Comparative aspects of targeted sentinel lymph node mapping in veterinary and human medicine: opportunities for future research

There is a significant overlap in the genetic, metabolic and epigenetic alterations between human and companion animal cancers, including those of the oral cavity, breast, bladder, skin, lungs and pancreas. In many cancer types, the identification and removal of affected lymph nodes are essential for accurate cancer management, including treatment and prognosis. Historically, lymphadenectomy and subsequent radical resection based on regional anatomy, palpation and lymph node aspirates were considered sufficient; however, modern approaches with sentinel lymph node mapping (SLN) mapping have increased the accuracy of surgical decision-making. Preoperative and intraoperative SLN mapping techniques in veterinary patients parallel those used in human medicine. While many of these techniques are highly successful, the main challenges with current methodologies are their sensitivity and specificity for the presence of cancer, which can be overcome via precision medicine and targeted SLN mapping agents. Given the large population of dogs and cats with cancer, the crossover of knowledge between species can help to deepen our understanding of many of these cancers and can be useful in evaluating new drugs and/or therapies. In this review, we discuss SLN mapping techniques in veterinary medicine and the concept of precision medicine as it relates to targeted SLN mapping imaging agents. The large number of companion animals affected by cancer is an underutilized resource to bridge the translational gap and we aim to provide a reference for the use of dogs and cats as a comparative model for human SLN mapping.

The Use of Sentinel Lymph Node Mapping for Canine Mast Cell Tumors

Cancer is the leading cause of death in companion animals. The evaluation of locoregional lymph nodes, known as lymph node mapping, is a critical process in assessing the stage of various solid tumors, such as mast cell tumors (MCTs), anal gland anal sac adenocarcinoma, melanoma, and mammary gland adenocarcinoma. MCTs are among the most prevalent skin malignancies in dogs. Staging is used to describe the extent of neoplastic disease, provide a framework for rational treatment planning, and evaluate treatment results. The aim of this review is to present the current knowledge on sentinel lymph node (SLN) mapping in canine MCTs, its influence on treatment decisions and prognosis, as well as the advantages and limitations of different SLN techniques currently available in veterinary oncology. A search methodology was adopted using the PubMed, Scopus, and Google Scholar databases. Critical analyses of up-to-date research have shown that lymphoscintigraphy can achieve a lymph node detection rate of between 91 and 100%. This method is becoming increasingly recognized as the gold standard in both human and veterinary medicine. In addition, initial studies on a limited number of animals have shown that computed tomographic lymphography (CTL) is highly effective in the SLN mapping of MCTs, with detection rates between 90 and 100%. The first study on contrast-enhanced ultrasound (CEUS) also revealed that this advanced technique has up to a 95% detection rate in canine MCTs. These methods provide non-ionizing alternatives with high detection capabilities. Furthermore, combining computed tomography and near-infrared fluorescence (NIR/NIR-LND) lymphography is promising as each technique identifies different SLNs. Indirect lymphography with Lipiodol or Iohexol is technically feasible and may be also used to effectively detect SLNs. The integration of these mapping techniques into routine MCT staging is essential for enhancing the precision of MCT staging and potentially improving therapeutic outcomes. However, further clinical trials involving a larger number of animals are necessary to refine these procedures and fully evaluate the clinical benefits of each technique.

Visualization Methods for Uterine Sentinel Lymph Nodes in Early-Stage Endometrial Carcinoma: A Comparative Analysis

BACKGROUND

Sentinel lymph node (SLN) biopsy in early-stage endometrial cancer is recommended over systematic lymphadenectomy due to reduced morbidity and comparable detection rates. The main objective of this study was to compare the overall and bilateral detection rates of SLN in early-stage endometrial cancer using three techniques.

METHODS

a prospective cohort study was designed to detect the difference in SLN detection rate in three cohorts: Indocyanine green (ICG), methylene blue (MB), and tracer combination (ICG + MB). Mapping characteristics, detection rate, number of SLNs, and positive SLNs of the three cohorts were compared.

RESULTS

A total of 99 patients were enrolled. A total of 109 SLN sites with 164 lymph nodes were detected. No differences were found between the three cohorts in terms of age, BMI, tumor diameter, or other histologic characteristics. The overall SLN detection rate (DR) was 54.3% in the MB group, 72.7% in ICG, and 80.6% in the ICG-MB group. Bilateral DR was 22.9%, 39.4%, and 54.8% in groups, respectively, with the MB method yielding significantly inferior results.

CONCLUSIONS

The ICG-MB group demonstrated superior overall and bilateral detection rates, but a significant difference was found only in the MB cohort. Combining tracer agents can enhance the accuracy of SLN identification in initial-stage endometrial cancer without additional risk to the patient.

Real-World Data Assessing the Impact of Lymphovascular Space Invasion on the Diagnostic Performance of Sentinel Lymph Node Mapping in Endometrial Cancer

BACKGROUND

SLN mapping has emerged as a standard of care in endometrial cancer due to its high sensitivity and significant reduction in morbidity. Although lymphovascular space invasion (LVSI) is a known risk factor for lymph node metastasis and recurrence, evidence on the reliability of SLN mapping in LVSI-positive patients is scarce. The aim of this study was to determine the impact of LVSI on the diagnostic performance of SLN mapping.

METHODS

This retrospective cohort study included patients with endometrial cancer who underwent primary surgical treatment at the Bern University Hospital, Switzerland, between 2012 and 2022.

RESULTS

LVSI was present in 22% of patients and was significantly associated with lymph node metastasis (p < 0.001) and recurrence (p < 0.001). In node-negative patients with only SLN mapping performed, LVSI was an independent predictor of recurrence during multivariable Cox regression analysis (p = 0.036). The negative predictive value of SLN mapping was 91.5% and was significantly lower in tumors with LVSI (75.0%) compared to LVSI-negative tumors (95.6%, p = 0.004).

