Combined use of ICG and technetium does not improve sentinel lymph node detection in endometrial cancer: Results of the COMBITEC study

Role of sentinel lymph node biopsy with indocyanine green and site of injection in endometrial cancer

PURPOSE OF REVIEW

The aim of the present narrative review is to summarize the state of art on sentinel lymph node biopsy (SLNB) in endometrial cancer, with a special focus on indocyanine green (ICG) as adopted tracer.

RECENT FINDINGS

Over the years, the surgical nodal staging in patients with endometrial cancer has been intensively investigated. Traditionally, systematic pelvic and para-aortic lymphadenectomy represented the gold standard surgical treatment to assess nodal involvement of the tumor. Through the last two decades, SLNB has gradually replaced lymphadenectomy as a more targeted procedure. A great heterogeneity of tracers and injection techniques have been proposed to perform SLNB. However, no universally accepted recommendations are still available.

SUMMARY

SLNB has nowadays almost replaced pelvic lymphadenectomy in low-risk endometrial cancers, offering a better safety profile while being related to a comparable nodal involvement sensitivity. Currently, ICG is considered to be the most used tracer among others. Different injection sites have been proposed, with different detection features. While ICG cervical injection is nowadays the suggested technique for SLNB, noncervical injection techniques, such as hysteroscopic and combined procedures, seem to have a better accuracy in para-aortic nodal assessment, which have a role in high-risk endometrial cancers.

RAISN: Robot-assisted Indocyanine Green-guided Sentinel Node Biopsy in Clinical Stage I Germ Cell Tumor

Robot-assisted imaging-guided sentinel lymph node biopsy is a novel technique that has not been widely investigated in testicular germ cell tumor (GCT). Current staging strategies have poor accuracy for prediction of occult metastatic disease in clinical stage I GCT. Feasibility studies have used 99mTc-nanocolloid staining during laparoscopic procedures. The RAISN trial is investigating robot-assisted lymph node resection guided by indocyanine green fluorescence imaging. This new diagnostic approach is potentially more precise and easier to apply, and is widely available. Confirmation of its utility could change the management of newly diagnosed GCT by reducing overtreatment and treatment-related toxicity.

Detecting Atypical Sentinel Lymph Nodes in Early-Stage Cervical Cancer Using a Standardized Technique with a Hybrid Tracer

BACKGROUND

Since October 2018, lymph node status has become part of the FIGO staging, given that it is one of the most important prognostic factors among women with CC. The aim was to determine the rate of atypical lymphatic drainage in patients with clinical early-stage cervical cancer using a hybrid tracer (ICG-99mTc nanocolloid).

METHODOLOGY

A prospective, observational, single-centre study conducted at Son Espases University Hospital between January 2019 and October 2023. Patients with clinical early-stage CC who underwent SLN mapping were included. External iliac and obturator nodes were defined as common locations. Para-aortic, common iliac, presacral, internal iliac, and parametrial nodes were defined as atypical locations.

RESULTS

Thirty-nine cases of CC were included. The overall SLN detection rate was 97.4%, with 89.5% bilaterally. Positive nodes were found in 21.1% of patients. Atypical lymphatic drainage was present in 8 out of 38 (21.1%) patients. Of all the SLNs biopsied (146), 10.3% corresponded to an atypical zone. SLN in the atypical area had a higher proportion of metastasis than the usual area (37.5% vs. 16.7%; p = 0.327).

CONCLUSIONS

SLN biopsy can detect unusual drainage in a significant proportion of patients. Atypical lymph nodes have a higher percentage of metastasis, which consequently improves staging and tailoring therapy. SLN mapping performed via a standardized surgical technique using a hybrid tracer (ICG-99mTc) could help in the identification of the "true SLN".

Application value of indocyanine green fluorescence imaging in guiding sentinel lymph node biopsy diagnosis of gastric cancer: Meta-analysis

BACKGROUND

Gastric cancer is a common malignant tumor of the digestive system worldwide, and its early diagnosis is crucial to improve the survival rate of patients. Indocyanine green fluorescence imaging (ICG-FI), as a new imaging technology, has shown potential application prospects in oncology surgery. The meta-analysis to study the application value of ICG-FI in the diagnosis of gastric cancer sentinel lymph node biopsy is helpful to comprehensively evaluate the clinical effect of this technology and provide more reliable guidance for clinical practice.

