nanocolloid and worth to be evaluated in further studies.

Sentinel Lymph Nodes Mapping in Cervical Cancer a Comprehensive Review

OBJECTIVE

A comprehensive literature search for more recent studies pertaining to sentinel lymph node mapping in the surveillance of cervical cancer to assess if sentinel lymph node mapping has sensitivity and specificity for evaluation of the disease; assessment of posttreatment response and disease recurrence in cervical cancer.

MATERIALS AND METHODS

The literature review has been constructed on a step wise study design that includes 5 major steps. This includes search for relevant publications in various available databases, application of inclusion and exclusion criteria for the selection of relevant publications, assessment of quality of the studies included, extraction of the relevant data and coherent synthesis of the data.

RESULTS

The search yielded numerous studies pertaining to sentinel lymph node mapping, especially on the recent trends, comparison between various modalities and evaluation of the technique. Evaluation studies have appraised high sensitivity, high negative predictive values and low false-negative rate for metastasis detection using sentinel lymph node mapping. Comparative studies have established that of all the modalities for sentinel lymph node mapping, indocyanine green sentinel lymph node mapping has higher overall and bilateral detection rates. Corroboration of the deductions of these studies further establishes that the sentinel node detection rate and sensitivity are strongly correlated to the method or technique of mapping and the history of preoperative neoadjuvant chemotherapy.

CONCLUSIONS

The review takes us to the strong conclusion that sentinel lymph node mapping is an ideal technique for detection of sentinel lymph nodes in cervical cancer patients with excellent detection rates and high sensitivity. The review also takes us to the supposition that a routine clinical evaluation of sentinel lymph nodes is feasible and a real-time florescence mapping with indocyanine green dye gives better statistically significant overall and bilateral detection than methylene blue.

Intraoperative Near-Infrared Fluorescence Imaging using indocyanine green in colorectal carcinomatosis surgery: Proof of concept

PURPOSES

This study assesses the value of using Intraoperative Near Infrared Fluorescence Imaging and Indocyanine green to detect colorectal carcinomatosis during oncological surgery. In colorectal carcinomatosis cancer, two of the most important prognostic factors are completeness of staging and completeness of cytoreductive surgery. Presently, intraoperative assessment of tumoral margins relies on palpation and visual inspection. The recent introduction of Near Infrared fluorescence image guidance provides new opportunities for surgical roles, particularly in cancer surgery.

METHODS

The study was a non-randomized, monocentric, pilot "ex vivo" blinded clinical trial validated by the ethical committee of University Hospital of Saint Etienne. Ten patients with colorectal carcinomatosis cancer scheduled for cytoreductive surgery were included. Patients received 0.25 mg/kg of Indocyanine green intravenously 24 h before surgery. A Near Infrared camera was used to detect "ex-vivo" fluorescent lesions.

RESULTS

There was no surgical mortality. Each analysis was done blindly. In a total of 88 lesions analyzed, 58 were classified by a pathologist as cancerous and 30 as non-cancerous. Among the 58 cancerous lesions, 42 were correctly classified by the Intraoperative Near-Infrared camera (sensitivity of 72.4%). Among the 30 non-cancerous lesions, 18 were correctly classified by the Intraoperative Near-Infrared camera (specificity of 60.0%).

CONCLUSIONS

Near Infrared fluorescence imaging is a promising technique for intraoperative tumor identification. It could help the surgeon to determine resection margins and reduce the risk of locoregional recurrence.