CONCLUSION

The presence of LVSI was significantly associated with worse oncological outcomes. LVSI was an independent predictor of recurrence in node-negative patients with only SLN mapping performed. Furthermore, the negative predictive value of SLN mapping was significantly lower in LVSI-positive tumors.

Comparing carbon nanoparticles and indocyanine green for sentinel lymph node mapping in endometrial cancer: A randomized-controlled single-center trial

BACKGROUND AND OBJECTIVES

To compare the feasibility and diagnostic value of sentinel lymph node (SLN) mapping with carbon nanoparticles (CNPs) and indocyanine green (ICG) in endometrial cancer (EC).

METHODS

This was a single-center, open-label, randomized controlled trial. Between August 1, 2020 and April 30, 2022, patients with early-stage EC were assessed for enrollment. All patients underwent SLN mapping with ICG or CNPs ± pelvic and/or para-aortic lymphadenectomy. The detection rate (DR), its impact factors, the sensitivity and the negative predictive value (NPV) of SLN mapping were analyzed.

RESULTS

In total, 206 patients, with 103 per group, were included. The overall and bilateral DRs of the two groups were comparable without significant differences. There was no difference regarding the distribution of mapped SLNs. The sensitivity was 66.7% for both groups, and the NPVs were not significantly different. Furthermore, the sensitivity and NPV reached 100% when calculated either per hemipelvis or only in patients with bilateral SLN detection.

CONCLUSIONS

SLN mapping by CNPs in EC is feasible with high DRs and diagnostic accuracy compared with ICG. CNPs might be an alternative to ICG for SLN mapping when near-infrared imaging equipment is lacking, especially in stage IA patients.

Application of sentinel lymph node mapping in endometrial cancer: A survey among Chinese gynecological oncologists

AIM

To gain a better understanding of the use of sentinel lymph node mapping by Chinese oncologists for endometrial cancer staging and analyze factors influencing its application.

METHODS

Questionnaires were collected online before and by phone after the symposium to evaluate the general characteristics of oncologists who participated in the endometrial cancer seminar and factors associated with the application of sentinel lymph node mapping in endometrial cancer patients.

RESULTS

Gynecologic oncologists from 142 medical centers participated in the survey. 35.4% of doctors employed sentinel lymph node mapping for endometrial cancer staging, 57.3% chose indocyanine green as the tracer. Multivariate analysis revealed that cancer research center (odds ratio = 4.229, 95% CI 1.747-10.237), physician familiarity with sentinel lymph node mapping (odds ratio = 126.188, 95% confidence interval 43.220-368.425) and the use of ultrastaging (odds ratio = 2.657, 95% confidence interval 1.085-6.506) were related to the doctors' selection of sentinel lymph node mapping. There was a significant difference in the surgical procedure for early endometrial cancer, the number of removed sentinel lymph node, and the reason for not adopting sentinel lymph node mapping before and after the symposium.

CONCLUSIONS

The theoretical knowledge of sentinel lymph node mapping, the use of ultrastaging, and cancer research center are related to a higher acceptance of sentinel lymph node mapping. Distance learning is conducive to the promotion of this technology.

Feasibility of Sentinel Lymph Node Mapping With Carbon Nanoparticles in Cervical Cancer: A Retrospective Study

INTRODUCTION

This retrospective study aims to investigate the feasibility of using carbon nanoparticles to detect sentinel lymph nodes (SLNs) in cervical cancer.

METHODS

This study involved 174 patients with cervical cancer. Cervix tissues adjacent to the cancer were injected with 1 mL of carbon nanoparticles (CNPs) at the 3 and 9 o'clock positions according to the instructions. The pelvic lymph nodes were then dissected, and the black-stained sentinel lymph nodes were sectioned for pathological examination.

RESULTS

Of 174 cases, 88.5% of patients (154/174) had at least 1 sentinel lymph node, and 131 patients (75.29%) had bilateral pelvic sentinel lymph nodes. The left pelvic lymph node was the most common sentinel lymph node (34.16%). At least 1 sentinel lymph node was observed in 285 out of 348 hemipelvises, with a detection rate of a side-specific sentinel lymph node of 81.89%. In total, 47 hemipelvises had metastasis of the lymph node, and 33 involved the sentinel lymph node, with a sensitivity of 70.21% and a false-negative rate of 29.79%. There were 238 hemipelvises with no metastasis of the lymph node, as well as negative sentinel lymph nodes, with a specificity of 100% and a negative predictive value of 94.44%. The univariate analysis demonstrated that risk factors included tumor size (OR .598, 95% CI: .369-.970) and deep stromal invasion (OR .381, 95% CI: .187-.779). The deep stromal invasion was the only variable for the false-negative detection of a sentinel lymph node.

CONCLUSION

Sentinel lymph node mapping with carbon nanoparticles might be applied to predict the metastasis of pelvic lymph nodes in cervical cancer. However, tumor size and deep stromal invasion might negative influence the detection rate of SLN.

Sentinel Lymph Node Mapping in Presumed Low- and Intermediate-Risk Endometrial Cancer Management (SLIM): A Multicenter, Prospective Cohort Study in The Netherlands

The aim was to investigate the incidence of sentinel lymph node (SLN) metastases and the contribution of SLN mapping in presumed low- and intermediate-risk endometrial cancer (EC). A multicenter, prospective cohort study in presumed low- and intermediate-risk EC patients was performed. Patients underwent SLN mapping using cervical injections of indocyanine green and a minimally invasive hysterectomy with bilateral salpingo-oophorectomy. The primary outcome was the incidence of SLN metastases, leading to adjusted adjuvant treatment. Secondary outcomes were the SLN detection rate and the occurrence of complications. Descriptive statistics and univariate general linear model analyses were used. A total of 152 patients were enrolled, with overall and bilateral SLN detection rates of 91% and 61%, respectively. At final histology, 78.9% of patients (n = 120) had truly low- and intermediate-risk EC. Macro- and micro-metastases were present in 11.2% (n = 17/152), and three patients had isolated tumor cells (2.0%). Nine patients (5.9%) had addition of adjuvant radiotherapy based on SLN metastases only. In 2.0% of patients with high-risk disease, adjuvant therapy was more limited due to negative SLNs. This study emphasizes the importance of SLN mapping in presumed early-stage, grade 1 and 2 EC, leading to individualized adjuvant management, resulting in less undertreatment and overtreatment.