AIM

To assess the diagnostic efficacy of optical imaging in conjunction with indocyanine green (ICG)-guided sentinel lymph node (SLN) biopsy for gastric cancer.

METHODS

Electronic databases such as PubMed, Embase, Medline, Web of Science, and the Cochrane Library were searched for prospective diagnostic tests of optical imaging combined with ICG-guided SLN biopsy. Stata 12.0 software was used for analysis by combining the "bivariable mixed effect model" with the "midas" command. The true positive value, false positive value, false negative value, true negative value, and other information from the included literature were extracted. A literature quality assessment map was drawn to describe the overall quality of the included literature. A forest plot was used for heterogeneity analysis, and P < 0.01 was considered to indicate statistical significance. A funnel plot was used to assess publication bias, and P < 0.1 was considered to indicate statistical significance. The summary receiver operating characteristic (SROC) curve was used to calculate the area under the curve (AUC) to determine the diagnostic accuracy. If there was interstudy heterogeneity (I 2 > 50%), meta-regression analysis and subgroup analysis were performed.

RESULTS

Optical imaging involves two methods: Near-infrared (NIR) imaging and fluorescence imaging. A combination of optical imaging and ICG-guided SLN biopsy was useful for diagnosis. The positive likelihood ratio was 30.39 (95%CI: 0.92-1.00), the sensitivity was 0.95 (95%CI: 0.82-0.99), and the specificity was 1.00 (95%CI: 0.92-1.00). The negative likelihood ratio was 0.05 (95%CI: 0.01-0.20), the diagnostic odds ratio was 225.54 (95%CI: 88.81-572.77), and the SROC AUC was 1.00 (95%CI: The crucial values were sensitivity = 0.95 (95%CI: 0.82-0.99) and specificity = 1.00 (95%CI: 0.92-1.00). The Deeks method revealed that the "diagnostic odds ratio" funnel plot of SLN biopsy for gastric cancer was significantly asymmetrical (P = 0.01), suggesting significant publication bias. Further meta-subgroup analysis revealed that, compared with fluorescence imaging, NIR imaging had greater sensitivity (0.98 vs 0.73). Compared with optical imaging immediately after ICG injection, optical imaging after 20 minutes obtained greater sensitivity (0.98 vs 0.70). Compared with that of patients with an average SLN detection number < 4, the sensitivity of patients with a SLN detection number ≥ 4 was greater (0.96 vs 0.68). Compared with hematoxylin-eosin (HE) staining, immunohistochemical (+ HE) staining showed greater sensitivity (0.99 vs 0.84). Compared with subserous injection of ICG, submucosal injection achieved greater sensitivity (0.98 vs 0.40). Compared with 5 g/L ICG, 0.5 and 0.05 g/L ICG had greater sensitivity (0.98 vs 0.83), and cT1 stage had greater sensitivity (0.96 vs 0.72) than cT2 to cT3 clinical stage. Compared with that of patients ≤ 26, the sensitivity of patients > 26 was greater (0.96 vs 0.65). Compared with the literature published before 2010, the sensitivity of the literature published after 2010 was greater (0.97 vs 0.81), and the differences were statistically significant (all P < 0.05).

CONCLUSION

For the diagnosis of stomach cancer, optical imaging in conjunction with ICG-guided SLN biopsy is a therapeutically viable approach, especially for early gastric cancer. The concentration of ICG used in the SLN biopsy of gastric cancer may be too high. Moreover, NIR imaging is better than fluorescence imaging and may obtain higher sensitivity.

