Current state of sentinel lymph nodes for women with endometrial cancer

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.

Accuracy and Survival Outcomes after National Implementation of Sentinel Lymph Node Biopsy in Early Stage Endometrial Cancer

BACKGROUND

Sentinel lymph node (SLN) biopsy has recently been accepted to evaluate nodal status in endometrial cancer at early stage, which is key to tailoring adjuvant treatments. Our aim was to evaluate the national implementation of SLN biopsy in terms of accuracy to detect nodal disease in a clinical setting and oncologic outcomes according to the volume of nodal disease.

PATIENTS AND METHODS

A total of 29 Spanish centers participated in this retrospective, multicenter registry including patients with endometrial adenocarcinoma at preoperative early stage who had undergone SLN biopsy between 2015 and 2021. Each center collected data regarding demographic, clinical, histologic, therapeutic, and survival characteristics.

RESULTS

A total of 892 patients were enrolled. After the surgery, 12.9% were suprastaged to FIGO 2009 stages III-IV and 108 patients (12.1%) had nodal involvement: 54.6% macrometastasis, 22.2% micrometastases, and 23.1% isolated tumor cells (ITC). Sensitivity of SLN biopsy was 93.7% and false negative rate was 6.2%. After a median follow up of 1.81 years, overall surivial and disease-free survival were significantly lower in patients who had macrometastases when compared with patients with negative nodes, micrometastases or ITC.

CONCLUSIONS

In our nationwide cohort we obtained high sensitivity of SLN biopsy to detect nodal disease. The oncologic outcomes of patients with negative nodes and low-volume disease were similar after tailoring adjuvant treatments. In total, 22% of patients with macrometastasis and 50% of patients with micrometastasis were at low risk of nodal metastasis according to their preoperative risk factors, revealing the importance of SLN biopsy in the surgical management of patients with early stage EC.

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.

Lymphadenectomy for high-grade endometrial cancer: Does it impact lymph node recurrence?

INTRODUCTION

The diagnostic role of lymph node (LN) assessment is established in endometrial cancer. Our study assesses whether surgical removal of metastatic LNs has oncologic benefit in high-grade endometrial cancer.

MATERIALS AND METHODS

High-grade endometrial cancer cases (2000-2010) were collected from two tertiary cancer centres. In patients with at least one positive LN, recurrence free survival (RFS) was compared by the number of LNs removed. Factors predicting nodal recurrence (NR) were explored. Univariate statistical analyses by log rank test and multivariable cox proportional hazards model were performed using SAS version 9.4.

RESULTS

Of 570 patients identified, 334 patients underwent staging lymphadenectomy, 74 (22.2%) patients had at least one positive LN. The median RFS with at least one positive lymph node was 87.1 months (95% CI ≥ 14.3) when greater than 15 LNs were removed, compared to 16.9 months (95% CI, 13.6-35.6) and 17.3 months (95% CI, 8.5-39.8) when 5-15 and less than 5 LNs were removed, respectively (p = 0.02). In the cohort of 570 patients, there were 167 disease recurrences with location described on imaging, 98 (58.7%) had a NR and 69 (41.3%) recurred at other sites. Multivariable modeling identified that only positive LNs at surgical staging predicted NR (HR 3.8, 95% CI 1.4-10.2).

CONCLUSION

In high-grade endometrial cancer, positive LNs predict NR, and RFS is longer with a more extensive LN dissection in women with positive LNs. Future prospective studies should evaluate the oncologic benefit of surgical removal of metastatic LNs in high-grade endometrial cancer.

