Avoiding Full Lymphadenectomies in Intermediate- and High-Risk Endometrial Cancer by Sentinel Lymph Node Biopsy Implementation

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.

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.

Risk factors associated with false negative rate of sentinel lymph node biopsy in endometrial cancer: a systematic review and meta-analysis

Objective

Currently, sentinel lymph node biopsy (SLNB) is increasingly used in endometrial cancer, but the rate of missed metastatic lymph nodes compared to systemic lymph node dissection has been a concern. We conducted a systematic review and meta-analysis to evaluate the false negative rate (FNR) of SLNB in patients with endometrial cancer and to explore the risk factors associated with this FNR.

Data sources

Three databases (PubMed, Embase, Web of Science) were searched from initial database build to January 2023 by two independent reviewers.

Research eligibility criteria

Studies were included if they included 10 or more women diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage I or higher endometrial cancer, the study technique used sentinel lymph node localization biopsy, and the reported outcome metrics included false negative and/or FNR.

Study appraisal and synthesis methods

Two authors independently reviewed the abstracts and full articles. The FNR and factors associated with FNR were synthesized through random-effects meta-analyses and meta-regression.

The results

We identified 62 eligible studies. The overall FNR for the 62 articles was 4% (95% CL 3-5).There was no significant difference in the FNR in patients with high-risk endometrial cancer compared to patients with low-risk endometrial cancer. There was no difference in the FNR for whether frozen sections were used intraoperatively. The type of dye used intraoperatively (indocyanine green/blue dye) were not significantly associated with the false negative rate. Cervical injection reduced the FNR compared with alternative injection techniques. Indocyanine green reduced the FNR compared with alternative Tc-99m. Postoperative pathologic ultrastaging reduced the FNR.

Conclusions

Alternative injection techniques (other than the cervix), Tc-99m dye tracer, and the absence of postoperative pathologic ultrastaging are risk factors for a high FNR in endometrial cancer patients who undergo SLNB; therefore, we should be vigilant for missed diagnosis of metastatic lymph nodes after SLNB in such populations.

Systematic review registration

http://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023433637.

An Extraordinary Location of Sentinel Lymph Nodes in a Patient with Endometrial Cancer

OBJECTIVE

To show dissection of sentinel lymph nodes.

DESIGN

A step-by-step demonstration of the technique with narration.

SETTING

Endometrial cancer (EC) is the most common gynecologic malignancy worldwide. Sentinel lymph node biopsy with indocyanine green (ICG) has become more widely used and has been featured in recently published guidelines for EC [1]. Minimally invasive approaches with the sentinel lymph node concept (conventional laparoscopy, laparoscopic-assisted vaginal surgeries or robotic) to EC staging have resulted in lower rates of peri- and postoperative complications than conventional staging procedures [2].

INTERVENTIONS

No video article has been published in the literature about high pelvic, para-aortic sentinel lymph node dissection. An informed consent form was obtained from the patient. An institutional review board approval was not required. A 45-year-old female with gravidity 0, parity 0, and body mass index of 23.4 kg/m2 presented with complaints of abnormal uterine bleeding (spotting). Increased endometrial thickness was detected on transvaginal ultrasound (10 mm) in the postmenstrual period. Endometrioid-type endometrial adenocancer with focal squamous differentiation International Federation of Gynecology and Obstetrics grade I was detected on endometrial biopsy. The patient had hepatitis B virus positivity and no other chronic disease. A laparotomic myomectomy had been performed in 2016. Laparoscopic high pelvic, low para-aortic sentinel lymph node dissection with ICG and hysterectomy (without uterine manipulator) + bilateral salpingo-oophorectomy were performed (Supplemental Video 1). The operation time for the procedure was 110 minutes and the estimated blood loss was <20 mL. No major complications occurred during or after the surgery. The patient stayed in the hospital for 1 day. The final pathology result showed an International Federation of Gynecology and Obstetrics grade I, endometrioid-type endometrial adenocancer with focal squamous differentiation, as a 1.5 × 1 cm tumorous mass invading less than one-half of the myometrium. Neither lymphovascular invasion nor sentinel lymph node metastasis was detected. A multicenter, prospective study showed that sentinel lymph node dissection with ICG in clinical stage 1 EC is feasible and has a high degree of diagnostic accuracy in detecting EC metastases. In that study, isolated para-aortic sentinel lymph node was detected in 3 of 340 patients (<1%) [2]. Another study reported the detection rate of isolated para-aortic sentinel lymph node to be 1.1% in patients with intermediate- and high-risk EC [3].

CONCLUSION

There are in some cases 2 distinct channels emanating from one side, and it is important to follow each and to acknowledge there may be more than one sentinel, one of which is lower in a typical location and one higher as in this case. This video article is the first video demonstration of bilateral isolated high pelvic, para-aortic sentinel lymph node dissection in EC.

Comparison of oncological outcomes between sentinel lymph node biopsy and complete lymphadenectomy for endometrial cancer

AIM

Sentinel lymph node (SLN) mapping allows node-negative patients to be spared from the surgical comorbidities associated with total lymphadenectomy. This study aimed to evaluate the oncological outcomes of SLN biopsy versus complete lymph node dissection in patients with early-stage endometrial carcinoma.

METHODS

Retrospective analyses were performed in patients with pathologically confirmed endometrioid endometrial carcinoma, who underwent minimally invasive surgical staging with SLN biopsy or complete lymph node dissection at Yonsei Cancer Center between 2015 and 2019.