Sentinel lymph node biopsy in endometrial cancer: When, how and in which patients

The role of nodal dissection in patients with endometrial cancer has been intensively studied in several studies. Historically, systematic pelvic and para-aortic lymphadenectomy represented the gold standard surgical treatment to assess potential nodal involvement and consequently define the appropriate stage of the tumor. Over the last years, sentinel node biopsy (SLNB) has been introduced as a more targeted alternative to lymph node dissection for lymph node staging and it has become popular among gynecologic oncologists. However, no level A evidence is still available, and several features of the SLNB technique have been matter of discussion among clinicians and a universally accepted methodology is still not currently available. This narrative review aims to summarize the body of knowledge on SLNB to offer the reader a complete picture about the evolution of this technique over the last decades.

Clinical outcomes of sentinel node navigation surgery in patients with preoperatively estimated stage IA endometrial cancer and evaluation of validity for continuing sentinel node navigation surgery based on dispersion of recurrence probability

BACKGROUND

To evaluate the feasibility of the use and continuation of sentinel lymph node navigation surgery (SNNS) as an alternative to pelvic lymph node dissection (PLND) for patients with preoperatively estimated stage IA endometrial cancer.

METHODS

This retrospective study selected the electronic medical records of all patients who had received CT scans and MRI imaging before surgery from April 1, 2009 to March 31, 2021. Sentinel lymph nodes (SLNs) were detected by administrating 99mTc-phytate and/or indocyanine green into the cervix, and the clinical outcomes of the patients who underwent SNNS or PLND were evaluated. Furthermore, in case of nodal recurrence, a new procedure to determine whether the facility should continue with SNNS or not was developed that compares the maximum likelihood hypothesis and an alternative one based on recurrence rates.

RESULTS

Among 137 patients, SLN biopsies with ultrastaging were performed on 91 patients. The SLN detection rate was 95.6%. Over a 59-month median observation period, no statistically significant differences were shown in overall survival, disease-specific survival and disease-free survival between the SNNS and PLND groups when introducing the propensity score method (p-values: 0.06, 0.153, and 0.625, respectively). Our procedure demonstrated that, in our department without recurrence up to the 65th attempt, it was possible to continue SNNS if a recurrence occurs at the 66th attempt.

CONCLUSION

This study suggests the validity of SNNS as an alternative to PLND. Even in the absence of evidence from randomized controlled trials, we can confirm the validity of continuing SNNS using our procedure.

Indocyanine green near-infrared imaging-guided lymph node dissection during oesophageal cancer surgery: A single-centre experience

Objective

This study aimed to investigate the feasibility of using indocyanine green (ICG) near-infrared (NIR) imaging during lymphadenectomy for oesophageal cancer.

Methods

Eighty-seven patients with primary oesophageal cancer were enrolled in this study. All the enrolled patients received an endoscopic injection of ICG between 40 min and 23 h before surgery. Nodal dissection during surgery was performed under fluorescence imaging visualisation, with the NIR signal shown in purple. ICG⁺ or ICG^- nodes were recorded station by station and were microscopically evaluated.

Results

Endoscopic peritumoral ICG injection was successfully performed in all patients. Major post-surgery complications included wound infection, pleural effusion, dysphonia, pneumonia and anastomotic fistula. No patients experienced ICG-related adverse events. A total of 2,584 lymph nodes were removed, and the mean number of lymph nodes for each patient was 29.70 ± 9.24. Most of the removed nodes (97.83%) were ICG⁺, and 3.32% of the ICG⁺ nodes were metastatic. No metastatic nodes were ICG^- or belonged to an ICG^- lymph node station. The time from ICG injection to surgery did not affect the number of harvested lymph nodes.

Conclusions

The use of ICG-NIR imaging during oesophageal cancer surgery can enhance the visualisation of lymph nodes during surgery. It is a feasible, safe and helpful technique for lymphadenectomy.

Robotically assisted augmented reality system for identification of targeted lymph nodes in laparoscopic gynecological surgery: a first step toward the identification of sentinel node : Augmented reality in gynecological surgery

BACKGROUND

To prove feasibility of multimodal and temporal fusion of laparoscopic images with preoperative computed tomography scans for a real-time in vivo-targeted lymph node (TLN) detection during minimally invasive pelvic lymphadenectomy and to validate and enable such guidance for safe and accurate sentinel lymph node dissection, including anatomical landmarks in an experimental model.