Status of Sentinel Lymph Node Biopsy in Endometrial Cancer

The role of lymphadenectomy in surgical staging remains one of the biggest controversies in the management of endometrial cancer. The concept of sentinel lymph node biopsy in endometrial cancer has been evaluated for a number of years, with promising sensitivity rates and negative predictive values. The possibility of adequate staging while avoiding systematic lymphadenectomy leads to a significant reduction in the rate of peri- and postoperative morbidity. Nevertheless, the status of sentinel lymph node biopsy in endometrial cancer has not yet been fully elucidated and is variously assessed internationally. According to current European guidelines and recommendations, sentinel lymph node biopsy in endometrial cancer should be performed only in the context of clinical studies. In this review article, the developments of the past decade are explored concisely. In addition, current data regarding the technical aspects, accuracy and prognostic relevance of sentinel lymph node biopsy are explained and evaluated critically.

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

OBJECTIVE

There is scarce evidence available about the benefit of combining technetium (^99mTc) and indocyanine green (ICG) for sentinel lymph node (SLN) biopsy in endometrial cancer. The aim of this study was to compare the overall and bilateral pelvic detection rates of SLNs in two retrospective cohorts: ICG exclusive vs. combined ICG+^99mTc.

METHODS

The COMBITEC study (COMBined ICG and Technetium for SLN detection in Endometrial Cancer) consisted of a multicentre retrospective study (February 2015-June 2020) including patients diagnosed with endometrial atypical hyperplasia or early-stage endometrial carcinoma who underwent SLN biopsy by cervical injection of ICG with or without ^99mTc in four different referral centers in Spain.

RESULTS

A total of 180 patients were included, 51% (n = 92) in ICG group and 49% (n = 88) in ICG+^99mTc group. Eighty-seven percent of the patients presented endometrioid histology, and over 99% of the procedures were performed by a minimally invasive approach. Both groups were comparable regarding their basal characteristics, except for a higher body mass index in ICG+^99mTc group and a bigger proportion of robotic-assisted procedures in ICG group. Overall detection rate was 92.8% without significant differences between groups (ICG: 94.6% vs ICG+^99mTc: 90.9%, p = .34). No significant differences were observed neither in bilateral pelvic nor aortic mapping rate. When ^99mTc was used, surgical procedures were significantly longer. In 7.3% of mapped patients, at least one positive SLN was found (ICG: 10.3% vs ICG+^99mTc: 3.9%, p = .109). Empty node packet rates and number of SLNs retrieved per patient were also similar between cohorts.

CONCLUSION

Combining preoperative ^99mTc to intraoperative ICG did not improve SLN detection in endometrial cancer, but resulted in longer procedures.

Report from the European Society of Gynaecological Oncology (ESGO) 2020 State-of-the-Art Virtual Meeting

This is a report from the European Society of Gynaecological Oncology State-of-the-Art Virtual Meeting held December 14-16, 2020. The unique 3-day conference offered comprehensive state-of-the-art summaries on the major advances in the treatment of different types of gynecological cancers. Sessions opened with a case presentation followed by a keynote lecture and interactive debates with opinion leaders in the field. The speakers also presented scientific reviews on the clinical trial landscape in collaboration with the European Network of Gynecological Oncological Trial (ENGOT) groups. In addition, the new ESGO-ESRTO-ESP endometrial cancer guidelines were officially presented in public. This paper describes the key information and latest studies that were presented for the first time at the conference.

Paucity of data evaluating patient centred outcomes following sentinel lymph node dissection in endometrial cancer: A systematic review

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SLND has potentially favourable patient-centred outcomes over systematic LND.

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High-quality evidence comparing SLND with other methods of staging is lacking.

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SLND was associated with shorter operating times and lower estimated blood loss.

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Intraoperative and postoperative complications were not conclusively different.