Optimal settings and accuracy of indocyanine green fluorescence imaging for sentinel node biopsy in early gastric cancer

Indocyanine green (ICG) fluorescence imaging represents a promising method for sentinel node (SN) biopsy in laparoscopic gastric surgery due to its signal stability. In the present study, the suitability and optimal settings of ICG fluorescence imaging for SN biopsy in early gastric cancer were determined. Patients with single primary superficial-type adenocarcinoma of the stomach, lesions <5 cm in diameter, and no evident nodal metastasis and out of indication for endoscopic submucosal dissection were enrolled. The day prior to surgery, ICG solution was endoscopically injected into four quadrants of the submucosal layer of the tumor. The Photodynamic Eye was used to detect ICG fluorescence. Bright nodes were defined as clearly fluorescent nodes. A total of 72 patients were enrolled; 11 cases presented with metastasis, and of these, 10 could be diagnosed by bright node biopsy. The adequate concentration and injection volume of ICG was determined to be 50 µg/ml (×100) and 0.5 mlx4 points, respectively. There was 1 false-negative case, and this was attributed to the failure of the frozen section diagnosis. These results suggested that ICG fluorescence imaging for SN biopsy in laparoscopic surgery for early gastric cancer is feasible. However, a weakness of ICG fluorescence imaging is the subjectivity of bright node evaluation.

Indocyanine green delivery systems for tumour detection and treatments

Indocyanine green (ICG) is a cyanine compound that displays fluorescent properties in the near infrared region. This dye is employed for numerous indications but nowadays its major application field regards tumour diagnosis and treatments. Optical imaging by near infrared fluorescence provides news opportunities for oncologic surgery. The imaging of ICG can be useful for intraoperative identification of several solid tumours and metastases, and sentinel lymph node detection. In addition, ICG can be used as an agent for the destruction of malignant tissue, by virtue of the production of reactive oxygen species and/or induction of a hyperthermia effect under irradiation. Nevertheless, ICG shows several drawbacks, which limit its clinical application. Several formulative strategies have been studied to overcome these problems. The rationale of the development of ICG containing drug delivery systems is to enhance the in vivo stability and biodistribution profile of this dye, allowing tumour accumulation and resulting in better efficacy. In this review, ICG containing nano-sized carriers are classified based on their chemical composition and structure. In addition to nanosystems, different formulations including hydrogel, microsystems and others loaded with ICG will be illustrated. In particular, this report describes the preparation, in vitro characterization and in vivo application of ICG platforms for cancer imaging and treatment. The promising results of all systems confirm their clinical utility but further studies are required prior to evaluating the formulations in human trials.

Safety and feasibility of near-infrared image-guided lymphatic mapping of regional lymph nodes in esophageal cancer

OBJECTIVE

To assess safety and feasibility of an intraoperative, minimally invasive near-infrared (NIR) image-guided approach to lymphatic mapping in patients with esophageal cancer.

METHODS

Although local lymph nodes (LNs) are removed with the esophageal specimen, no techniques are available to identify the regional LNs (separate from the esophagus) during esophagectomy. We hypothesize that NIR imaging can identify regional LNs with the potential to improve staging and guide the extent of lymphadenectomy. Nine of the 10 patients enrolled had resectable esophageal adenocarcinoma and underwent NIR mapping following peritumoral submucosal injection of indocyanine green (ICG) alone or premixed in human serum albumin (ICG:HSA) before resection. NIR imaging was performed in situ and ex vivo.

RESULTS

In 6 of the 10 patients, intraoperative NIR imaging demonstrated an NIR signal at all tumors and in 2 to 6 NIR(+) regional LNs. NIR(+) LNs were not identified in 4 patients: 1 patient with occult stage IV disease, for whom further imaging was not performed and thus was excluded from analysis, and 3 patients in whom ICG was used without HSA. Identification of local LNs on the esophagus was obscured by a peritumoral background. Importantly, the pathological status of NIR(+) regional LNs reflected overall regional nodal status.

CONCLUSIONS

NIR lymphatic mapping is safe and feasible in patients with esophageal cancer and can identify regional LNs when ICG:HSA is used. Although more work is needed to improve background signals and local LN identification, intraoperative detection of regional NIR(+) LNs allows an in-depth histological analysis of LN basins not commonly scrutinized as part of the specimen and may improve the detection of occult nodal disease.