METHODS

A measurement campaign determined the most accurate tracking system (UR5-Cobot versus NDI Polaris). The subsequent interventions on two pigs consisted of an identification of artificial TLN and anatomical landmarks without and with augmented reality (AR) assistance. The AR overlay on target structures was quantitatively evaluated. The clinical relevance of our system was assessed via a questionnaire completed by experienced and trainee surgeons.

RESULTS

An AR-based robotic assistance system that performed real-time multimodal and temporal fusion of laparoscopic images with preoperative medical images was developed and tested. It enabled the detection of TLN and their surrounding anatomical structures during pelvic lymphadenectomy. Accuracy of the CT overlay was > 90%, with overflow rates < 6%. When comparing AR to direct vision, we found that scores were significatively higher in AR for all target structures. AR aided both experienced surgeons and trainees, whether it was for TLN, ureter, or vessel identification.

CONCLUSION

This computer-assisted system was reliable, safe, and accurate, and the present achievements represent a first step toward a clinical study.

The Role of Sentinel Lymph Node Mapping in High-grade Endometrial Cancer

OPINION STATEMENT

Total hysterectomy with lymph node assessment is the current standard-of-care for surgical staging in apparent early-stage endometrial cancer. Compared to the traditional complete pelvic lymphadenectomy with or without para-aortic lymphadenectomy, sentinel lymph node (SLN) mapping results in fewer surgical complications, decreased operative time, and lower rates of chronic lymphedema. The technique is endorsed by the National Comprehensive Cancer Network and the Society of Gynecologic Oncology guidelines, and over the past two decades the majority of gynecologic oncologists worldwide have adopted SLN mapping into their practice. However, as the results of the initial SLN studies were mostly based on low-grade tumors, adoption of the technique in high-grade tumors has been slower and more controversial. In this review, we discuss the most recent studies evaluating the SLN mapping in high-grade endometrial cancers. The results of these studies suggest that the SLN detection rate is acceptably high and the negative predictive value is sufficiently low to support the use of SLN mapping in high-grade endometrial tumors to replace complete lymphadenectomy. Validity of SLN mapping techniques does, however, require following a standard algorithm, and success depends also on surgeon expertise. Moreover, the impact of SLN mapping on overall survival in high-grade tumors requires future prospective randomized studies. Finally, a transition toward near-universal SLN mapping techniques for endometrial cancers could significantly impact on the adequacy of gynecologic oncology fellows' surgical training and competency in lymphadenectomy.

Sentinel Lymph Node Mapping in High-Grade Endometrial Cancer

Sentinel lymph node (SLN) mapping is becoming an acceptable alternative to full lymphadenectomy for evaluating lymphatic spread in clinical stage I endometrial cancer (EC). While the assessment of pelvic and para-aortic lymph nodes is part of the surgical staging of EC, there is a long-standing debate over the therapeutic value of full lymphadenectomy in this setting. Although lymphadenectomy offers critical information on lymphatic spread and prognosis, most patients will not derive oncologic benefit from this procedure as the majority of patients do not have lymph node involvement. SLN mapping offers prognostic information while simultaneously avoiding the morbidity associated with an extensive and often unnecessary lymphadenectomy. A key factor in the decision making when planning for EC surgery is the histologic subtype. Since the risk of lymphatic spread is less than 5% in low-grade EC, these patients might not benefit from lymph node assessment. Nonetheless, in high-grade EC, the risk for lymph node metastases is much higher (20–30%); therefore, it is crucial to determine the spread of disease both for determining prognosis and for tailoring the appropriate adjuvant treatment. Studies on the accuracy of SLN mapping in high-grade EC have shown a detection rate of over 90%. The available evidence supports adopting the SLN approach as an accurate method for surgical staging. However, there is a paucity of prospective data on the long-term oncologic outcome for patients undergoing SLN mapping in high-grade EC, and more trials are warranted to answer this question.