Sentinel lymph node dissection (SLND) is presently used by the majority of gynaecologic oncologists for surgical staging of endometrial cancer. SLND assimilated into routine surgical practice because it increases precision of surgical staging and may reduce morbidity compared to a full, systematic LND. Previous research focussed on the accuracy of SLND. Patient centred outcomes have never been conclusively demonstrated. The objective of this systematic review was to evaluate patient centred outcomes of SLND for endometrial cancer patients. Literature published in the last five years (January 2015 to April 2020) was retrieved from PubMed, EMBASE, and Cochrane library, across five domains: (1) perioperative outcomes; (2) adjuvant treatment; (3) patient-reported outcomes (PROs); (4) lymphedema, and (5) cost. Covidence software ascertained a standardised and monitored review process. We identified 21 eligible studies. Included studies were highly heterogeneous, with widely varying outcome measures and reporting. SLND was associated with shorter operating times and lower estimated blood loss compared to systematic LND, but intra-operative and post-operative complications were not conclusively different. There was either no impact, or a trend towards less adjuvant treatment used in patients with SLND compared to systematic LND. SLND had lower prevalence rates of lymphedema compared to systematic LND, although this was shown only in three retrospective studies. Costs of surgical staging were lowest for no node sampling, followed by SLND, then LND. PROs were unable to be compared because of a lack of studies. The quality of evidence on patient-centred outcomes associated with SLND for surgical staging of endometrial cancer is poor, particularly in PROs, lymphedema and cost. The available studies were vulnerable to bias and confounding.

Registration of Systematic Review: PROSPERO (CRD42020180339)

Development of a surgical competency assessment tool for sentinel lymph node dissection by minimally invasive surgery for endometrial cancer

INTRODUCTION

Sentinel lymph node dissection is widely used in the staging of endometrial cancer. Variation in surgical techniques potentially impacts diagnostic accuracy and oncologic outcomes, and poses barriers to the comparison of outcomes across institutions or clinical trial sites. Standardization of surgical technique and surgical quality assessment tools are critical to the conduct of clinical trials. By identifying mandatory and prohibited steps of sentinel lymph node (SLN) dissection in endometrial cancer, the purpose of this study was to develop and validate a competency assessment tool for use in surgical quality assurance.

METHODS

A Delphi methodology was applied, included 35 expert gynecological oncology surgeons from 16 countries. Interviews identified key steps and tasks which were rated mandatory, optional, or prohibited using questionnaires. Using the surgical steps for which consensus was achieved, a competency assessment tool was developed and subjected to assessments of validity and reliability.

RESULTS

Seventy percent consensus agreement standardized the specific mandatory, optional, and prohibited steps of SLN dissection for endometrial cancer and informed the development of a competency assessment tool. Consensus agreement identified 21 mandatory and three prohibited steps to complete a SLN dissection. The competency assessment tool was used to rate surgical quality in three preselected videos, demonstrating clear separation in the rating of the skill level displayed with mean skills summary scores differing significantly between the three videos (F score=89.4; P<0.001). Internal consistency of the items was high (Cronbach α=0.88).

CONCLUSION

Specific mandatory and prohibited steps of SLN dissection in endometrial cancer have been identified and validated based on consensus among a large number of international experts. A competency assessment tool is now available and can be used for surgeon selection in clinical trials and for ongoing, prospective quality assurance in routine clinical care.

Diagnostic performance of intraoperative assessment in grade 2 endometrioid endometrial carcinoma

Abstract

Background

Endometrial carcinoma is the most common gynecologic malignancy in developed countries. Grade 2 carcinoma is associated with pelvic lymph-node metastasis, depending on selected risk factors. Intraoperative assessment (IOA) can identify patients at risk for lymph node metastasis who should undergo staging surgery. Our objective was to establish the diagnostic precision of IOA in determining the need for surgical staging in grade 2 endometrioid endometrial carcinoma.

Methods

Two hundred twenty-two patients underwent IOA. Results were compared to the final pathology report. The accuracy of the IOA parameters was calculated. Variables were evaluated in patients with positive versus negative IOA. Overall and disease-free survivals were calculated according to IOA, lymphadenectomy, and nodal metastasis.

Results

IOA was positive in 80 patients. It showed an accuracy of 76.13% when compared with the postoperative assessment. The best individual parameter was myometrial invasion. Nodal metastasis was observed in 16 patients in the positive IOA group and 7 patients in the negative group. Patients with lymph node metastasis had a 5-year overall survival rate of 80.9%, whereas patients without metastasis had a 5-year overall survival rate of 97.9%.