Application of Deuteporfin in the Metastatic Lymph Node Mapping of Pancreatic Cancer: An in vivo Study

For most cancer patients, the presence of metastatic lymph nodes usually indicates regional recurrence and poor prognosis. Therefore, lymph node mapping is a requisite for disease staging, prognosis prediction and decision making in the treatment of cancer. Deuteporfin, a second-generation photosensitizer, has a maximum excitation wavelength that can reach the near infrared (NIR) region (650-700 nm). We aimed to take advantage of these aspects of deuteporfin and use it as a fluorescent probe for metastatic lymph node mapping in vivo using NIR fluorescent imaging. In our study, we further investigated whether a photosensitizer could be used as a tracer for metastatic lymph node mapping of pancreatic cancer based on previous reports. Compared to normal tissues, tumor tissues including primary tumors and metastatic lymph nodes had a higher uptake ability of deuteporfin (P < 0.05). Our research confirmed this targeting property of deuteporfin using in vivo fluorescent imaging. Consistent with observations from in vivo imaging experiments, frozen sections of metastatic lymph nodes intuitively displayed significantly higher and wider distributions of deuteporfin than normal sections.

A prospective pilot study of detection of sentinel lymph nodes in gynaecological cancers using a novel near infrared fluorescence imaging system

BACKGROUND

Sentinel Lymph Node (SLN) sampling may significantly reduce surgical morbidity by avoiding needless radical lymphadenectomy. In gynaecological cancers, the current practice in the UK is testing the accuracy of SLN detection using radioactive isotopes within the context of clinical trials. However, radioactive tracers pose significant logistic problems. We, therefore, conducted a pilot, observational study to assess the feasibility of a novel optical imaging device for SLN detection in gynaecological cancers using near infrared (NIR) fluorescence.

METHODS

A novel, custom-made, optical imaging system was developed to enable detection of multiple fluorescence dyes and allow simultaneous bright-field imaging during open surgery and laparoscopic procedures. We then evaluated the performance of the system in a prospective study of 49 women with early stage vulval, cervical and endometrial cancer who were scheduled to undergo complete lymphadenectomy. Clinically approved fluorescent contrast agents indocyanine green (ICG) and methylene blue (MB) were used. The main outcomes of the study included SLN mapping detection rates, false negative rates using the NIR fluorescence technique and safety of the procedures. We also examined the association between injection sites and differential lymphatic drainage in women with endometrial cancer by fluorescence imaging of ICG and MB.

RESULTS

A total of 64 SLNs were detected during both open surgery and laparoscopy. Following dose optimisation and the learning phase, SLN detection rate approached 100 % for all cancer types with no false negatives detected. Fluorescence from ICG and MB detected para-aortic SLNs in women with endometrial cancer following uterine injection. Percutaneous SLN detection was also achieved in most women with vulval cancer. No adverse reactions associated with the use of either dyes were observed.

CONCLUSIONS

This study demonstrated the successful clinical application of a novel NIR fluorescence imaging system for SLN detection across different gynaecological cancers. We showcased the first in human imaging, during the same procedure, of two fluorescence dyes in women with endometrial cancer.

A Comparison of Radiocolloid and Indocyanine Green Fluorescence Imaging, Sentinel Lymph Node Mapping in Patients with Cervical Cancer Undergoing Laparoscopic Surgery

Background and Purpose

⁹⁹TC combined with blue-dye mapping is considered the best sentinel lymph node (SLN) mapping technique in cervical cancer. Indocyanine green (ICG) with near infrared fluorescence imaging has been introduced as a new methodology for SLN mapping. The aim of this study was to compare these two techniques in the laparoscopic treatment of cervical cancer.

Methods

Medical records of patients undergoing laparoscopic SLN mapping for cervical cancer with either ⁹⁹Tc and patent blue dye (Group 1) or ICG (Group 2) from April 2008 until August 2012 were reviewed. Sensitivity, specificity, and overall and bilateral detection rates were calculated and compared.