Retrospective Cohort Study on the Longterm Oncologic Outcomes of Sentinel Lymph Node Mapping Methods (Dye-Only Versus Dye and Radioisotope Mapping) in Early Breast Cancer: A Propensity Score-Matched Analysis

Purpose

In sentinel lymph node (SLN) biopsy (SLNB) during breast cancer surgery, SLN mapping using dye and isotope (DUAL) may have lower false-negative rates than the dye-only (DYE) method. However, the longterm outcomes of either method are unclear. We aimed to compare longterm oncological outcomes of DYE and DUAL for SLNB in early breast cancer.

Materials and Methods

This retrospective single-institution cohort study included 5,795 patients (DYE, 2,323; DUAL, 3,472) with clinically node-negative breast cancer who underwent SLNB and no neoadjuvant therapy. Indigo carmine was used for the dye method and Tc99m-antimony trisulfate for the isotope. To compare longterm outcomes, pathologic N0 patients were selected from both groups, and propensity score matching (PSM), considering age, pT stage, breast surgery, and adjuvant treatment, was performed (1,441 patients in each group).

Results

The median follow-up duration was 8.7 years. The median number of harvested sentinel nodes was 3.21 and 3.12 in the DYE and DUAL groups, respectively (p=0.112). The lymph node-positive rate was not significantly different between the two groups in subgroups of similar tumor sizes (p>0.05). Multivariate logistic regression revealed that the mapping method was not significantly associated with the lymph node-positive rate (p=0.758). After PSM, the 5-year axillary recurrence rate (DYE 0.8% vs. DUAL 0.6%; p=0.096), and 5-year disease-free survival (DYE 93.9% vs. DUAL 93.7%; p=0.402) were similar between the two groups.

Conclusion

Dye alone for SLNB was not inferior to dual mapping regarding longterm oncological outcomes in early breast cancer.

Decoupling channel count from field of view and spatial resolution in single-sensor imaging systems for fluorescence image-guided surgery

SIGNIFICANCE

Near-infrared fluorescence image-guided surgery is often thought of as a spectral imaging problem where the channel count is the critical parameter, but it should also be thought of as a multiscale imaging problem where the field of view and spatial resolution are similarly important.

AIM

Conventional imaging systems based on division-of-focal-plane architectures suffer from a strict relationship between the channel count on one hand and the field of view and spatial resolution on the other, but bioinspired imaging systems that combine stacked photodiode image sensors and long-pass/short-pass filter arrays offer a weaker tradeoff.

APPROACH

In this paper, we explore how the relevant changes to the image sensor and associated image processing routines affect image fidelity during image-guided surgeries for tumor removal in an animal model of breast cancer and nodal mapping in women with breast cancer.

RESULTS

We demonstrate that a transition from a conventional imaging system to a bioinspired one, along with optimization of the image processing routines, yields improvements in multiple measures of spectral and textural rendition relevant to surgical decision-making.

CONCLUSIONS

These results call for a critical examination of the devices and algorithms that underpin image-guided surgery to ensure that surgeons receive high-quality guidance and patients receive high-quality outcomes as these technologies enter clinical practice.

Uptake and outcomes of sentinel lymph node mapping in women undergoing minimally invasive surgery for endometrial cancer

OBJECTIVE

To examine the patterns and outcomes of sentinel lymph node (SLN) assessment in women with endometrial cancer.

DESIGN

Retrospective cohort study.

SETTING

United States inpatient and outpatient hospital services.

POPULATION

Women with endometrial cancer who underwent a laparoscopic or robotic-assisted hysterectomy.

METHODS

The Perspective Database from 2012 to 2018 was used. Performance of lymph node dissection was classified as SLN mapping, lymph node dissection or no nodal evaluation. Adjusted regression models were developed to examine the association between SLN mapping and morbidity and cost.

MAIN OUTCOME MEASURES

Utilisation rates, morbidity and cost of both lymph node dissection and SLN mapping.

RESULTS

Among 45 381 patients, SLN mapping was performed for 7768 patients (17.1%), lymph node dissection was performed for 23 214 patients (51.2%) and no lymphatic evaluation was performed for 14 399 patients (31.7%). SLN mapping increased from 1.8% in 2012 to 35.3% in 2018, whereas the rate of lymph node dissection decreased from 63.5% to 39.1% (p < 0.001). Among women who underwent nodal evaluation, residence in the west, White race and use of robotic-assisted hysterectomy were associated with SLN mapping (p < 0.05 for all). The complication rate was 5.9% for SLN mapping, compared with 7.3% in those that underwent lymph node dissection (aRR 0.85, 95% CI 0.77-0.95). The median hospital costs for women who underwent SLN mapping ($10 479) and lymph node dissection ($10 747) were higher than for those who did not undergo nodal assessment ($9149) (p < 0.001).

CONCLUSIONS

The performance of SLN mapping is increasing for endometrial cancer. Compared with lymph node dissection, SLN mapping is associated with lower morbidity. SLN mapping significantly increases the costs compared with hysterectomy alone.

TWEETABLE ABSTRACT

SLN mapping is increasing rapidly for endometrial cancer and is associated with decreased perioperative morbidity.

Quantitative and Semi-quantitative Methods for Assessing the Degree of Methylene Blue Staining in Sentinel Lymph Nodes in Dogs

Background: To develop a digital algorithm for quantitative assessment of surface methylene blue staining in whole lymph nodes and validate a semi-quantitative visual scoring method for patient-side use.