Sentinel Lymph Node Biopsy in Endometrial Cancer: Dual Injection, Dual Tracer—A Multidisciplinary Exhaustive Approach to Nodal Staging

Simple Summary

Since clinical guidelines accepted the utilization of sentinel lymph node (SLN) in apparent uterine-confined endometrial cancer (EC), many centers have already used it as a standard staging surgery. The most widely accepted tracer is ICG alone, but several studies comment on the importance of surgeon experience in order not to lose sensitivity in the first 30-40 cases. This is a prospective, observational single-center trial designed to improve SLN detection rate specially during learning curve. The application of dual tracer (indocyanine green (ICG) and Technetium99 (Tc99) injected separately) helps us to reach a very good overall and bilateral SLN pelvic detection rate in early-stage endometrial cancer patients. Dual injection (cervical and fundal) improves para-aortic SLN detection rate.

Abstract

Introduction: Sentinel lymph node (SLN) has recently been introduced as a standard staging technique in endometrial cancer (EC). There are some issues regarding team experience and para-aortic detection. Objective: to report the accuracy of SLN detection in EC with a dual tracer (ICG and Tc99) and dual injection site (cervix and fundus) during the learning curve. Methods: A prospective, observational single-center trial including 48 patients diagnosed with early-stage EC. Dual intracervical tracer (Tc99 and ICG) was injected at different times. High-risk patients had a second fundus injection with both tracers. Results: the detection rates were as follows: 100% (48/48) overall for SLNs; 98% (47/48) overall for pelvic SLNs; 89.5% (43/48) for bilateral SLNs; and 2% (1/48) for isolated para-aortic SLNs. In high-risk patients, the para-aortic overall DR was 66.7% (22/33); 60.7% (17/28) with ICG and 51.5% (17/33) with Tc99 (p = 0.048)). Overall rate of lymph node involvement was 14.6% (7/48). Macroscopic pelvic metastasis was found in four patients (8.3%) and microscopic in one case (2%). No metastasis was found in any para-aortic SLNs. Half of the patients with positive pelvic SLNs had positive para-aortic nodes. In high-risk patients, when para-aortic SLNs mapped failed, 36.4% (4/11) had positive nodes in para-aortic lymphadenectomy. The sensitivity and negative predictive value (NPV) of SLN pelvic detection was 100%. Conclusions: Multidisciplinary exhaustive approach gives a suitable accuracy of SLN during learning curve. Dual injection (cervical and fundal) with dual tracer (ICG and Tc99) offers good overall detection rates and increases para-aortic SLN detection.

Utility of indocyanine green as a single tracer for sentinel node biopsy in endometrial cancer

AIM

Our study aims to investigate the safety and effectiveness of sentinel lymph node biopsy using indocyanine green (ICG) for the surgical staging of early-stage endometrial cancer in comparison to technetium-99 m use.

METHODS

We conducted an observational retrospective study with patients diagnosed of endometrial cancer and FIGO stages I-II. All participants were injected technetium-99m the day prior to the surgery and underwent lymphoscintigraphy along with single-photon emission computed tomography. In addition, all patients were administered intraoperatively ICG injection to detect sentinel lymph node biopsy. The surgical staging was then completed according to the European Society for Medical Oncology preoperative risk category. Data obtained from the analysis of technetium-99m detection was compared to ICG detection.

RESULTS

A total of 53 women with endometrial cancer were included in the study, 49 (92.5%) of them showed drainage preoperatively in the single-photon emission computed tomography and/or lymphoscintigraphy. The intraoperative bilateral detection rate for technetium-99 m was 26 (49.1%) patients compared to 40 (75.5%) patients with ICG (p = 0.013). We observed a 42.5% increase in the mean number of lymph nodes retrieved by ICG compared to technetium-99m (2.85 vs 2,0 nodes; p = 0.002). We intraoperatively identified 164 lymph nodes, 104 (63.4%) located in both obturator areas and external iliac vessels.

CONCLUSION

The use of ICG for the performance of sentinel node biopsy in patients with endometrial cancer seems safe and could be superior to technetium-99 m, since it offers a higher bilateral detection rate and nodal retrieval, resulting in the possibility to perform safely less full staging lymphadenectomies.