Results

Fifty-eight patients were included in the study—36 patients in Group 1 and 22 patients in Group 2. Median tumor diameter was 25 and 29 mm, and mean SLN count was 2.1 and 3.7, for Groups 1 and 2, respectively. Mean non-SLN (NSLN) count was 39 for both groups. SLNs were ninefold more likely to be affected by metastatic disease compared with NSLNs (p < 0.005). Sensitivity and specificity were both 100 %. Overall detection rates were 83 and 95.5 % (p = nonsignificant), and bilateral detection rates were 61 and 95.5 % (p < 0.005), for Groups 1 and 2, respectively. In 75 % of cases, SLNs were located along the external or internal iliac nodal basins.

Conclusions

ICG SLN mapping in cervical cancer provides high overall and bilateral detection rates that compare favorably with the current standard of care.

A ratiometric threshold for determining presence of cancer during fluorescence-guided surgery

BACKGROUND AND OBJECTIVE

Fluorescence-guided imaging to assist in identification of malignant margins has the potential to dramatically improve oncologic surgery. However, a standardized method for quantitative assessment of disease-specific fluorescence has not been investigated. Introduced here is a ratiometric threshold derived from mean fluorescent tissue intensity that can be used to semi-quantitatively delineate tumor from normal tissue.

METHODS

Open-field and a closed-field imaging devices were used to quantify fluorescence in punch biopsy tissues sampled from primary tumors collected during a phase 1 trial evaluating the safety of cetuximab-IRDye800 in patients (n = 11) undergoing surgical intervention for head and neck cancer. Fluorescence ratios were calculated using mean fluorescence intensity (MFI) from punch biopsy normalized by MFI of patient-matched tissues. Ratios were compared to pathological assessment and a ratiometric threshold was established to predict presence of cancer.

RESULTS

During open-field imaging using an intraoperative device, the threshold for muscle normalized tumor fluorescence was found to be 2.7, which produced a sensitivity of 90.5% and specificity of 78.6% for delineating disease tissue. The skin-normalized threshold generated greater sensitivity (92.9%) and specificity (81.0%).

CONCLUSION

Successful implementation of a semi-quantitative threshold can provide a scientific methodology for delineating disease from normal tissue during fluorescence-guided resection of cancer.

Evaluation of a radioactive and fluorescent hybrid tracer for sentinel lymph node biopsy in head and neck malignancies: prospective randomized clinical trial to compare ICG-(99m)Tc-nanocolloid hybrid tracer versus (99m)Tc-nanocolloid

PURPOSE

There is some controversy about the value of sentinel lymph node excision (SLNE) in patients with head and neck malignancies. The gold standard for detection and targeted extirpation of the SLN is lymphoscintigraphy with (99m)Tc-nanocolloid. The purpose of this prospective randomized study was to analyse the feasibility and clinical benefit of a hybrid tracer comprising the near-infrared (NIR) fluorescent indocyanine green (ICG) and (99m)Tc-nanocolloid (ICG-(99m)Tc-nanocolloid) in direct comparison with standard (99m)Tc-nanocolloid for guiding SLNE in patients with head and neck cutaneous malignancies.

METHODS

We analysed the data from 40 clinically lymph node-negative patients with melanoma, high-risk cutaneous squamous cell carcinoma, Merkel cell carcinoma or sweat gland carcinoma who underwent SLNE with ICG-(99m)Tc-nanocolloid (cohort A) or with the standard (99m)Tc-nanocolloid (cohort B).

RESULTS

Overall SLNs were identified preoperatively in all 20 patients (100%) in cohort A and in 18 of 20 patients (90%) in cohort B. The SLN basin was detected preoperatively in 18 patients (90%) in cohort A and also in 18 patients (90%) in cohort B. SLNs were identified intraoperatively in all 20 patients (100%) in cohort A and in 19 patients (95%) in cohort B (p = 0.487). Metastatic SLNs were detected in 9 patients (22.5%), 3 (15.0%) in cohort A and 6 (30.0%) in cohort B (p = 0.228).