Methods: Lymph nodes from canine patients with spontaneous tumors undergoing sentinel lymph node mapping were prospectively assessed ex vivo and photographed. Using an open-source computer-based imaging software, an algorithm was developed for quantification of staining based on a signal-to-background ratio. Next, two blinded observers evaluated images and assigned a semi-quantitative visual score based on surface staining (0—no blue stain, 1−1–50% stained, and 2−51–100% stained) and those results were compared to the established quantitative standard.

Results: Forty-three lymph nodes were included. Image analysis successfully quantified blue staining and differentiated from normal lymph node tissue in all cases. Agreement between observers using the Kappa coefficient demonstrated strong agreement (k = 0.8581, p < 0.0001) between semi-quantitative visual scoring and image analysis. There was substantial interobserver and intraobserver agreement for the scoring system (k = 0.7340, p < 0.0001 and k = 0.8983, p < 0.0001, respectively).

Conclusion: A digital algorithm using an open-source software was simple and straightforward to use for quantification of blue staining. The use of a semi-quantitative visual scoring system shows promise for a simple, objective, repeatable assessment of methylene blue staining at the time of surgery. This study demonstrates reliable and repeatable methods for blue staining quantification thereby providing a novel and objective reporting mechanism in scientific research involving sentinel lymph node mapping.

Efficacy of sentinel lymph node mapping in endometrial cancer with low- or high-intermediate risk

BACKGROUND AND OBJECTIVES

This study was aimed to evaluate the efficacy of sentinel lymph node (SLN) mapping using indocyanine green (ICG) in Chinese women with endometrial cancer (EC).

METHODS

Consecutive EC patients undergoing SLN mapping at Obstetrics and Gynecology Hospital of Fudan University were retrospectively reviewed. Overall and bilateral SLN detection rates and SLN locations were presented. Sensitivity, negative predictive value (NPV), and agreement rate were calculated and were compared between patients with low-intermediate (LIR) or high-intermediate risk (HIR).

RESULTS

There were 454 patients screened, with SLN mapping with ICG performed in 428 patients and systematic lymphadenectomy performed in 159 patients. Overall and bilateral SLN detection rates were 96.50% and 82.71%, respectively. The sensitivity of SLN mapping was 80.00%, and the NPV was 97.76%. SLNs were most commonly located in obturator and external iliac regions. Efficacy of SLN mapping was higher in LIR patients than in HIR patients, with sensitivities of 100.00% and 75.00% (p > 0.05), NPVs of 100.00% and 90.00% (p = 0.002), and agreement rates of 100.00% and 92.31% (p = 0.007), respectively.

CONCLUSION

SLN mapping with ICG had acceptable diagnostic efficacy in Chinese women with EC, but may cause more missed diagnoses in patients with HIR due to relatively low NPV and agreement rate.

The efficiency of a combined injection technique for sentinel lymph node mapping in intermediate-high-risk endometrial cancer

BACKGROUND AND OBJECTIVES

Sentinel lymph node (SLN) mapping was considered for treating endometrial cancer (EC) which was apparent confined to the uterus. Nevertheless, intermediate-high-risk EC patients have super high risk to undergo isolated para-aortic lymph node metastases comparing with low-risk patients. Therefore, this investigation aimed to compare the efficacy of two SLN methods in detecting para-aortic lymph node metastases.

METHODS

According to SLN mapping injection methods, intermediate-high-risk EC patients who received both SLN mapping and systematic lymphadenectomy were divided into the combined group (fundal and cervical injections) and the cervical group (cervical injection only).

RESULTS

The para-aortic SLN detection rate in the combined group (40.4%) was higher than that in the cervical group (4.4%) with p < 0.001. While the differences concerning the sensitivity, false-negative rate, and negative predictive value between the two groups were not significant. The survival outcomes of patients were comparable between the two groups.

CONCLUSION

Our data showcased that the combined (fundal and cervical) injection had a higher detection rate of para-aortic SLNs than cervical injection only. The efficiency of SLN mapping and the survival outcomes were not significantly different between the two groups. Further investigations are warranted to assess the value of combined injection regarding SLN technique.

Sentinel Lymph Node Mapping in Endometrial Cancer: A Comprehensive Review

Endometrial cancer (EC) is known as a common gynecological malignancy. The incidence rate is on the increase annually. Lymph node status plays a crucial role in evaluating the prognosis and selecting adjuvant therapy. Currently, the patients with high-risk (not comply with any of the following: (1) well-differentiated or moderately differentiated, pathological grade G1 or G2; (2) myometrial invasion< 1/2; (3) tumor diameter < 2 cm are commonly recommended for a systematic lymphadenectomy (LAD). However, conventional LAD shows high complication incidence and uncertain survival benefits. Sentinel lymph node (SLN) refers to the first lymph node that is passed by the lymphatic metastasis of the primary malignant tumor through the regional lymphatic drainage pathway and can indicate the involvement of lymph nodes across the drainage area. Mounting evidence has demonstrated a high detection rate (DR), sensitivity, and negative predictive value (NPV) in patients with early-stage lower risk EC using sentinel lymph node mapping (SLNM) with pathologic ultra-staging. Meanwhile, SLNM did not compromise the patient’s progression-free survival (PFS) and overall survival (OS) with low operative complications. However, the application of SLNM in early-stage high-risk EC patients remains controversial. As revealed by the recent studies, SLNM may also be feasible, effective, and safe in high-risk patients. This review aims at making a systematic description of the progress made in the application of SLNM in the treatment of EC and the relevant controversies, including the application of SLNM in high-risk patients.