RESULTS

A total of 301 patients were included in this study. Eighty-two patients underwent SLN biopsy, while 219 underwent complete lymph node dissection. There were no significant differences in patient characteristics between the two groups. In terms of operative characteristics, the SLN biopsy-only group had a significantly shorter surgical duration (p < 0.001) than the lymphadenectomy group. The mean follow-up period was 41.4 months. There were no differences in progression-free survival (PFS) and overall survival (OS) between the two groups (SLN biopsy vs. complete lymph node dissection; p = 0.798 and 0.301, respectively). Multivariate analysis revealed that SLN biopsy was not an independent prognostic factor for PFS or OS.

CONCLUSION

Our results showed that SLN biopsy provided oncological outcomes similar to those of lymphadenectomy.

Personalized Sentinel Node Mapping in Endometrial Cancer by the Indocyanine Green Implementation as Single Tracer: A Case Control Study

The main objective was to analyze the rate of bilateral sentinel lymph node (SLN) detection in endometrial cancer using indocyanine green (ICG) as a unique tracer compared to Technetium99 + ICG. As secondary objectives, we analyzed the drainage pattern and factors that might affect the oncological outcomes. A case-control ambispective study was carried out on consecutive patients at our center. Data on the SLN biopsy with ICG collected prospectively were compared to retrospective data on the use of a double-tracer technique including Technetium99 + ICG. In total, 194 patients were enrolled and assigned to both groups, in which the group with both tracers (controls) included 107 (54.9%) patients and the ICG-alone group (cases) included 87 (45.1%) patients. The rate of bilateral drainage was significantly higher in the ICG group (98.9% vs. 89.7%; p = 0.013). The median number of nodes retrieved was higher in the control group (three vs. two nodes; p < 0.01). We did not find survival differences associated with the tracer used (p = 0.85). We showed significant differences in terms of disease-free survival regarding the SLN location (p < 0.01), and obturator fossa retrieved nodes showed better prognosis compared to external iliac. The use of ICG as a single tracer for SLN detection in endometrial cancer patients seemed to obtain higher rates of bilateral detection with similar oncological outcomes.

External validation study of endometrial cancer preoperative risk stratification model (ENDORISK)

Introduction

Among industrialized countries, endometrial cancer is a common malignancy with generally an excellent outcome. To personalize medicine, we ideally compile as much information as possible concerning patient prognosis prior to effecting an appropriate treatment decision. Endometrial cancer preoperative risk stratification (ENDORISK) is a machine learning–based computational Bayesian networks model that predicts lymph node metastasis and 5-year disease-specific survival potential with percentual probability. Our objective included validating ENDORISK effectiveness in our patient cohort, assessing its application in the current use of sentinel node biopsy, and verifying its accuracy in advanced stages.

Methods

The ENDORISK model was evaluated with a retrospective cohort of 425 patients from the University Hospital Brno, Czech Republic. Two hundred ninety-nine patients were involved in our disease-specific survival analysis; 226 cases with known lymph node status were available for lymph node metastasis analysis. Patients were included undergoing either pelvic lymph node dissection (N = 84) or sentinel node biopsy (N =70) to explore the accuracy of both staging procedures.

Results

The area under the curve was 0.84 (95% confidence interval [CI], 0.77–0.9) for lymph node metastasis analysis and 0.86 (95% CI, 0.79–0.93) for 5-year disease-specific survival evaluation, indicating quite positive concordance between prediction and reality. Calibration plots to visualize results demonstrated an outstanding predictive value for low-risk cancers (grades 1–2), whereas outcomes were underestimated among high-risk patients (grade 3), especially in disease-specific survival. This phenomenon was even more obvious when patients were subclassified according to FIGO clinical stages.

Conclusions

Our data confirmed ENDORISK model’s laudable predictive ability, particularly among patients with a low risk of lymph node metastasis and expected favorable survival. For high-risk and/or advanced stages, the ENDORISK network needs to be additionally trained/improved.

Usefulness and potential pitfalls of pre-operative PET-CT in patients with endometrial cancer undergoing one- and two-step sentinel lymph node mapping: Do negative findings on PET-CT negativity really indicate node negativity?

OBJECTIVE

We investigated the utility of Positron emission tomography-Computed tomography (PET-CT) in the setting of two different sentinel lymph node (SLN) mapping techniques; the conventional cervical injection method (one-step) and the two-step method, which involves fundal injection followed by cervical injection.

METHODS

Patients with endometrial cancer undergoing FDG PET-CT followed by laparoscopic or robotic surgical staging with SLN mapping at the Yonsei Cancer Center between July 2014 and April 2021 were stratified into the PET-positive group (with suspected or likely lymph nodes metastasis) and PET-negative group. A chart review was performed for the number of harvested SLNs, patterns of SLN metastases, and recurrence.

RESULTS

Among 466 patients undergoing one-step (n = 276) and two-step (n = 190) SLN mapping, LN metastasis was identified in 21 of 434 PET-negative and 18 of 32 PET-positive patients. The sensitivity and specificity of PET-CT for diagnosing lymph node metastasis were 46.2% and 96.7%, respectively. Among PET-positive patients with LN metastasis, anatomical distribution was concordant in 14/18 patients (77.8%). Among PET-negative patients, four (2.3%) had metastatic para-aortic SLNs, including three (1.7%) with isolated para-aortic metastases; metastatic para-aortic SLNs were exclusively found in the two-step group. Among PET-positive patients, para-aortic SLN metastasis was identified in 35.7% of two-step and 16.7% of one-step group. Among the 21 PET false-negative patients, recurrence was seen in four patients (19%) after a median follow-up of 34 months (range: 7-70 months).

CONCLUSIONS

PET-CT served as a useful guide to clinicians with high anatomical concordance rate in patients with LN metastasis. However, despite high specificity, sensitivity was limited. SLN metastasis pattern, especially at the para-aortic level, indicates that the two-step SLN technique might be useful in PET-negative and PET-positive patients.