CONCLUSION

The hybrid tracer ICG-(99m)Tc-nanocolloid is an innovative imaging tracer, reliably and readily providing additional information for the detection and excision of SLN in the head and neck region. Therefore, SLNE with combined radioactive and NIR fluorescence guidance is an attractive option for improving the SLN detection rate in patients with cutaneous head and neck malignancies.

Sentinel Lymph Node Mapping of Liver

BACKGROUND

Although the sentinel lymph node (SLN) hypothesis has been applied to many tissues and organs, liver has remained unstudied. Currently, it is unclear whether hepatic SLNs even exist. If so, they could alter the management of intrahepatic cholangiocarcinoma and other hepatic malignancies by minimizing the extent of surgery while still providing precise nodal staging. This study investigated whether invisible yet tissue-penetrating near-infrared (NIR) fluorescent light can provide simultaneous identification of both the SLN and all other regional lymph nodes (RLNs) in the liver.

METHODS

In 25 Yorkshire pigs, this study determined whether SLNs exist in liver and compared the effectiveness of two clinically available NIR fluorophores [methylene blue and indocyanine green (ICG)], and two novel NIR fluorophores previously described by our group (ESNF14 and ZW800-3C) for SLN and RLN mapping.

RESULTS

In this study, ESNF14 showed the highest signal-to-background ratio and the longest retention time in SLNs without leakage to second-tier lymph nodes. The findings showed that ICG had apparent leakage to second-tier nodes, and ZW800-3C had poor migration after intraparenchymal injection. However, when injected intravenously, ZW800-3C was able to highlight all RLNs in liver during a 4- to 6-h period. Simultaneous dual-channel imaging of SLN (ESNF14) and RLN (ZW800-3C) permitted unambiguous identification and image-guided resection of SLNs and RLNs in liver.

CONCLUSION

The NIR imaging technology enables real-time intraoperative identification of SLNs and RLNs in the liver of swine. If these results are confirmed in patients, new strategies for the surgical management of intrahepatic malignancies should be possible.

A review of performance of near-infrared fluorescence imaging devices used in clinical studies

Near-infrared fluorescence (NIRF) molecular imaging holds great promise as a new "point-of-care" medical imaging modality that can potentially provide the sensitivity of nuclear medicine techniques, but without the radioactivity that can otherwise place limitations of usage. Recently, NIRF imaging devices of a variety of designs have emerged in the market and in investigational clinical studies using indocyanine green (ICG) as a non-targeting NIRF contrast agent to demark the blood and lymphatic vasculatures both non-invasively and intraoperatively. Approved in the USA since 1956 for intravenous administration, ICG has been more recently used off label in intradermal or subcutaneous administrations for fluorescence imaging of the lymphatic vasculature and lymph nodes. Herein, we summarize the devices of a variety of designs, summarize their performance in lymphatic imaging in a tabular format and comment on necessary efforts to develop standards for device performance to compare and use these emerging devices in future, NIRF molecular imaging studies.

The status of contemporary image-guided modalities in oncologic surgery

OBJECTIVE

To review the current trends in optical imaging to guide oncologic surgery.

BACKGROUND

Surgical resection remains the cornerstone of therapy for patients with early stage solid malignancies and more than half of all patients with cancer undergo surgery each year. The technical ability of the surgeon to obtain clear surgical margins at the initial resection remains crucial to improve overall survival and long-term morbidity. Current resection techniques are largely based on subjective and subtle changes associated with tissue distortion by invasive cancer. As a result, positive surgical margins occur in a significant portion of tumor resections, which is directly correlated with a poor outcome.

METHODS

A comprehensive review of studies evaluating optical imaging techniques is performed.

RESULTS

A variety of cancer imaging techniques have been adapted or developed for intraoperative surgical guidance that have been shown to improve functional and oncologic outcomes in randomized clinical trials. There are also a large number of novel, cancer-specific contrast agents that are in early stage clinical trials and preclinical development that demonstrate significant promise to improve real-time detection of subclinical cancer in the operative setting.

CONCLUSIONS

There has been an explosion of intraoperative imaging techniques that will become more widespread in the next decade.