From systematic lymphadenectomy to sentinel lymph node mapping: a review on transitions and current practices in endometrial cancer staging

Endometrial cancer care has undergone major changes in the past 30 years. In 1988, staging transitioned from clinical to surgical. Moreover, the surgical approach of choice is no longer open surgery, but minimally invasive surgery. An improvement in terms of nodal evaluation followed. Full systematic lymphadenectomy has been continuously replaced by sentinel lymph node mapping. Although sentinel lymph node mapping with a cervical injection of indocyanine green dye is rapidly gaining clinical acceptance, we lack consistent recommendations on a well-defined procedure that accurately and indolently assesses the lymph node status. Such recommendations are indispensable, as nodal status is the most important predictive factor of survival and is essential for tailoring adjuvant treatment to the risk of recurrence. This paper focuses on transitions in endometrial cancer care and highlights current data on sentinel lymph node mapping in endometrial cancer. We demonstrate that sentinel lymph node mapping is a safe and accurate strategy for nodal status evaluation with appropriate sensitivity, false-negative rate and negative predictive value in high- as well as low-risk settings. Furthermore, we elaborate on type and dose of tracer, site of injection, number of sentinel lymph nodes to be removed, sentinel lymph node mapping learning curve, operation mode and sentinel lymph node ultrastaging. In the future, guidelines with consistent recommendations on the above outlined features of sentinel lymph node mapping should be established to allow for a uniform and wide-spread application of the sentinel lymph node mapping procedure.

Lymphadenectomy in endometrial cancer - achieving more with less?

The lymph node status of patients with endometrial cancer is known to be a crucial determinant for the prognosis of the disease. It also provides the indication for further adjuvant treatment. The staging of endometrial cancer by surgery has been a controversial issue for more than 30 years. The significant complication rate after lymphadenectomy and the development of minimally invasive surgery have led to the use of sentinel lymph node (SLN) mapping. In the present review, we present the development of surgical staging procedures in patients with endometrial cancer and summarize the recently expanding body of published literature on the subject. SLN mapping is a safe and accurate technique, especially when indocyanine green is used as a tracer. SLN mapping appears to reduce complication rates as well as costs without affecting the oncologic outcome. Large prospective studies are needed to establish the effects of SLN mapping on the outcome of disease, especially in high-risk patients with endometrial cancer. Furthermore, the need for additional systematic lymphadenectomy prior to adjuvant radio-chemotherapy in patients diagnosed with isolated lymph node metastasis during SLN biopsy must be investigated further. This might pave the way for a new surgical approach in patients with endometrial cancer.

Challenges Posed by Embryonic and Anatomical Factors in Systematic Lymphadenectomy for Endometrial Cancer

Lymph node involvement has been shown to be one of the most relevant prognostic factors in a variety of malignancies; this is also true of endometrial cancer. The determination of the lymph node status is crucial in order to establish the tumor stage, and to consider adjuvant treatment. A wide range of surgical staging practices are currently used for the treatment of endometrial cancer. The necessity and extent of lymph node dissection is an ongoing controversial issue in gynecological oncology. Lymph node surgery in endometrial cancer is technically challenging, and can be time consuming because of the topographic complexity of lymphatic drainage as such, and the fact that the lymph nodes are directly adjacent to both blood vessels and nerves. Therefore, profound and exact knowledge of the anatomy is essential. Sentinel lymph node mapping was recently introduced in surgical staging with the aim of reducing morbidity, whilst also obtaining useful prognostic information from a patient’s lymph node status. The present review summarizes the current evidence on the role of lymph node surgery in endometrial cancer, focusing on the embryological, anatomical, and technical aspects.

Usefulness of sentinel lymph node mapping using indocyanine green and fluorescent imaging in the diagnosis of lymph node metastasis in endometrial cancer

The lymph node status is the most important prognostic factor for endometrial cancer. This study aimed to assess whether sentinel lymph node mapping (SLNM) is applicable in endometrial cancer. A retrospective review of patients with endometrial cancer who were diagnosed and treated in Asan Medical Centre from September 2015 to December 2017 was conducted. One hundred patients underwent robotic (da Vinci®) or laparoscopic surgical treatment, including SLNM with indocyanine green (ICG) fluorescence detection using the Firefly® and NIR/ICG systems. At least one lymph node area was observed in 100% of SLNM cases. Sentinel node detection and frozen biopsy were performed in all cases, and all patients with metastasis were found on SLNM. The sensitivity and negative predictive value were both 100% in the patient-by-patient and station-by-station analyses. SLNM appears to be a feasible method to reduce the morbidity and increase the detection rate in early-stage endometrial carcinoma.What is already known on this subject? There are studies that it is safe to diagnose the possibility of lymph node metastasis through sentinel lymph node mapping in endometrial cancer.What do the results of this study add? In this study, it is shown that the accuracy of sentinel lymph node mapping is 100% accurate.What are the implications of these findings for clinical practise and/or further research? Therefore, total lymphadenectomy will not be necessary for the future.

Upstaging nodal status in colorectal cancer using ex vivo fluorescence sentinel lymph node mapping: preliminary results

BACKGROUND

Sentinel lymph node (SLN) mapping using near-infrared fluorescence (NIRF) imaging is a recent technique to improve nodal staging in several tumors. The presence of colorectal cancer (CRC) micro-metastases has recently been defined as N1 disease and no longer as N1mi, determining the need for adjuvant chemotherapy. In CRC, the reported rate of SLN micro-metastases detected by ultrastaging techniques is as high as 30%. The aim of this prospective study is to report the preliminary results of the sensitivity analysis of NIRF imaging for ex vivo SLN mapping and the research of micro-metastases in CRC, in patients with node-negative disease (NND).

MATERIAL AND METHODS

On the specimen of 22 CRC patients, 1 mL of ICG (5 mg/mL) was injected submucosally around the tumor to identify SLNs. NND SLNs were further investigated with ultrastaging techniques.

RESULTS

Three-hundred and sixty-three lymph nodes were retrieved (59 SLNs; mean per case: 2.7). The detection, sensitivity and false-negative rate were 100%, 100% and 0% respectively. Ultrastaging investigations showed no micro-metastases in the NND SLNs.

CONCLUSIONS

The ex vivo SLN fluorescence-based detection in CRC was confirmed to be easy to perform and reliable. In this preliminary results report of an ongoing study, the SLN assay was congruent with the nodal status, as confirmed by histological investigations.

The current clinical approach to newly diagnosed uterine cancer

INTRODUCTION

Uterine cancer is the most common gynecologic malignancy, although fortunately, 75% of women present with early-stage disease. A major area of controversy regarding the management of the disease concerns postoperative therapy for both women with early- and advanced-stage endometrial carcinoma. Here, we review landmark evidence that can help guide clinical decision-making in the treatment of women diagnosed with endometrial cancer.

AREAS COVERED

In this review, we present the latest data driving decisions for both surgical management and postoperative therapy for women with endometrial carcinoma. Areas discussed include surgical staging, with a specific discussion on the role of sentinel lymph node mapping, and postoperative therapy, ranging from the data supporting observation for women with early-stage, low-risk disease to combination therapy for women with advanced disease. Less common histologies, such as serous and clear cell carcinoma, as well as carcinosarcoma, will also be covered. Furthermore, a section of the paper is dedicated to the current state of fertility-sparing surgery.

EXPERT OPINION

We suggest several approaches for deciding on adjuvant therapy, based on stage and histology, after comprehensive surgical staging. The role that endometrial cancer molecular subtypes will play on postoperative therapy remains to be fully investigated.

Failure of sentinel lymph node mapping in a patient with endometrial cancer with chronic lymphocytic leukemia: A case report

We aimed to report a detection failure of sentinel lymph node (SLN) mapping via indocyanine green in a patient with endometrial cancer with a previous history of chronic lymphocytic leukemia (CLL), which is a potential risk factor to obstruct lymphatic channels. A 64-year-old woman with a 12-year history of CLL presented to the clinic with grade 2 endometrioid carcinoma. The patient underwent laparoscopic surgical staging. Indocyanine green was used intraoperatively to locate the SLN. No lymph node or lymphatic vessels were identified during SLN mapping. At the final pathology, the morphological findings of CLL were detected in the lymph nodes without metastasis of endometrial cancer. Sentinel lymph node mapping failure due to obstruction of lymphatic channels in a patient with CLL was demonstrated in this study. This is the first report to the best of our knowledge showing SLN mapping failure in the presence of lymphoproliferative diseases.

Sentinel Pelvic Lymph Node Dissection by Natural Orifices Transvaginal Endoscopic Surgery Approach after Indocyanine Green Dye Detection in Early Endometrial Cancer of Posthysterectomy Patient

There was a case of 57-year-old female who was done the natural orifices transvaginal endoscopic surgery (NOTES) hysterectomy and bilateral salpingo-oophorectomy for benign disease. However, her biopsy result was Grade 1 endometrioid adenocarcinoma, and she was incidentally diagnosed as endometrial cancer. She was uneventful apart from that finding. She underwent the sentinel pelvic lymph node dissection with indocyanine green-guided NOTES approach for complete staging. This technique may be helpful to maximize the complete staging in early endometrial cancer as well as it can minimize the morbidity-related lymphadenectomy. In conclusion, in spite of a new technique for NOTEs, it can be safe and cost-effective for patients.

Triple tracer (blue dye, indocyanine green, and Tc99) compared to double tracer (indocyanine green and Tc99) for sentinel lymph node detection in endometrial cancer: a prospective study with random assignment

OBJECTIVE

Sentinel lymph node (SLN) mapping is increasingly being used in the treatment of apparent early-stage endometrial cancer. The aim of this study was to evaluate whether three tracers (blue dye, indocyanine green (ICG), and technetium-99 (Tc99)) performed better than two (ICG and Tc99).

STUDY DESIGN

Prospective study of all consecutive patients (n=163) diagnosed with clinical early-stage endometrial cancer from 2015 to 2017. All patients were randomly assigned to receive a mixture of ICG and Tc99 with or without blue dye. Subgroup analysis for detection rates was performed for each group (double versus triple tracer).

RESULTS

One hundred and fifty-seven patients met the inclusion criteria. Eighty patients received ICG and Tc99 with unilateral and bilateral SLN detection rates of 97.5% and 81.3%, respectively. Seventy-seven patients received all three tracers with unilateral and bilateral detection rates of 93.5% and 80.5%, respectively. Only one patient in the triple tracer group was detected by blue dye alone. No significant differences were noticed in unilateral or bilateral detection rates between the two groups, nor in the detection of lymph node metastasis.

CONCLUSION

The addition of blue dye to ICG and Tc99 did not demonstrate any improvement in SLN detection.

Sentinel lymph node mapping by near-infrared fluorescence imaging and contrast-enhanced ultrasound in healthy dogs

Sentinel lymph node (SLN) mapping is a valuable and crucial diagnostic procedure in staging malignancies. We compared two non-invasive techniques, near-infrared (NIR) fluorescence imaging and contrast-enhanced ultrasound (CEUS), to identify the SLNs in three superficial anatomical regions in an animal model. Six healthy laboratory dogs were included in a proof-of-concept trial. A NIR fluorescent dye (Indocyanine Green) and microbubbles (Sonovue) were consecutively injected subdermally in the Inguinal, axillary and popliteal region to map the SLNs. Transcutaneous NIR fluorescence imaging identified SLNs in 17 out of a total of 18 occasions. CEUS identified SLNs in all regions (18/18). Whereas NIR fluorescence imaging performed better in the visualization of the afferent lymphatic tract, CEUS demonstrated different filling patterns of the SLNs, a feature potentially critical for the concept of SLN mapping in cancer patients. Both NIR fluorescence imaging and CEUS are safe, non-invasive, practical and accurate methods to perform real-time transcutaneous SLN mapping with potential in a clinical setting.

Non-invasive sentinel lymph node mapping and needle guidance using clinical handheld photoacoustic imaging system in small animal

Translating photoacoustic imaging (PAI) into clinical setup is a challenge. Handheld clinical real-time PAI systems are not common. In this work, we report an integrated photoacoustic (PA) and clinical ultrasound imaging system by combining light delivery with the ultrasound probe for sentinel lymph node imaging and needle guidance in small animal. The open access clinical ultrasound platform allows seamless integration of PAI resulting in the development of handheld real-time PAI probe. Both methylene blue and indocyanine green were used for mapping the sentinel lymph node using 675 and 690 nm wavelength illuminations, respectively. Additionally, needle guidance with combined ultrasound and PAI was demonstrated using this imaging system. Up to 1.5 cm imaging depth was observed with a 10 Hz laser at an imaging frame rate of 5 frames per second, which is sufficient for future translation into human sentinel lymph node imaging and needle guidance for fine needle aspiration biopsy.

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.

Sentinel lymph node mapping in endometrial cancer: a systematic review and meta-analysis

Endometrial cancer is the most frequent tumor in the female reproductive system, while the sentinel lymph node (SLN) mapping for diagnostic efficacy of endometrial cancer is still controversial. This meta-analysis was conducted to evaluate the diagnostic value of SLN in the assessment of lymph nodal involvement in endometrial cancer. Forty-four studies including 2,236 cases were identified. The pooled overall detection rate was 83% (95% CI: 80-86%). The pooled sensitivity was 91% (95% CI: 87-95%). The bilateral pelvic node detection rate was 56% (95% CI: 48-64%). Use of indocyanine green (ICG) increased the overall detection rate to 93% (95% CI: 89-96%) and robotic-assisted surgery also increased the overall detection rate to 86% (95% CI: 79-93%). In summary, our meta-analysis provides strong evidence that sentinel node mapping is an accurate and feasible method that performs well diagnostically for the assessment of lymph nodal involvement in endometrial cancer. Cervical injection, robot-assisted surgery, as well as using ICG, optimized the sensitivity and detection rate of the technique. Sentinel lymph mapping may potentially leading to a greater utilization by gynecologic surgeons in the future.

Ex vivo sentinel lymph node mapping in colorectal cancer using a magnetic nanoparticle tracer to improve staging accuracy: a pilot study

AIM

Nodal status is the most important prognostic factor in colorectal cancer (CRC). Small occult metastases may remain undetected on conventional histopathological examination, potentially resulting in undertreatment. Ex vivo sentinel lymph node mapping (SLNM) can be used to improve the accuracy of nodal staging, but the currently used tracers suffer from drawbacks, which hamper implementation of the technique in routine clinical practice. Magnetic tracers are the optimal size for sentinel lymph node (SLN) retention and allow objective quantitative selection of SLNs; they therefore have great potential for SLNM in CRC. The study evaluates the feasibility of ex vivo magnetic SLNM and compares the performance of this technique with blue dye SLNM.

METHOD

Twenty-eight ex vivo SLNM procedures were performed in 27 histological node-negative patients with CRC using a magnetic tracer and blue dye. A magnetometer was used to select magnetic SLNs after formalin fixation of the CRC specimen. Both magnetic and blue SLNs were subjected to serial sectioning and immunohistochemical staining to reveal occult metastases.

RESULTS

At least one SLN was successfully identified in 27/28 (96%) and 25/28 (89%) of the cases with the magnetic technique and blue dye. Isolated tumour cells were detected in 10 patients. This was predicted with 100% sensitivity and accuracy using the magnetic technique, and with 91% sensitivity and 96% accuracy using the blue dye technique.

CONCLUSION

This study demonstrates that ex vivo magnetic SLNM is a feasible technique for use in routine clinical practice, improving nodal staging accuracy of CRC patients.

Sentinel Lymph Node Mapping in Patients with Endometrial Carcinoma: Less Can Be More

PURPOSE OF REVIEW

The role and extent of lymphadenectomy for endometrial carcinoma has been debated for over 30 years. Many clinicians argue that there is therapeutic value for lymphadenectomy in patients deemed to be "at risk", a designation not universally defined, despite the lack of randomized data supporting this argument. However, lymphadenectomy is associated with morbidity, including lower extremity lymphedema. Sentinel lymph node (SLN) mapping is emerging as a viable alternative to comprehensive lymphadenectomy in the surgical staging of patients with endometrial cancer.

RECENT FINDINGS

Nodal disease status is an important prognostic and predictive factor. Surgical staging with lymphadenectomy remains an important part of the treatment of patients with newly diagnosed endometrial carcinoma despite the dispute regarding its therapeutic value. Many clinicians have argued for abandoning lymphadenectomy altogether; however, this too is not ideal, as it may lead to under-treatment due to inadequate staging or over-treatment with toxic therapies.

SUMMARY

SLN mapping has emerged as a viable compromise between a comprehensive lymphadenectomy and no lymph node sampling in the surgical staging of these patients, and may lead to reduced morbidity risks. In this review, we present the currently available data in this area of research, as well as our experience with SLN mapping.

Lymph nodes and the melanoma surgeon: re-defining a long-term relationship

Surgeons now have an enhanced ability to stage patients with clinically localized cutaneous melanoma using sentinel lymph node biopsy. Despite this, the weight of clinical evidence is tilting in favor of a measured approach to pre-emptive lymph node removal. Careful consideration of whether traditional surgical approaches to the regional nodes, whether done in the name of 'staging' or pre-emptive removal of a potential site of relapse, really 'benefit' the patient is paramount for optimal care.

Cutaneous necrosis as a result of isosulphane blue injection in mammarian sentinel lymph node mapping: report of two cases

Skin-sparing mastectomy with sentinel lymph node biopsy (SLNB) and synchronous breast reconstruction are widely used in breast cancer surgery nowadays. Difficulties in feeling confident in this technique and postoperative surgical complications are the major obstacles against the widespread usage of this technique. Compared with the other surgical techniques, the complications are hard to treat. Cutaneous necrosis because of methylene blue used for sentinel lymph node mapping in patients who underwent skin-sparing mastectomy and SLNB is already reported in the literature. We present here two cases with cutaneous necrosis because of isosulphane blue injection after skin-sparing mastectomy and SLNB as a rare complication of dye injection.

Preclinical evaluation of robotic-assisted sentinel lymph node fluorescence imaging

An ideal substance to provide convenient and accurate targeting for sentinel lymph node (SLN) mapping during robotic-assisted surgery has yet to be found. We used an animal model to determine the ability of the FireFly camera system to detect fluorescent SLNs after administration of a dual-labeled molecular imaging agent.

METHODS

We injected the footpads of New Zealand White rabbits with 1.7 or 8.4 nmol of tilmanocept labeled with (99m)Tc and a near-infrared fluorophore, IRDye800CW. One and 36 h after injection, popliteal lymph nodes, representing the SLNs, were dissected with the assistance of the FireFly camera system, a fluorescence-capable endoscopic imaging system. After excision of the paraaortic lymph nodes, which represented non-SLNs, we assayed all lymph nodes for radioactivity and fluorescence intensity.

RESULTS

Fluorescence within all popliteal lymph nodes was easily detected by the FireFly camera system. Fluorescence within the lymph channel could be imaged during the 1-h studies. When compared with the paraaortic lymph nodes, the popliteal lymph nodes retain greater than 95% of the radioactivity at both 1 and 36 h after injection. At both doses (1.7 and 8.4 nmol), the popliteal nodes had higher (P < 0.050) optical fluorescence intensity than the paraaortic nodes at the 1- and 36-h time points.

CONCLUSION

The FireFly camera system can easily detect tilmanocept labeled with a near-infrared fluorophore at least 36 h after administration. This ability will permit image acquisition and subsequent verification of fluorescence-labeled SLNs during robotic-assisted surgery.

Simultaneous mapping of pan and sentinel lymph nodes for real-time image-guided surgery

The resection of regional lymph nodes in the basin of a primary tumor is of paramount importance in surgical oncology. Although sentinel lymph node mapping is now the standard of care in breast cancer and melanoma, over 20% of patients require a completion lymphadenectomy. Yet, there is currently no technology available that can image all lymph nodes in the body in real time, or assess both the sentinel node and all nodes simultaneously. In this study, we report an optical fluorescence technology that is capable of simultaneous mapping of pan lymph nodes (PLNs) and sentinel lymph nodes (SLNs) in the same subject. We developed near-infrared fluorophores, which have fluorescence emission maxima either at 700 nm or at 800 nm. One was injected intravenously for identification of all regional lymph nodes in a basin, and the other was injected locally for identification of the SLN. Using the dual-channel FLARE intraoperative imaging system, we could identify and resect all PLNs and SLNs simultaneously. The technology we describe enables simultaneous, real-time visualization of both PLNs and SLNs in the same subject.

Near infrared fluorescent chlorophyll nanoscale liposomes for sentinel lymph node mapping

BACKGROUND

Sentinel lymph node (SLN) mapping using in vivo near infrared fluorescence imaging has attracted great attention during the past few years. Here we report on the early use of poorly water-soluble chlorophyll with near infrared fluorescence extracted from the leaf of Chimonanthus salicifolius, for mouse axillary SLN mapping.

METHODS AND RESULTS

To improve the water solubility and SLN targeting of the chlorophyll, we encapsulated the chlorophyll in nanoscale liposomes. The liposome-coated chlorophyll nanocomposites obtained were spherical in shape and had an average diameter of 21.7 ± 6.0 nm. The nanocomposites dispersed well in water, and in aqueous suspension they exhibited brighter near infrared fluorescence than chlorophyll alone. After incubation of the nanocomposites with normal liver cells (QSG-7701) and macrophage cells (Ana-1) for no more than 48 hours, there was no obvious reduction in cell viability. When the nanocomposites were injected intradermally into the paw of a mouse, the axillary SLN was found to be strongly fluorescent and was easily visualized in real time without a requirement for surgery. The intensity of the near infrared fluorescence emitted by the SLN was obviously brighter than that emitted by the SLN of another mouse that had been intradermally injected with chlorophyll alone.

CONCLUSION

Our data show that the liposome-coated chlorophyll nanocomposites could have great potential for clinical SLN mapping due to their lack of toxicity, bright near infrared fluorescence, and small diameter.

Sentinel lymph node mapping for grade 1 endometrial cancer: is it the answer to the surgical staging dilemma?

OBJECTIVE

To describe the accuracy of SLN mapping in patients with a preoperative diagnosis of grade 1 endometrial cancer.

METHODS

A prospective, non-randomized study of women with a preoperative diagnosis of endometrial cancer and clinical stage I disease was conducted. A subset analysis of patients with a preoperative diagnosis of grade 1 endometrial endometrioid cancer was performed. All patients had preoperative lymphoscintigraphy with Tc99m on the day of or day before surgery followed by an intraoperative injection of 2 cm(3) of isosulfan or methylene blue dye deep into the cervix or both cervix and fundus. All patients underwent hysterectomy, bilateral salpingo-oophorectomy, and regional nodal dissection. Hot and/or blue nodes were labeled as SLNs and sent for histopathological analysis.

RESULTS

Forty-two patients with a preoperative diagnosis of grade 1 endometrial carcinoma treated from 3/06 to 8/08 were identified. Twenty-five (60%) had laparoscopic surgery; 17 (40%) were treated by laparotomy. Preoperative lymphoscintigraphy visualized SLNs in 30 patients (71%); intraoperative localization of the SLN was possible in 36 patients (86%). A median of 3 SLNs (range, 1-14) and 14.5 non-SLNs (range, 4-55) were examined. In all, 4/36 (11%) had positive SLNs-3 seen on H&E and 1 as cytokeratin-positive cells on IHC. All node-positive cases were picked up by the SLN; there were no false-negative cases. The sensitivity of the SLN procedure in the 36 patients who had an SLN identified was 100%.

CONCLUSION

Sentinel lymph node mapping using a cervical injection with combined Tc and blue dye is feasible and accurate in patients with grade 1 endometrial cancer and may be a reasonable option for this select group of patients. Regional lymphadenectomy remains the gold standard in many practices, particularly for the approximately 15% of cases with failed SLN mapping.