Conclusions

IOA is an adequate tool to identify high-risk patients in grade 2 endometrial carcinoma. Myometrial invasion is the individual parameter that yields the highest diagnostic precision.

Incidence of pelvic lymph node metastasis using modern FIGO staging and sentinel lymph node mapping with ultrastaging in surgically staged patients with endometrioid and serous endometrial carcinoma

OBJECTIVE

We report the incidence of occult nodal metastasis in patients who underwent primary surgical staging for apparent early endometrioid or serous endometrial cancer with bilateral SLN mapping and enhanced pathology. Occult ovarian metastasis rates were also reported.

METHODS

Patients with clinical stage I serous or endometrioid endometrial cancer who underwent primary staging surgery with successful bilateral SLN mapping from 1/2005-12/2018 were retrospectively evaluated. Rates of isolated tumor cells (ITCs), micro- and macrometastatic nodal disease, and occult ovarian involvement were reported.

RESULTS

Of 1044 patients, 959 had endometrioid and 85 serous carcinoma. There were no positive SLNs among 510 patients with noninvasive FIGO grade 1/2 endometrioid carcinoma and < 1%ITCs. Grade 1: 4.5%(9/202) with inner-half and 10%(6/62) with outer-half myoinvasion had positive SLNs. Grade 2: rates were 4%(3/76) and 20%(8/41), respectively. Grade 3: 5%(1/20) with noninvasive, 3%(1/31) with inner-half, and 24%(4/17) with outer-half myoinvasion had positive SLNs. ITC incidence increased with depth of myoinvasion-25% of deeply invasive grade 1/2 and 18% of deeply invasive grade 3 tumors. Four (10%) of 41 patients with noninvasive serous endometrial carcinoma had ITCs or positive SLNs. There were no occult ovarian metastases with grades 1/2 disease, 2/68 (3%) with grade 3 disease, and 2/85 (2%) with serous endometrial carcinoma.

CONCLUSION

Ultrastaging SLNs may be unwarranted in low-grade noninvasive endometrioid cancer but valuable in noninvasive serous carcinoma. Occult ovarian metastasis is uncommon in early endometrial carcinoma and occurs in 2-3% of high-risk histologies. Further research is needed to determine ITC significance, particularly with regard to adjuvant treatment.

Sentinel lymph node mapping in endometrial cancer: performance of hysteroscopic injection of tracers

OBJECTIVE

To report on the performance of hysteroscopic injection of tracers (indocyanine green (ICG) and technetium-99m (Tc-99m)) for sentinel lymph node (SLN) mapping in endometrial cancer.

METHODS

Single-center retrospective evaluation of consecutive patients who underwent SLN mapping following hysteroscopic peritumoral injection of tracer. Detection rate (overall/bilateral/aortic) diagnostic accuracy, and oncologic outcomes were evaluated.

RESULTS

A total of 221 procedures met the inclusion criteria. Mean patient age was 60 (range 28-84) years and mean body mass index was 26.9 (range 15-47) kg/m² . In 164 cases (70.9%) mapping was performed laparoscopically. The overall detection rate of the technique was 94.1% (208/221 patients). Bilateral pelvic mapping was found in 62.5% of cases with at least one SLN detected and was more frequent using ICG than with Tc-99m (73.8% vs 53.3%; p<0.001). In 47.6% of cases SLNs mapped in both pelvic and aortic nodes, and in five cases (2.4%) only in the aortic area. In eight patients (3.8%) SLNs were found in aberrant (parametrial/presacral) areas. Mean number of detected SLNs was 3.7 (range 1-8). In 51.9% of cases at least one node other than SLNs was removed. Twenty-six patients (12.5%) had nodal involvement: 12 (46.2%) macrometastases, six (23.1%) micrometastases, and eight (30.7%) isolated tumor cells. In 12 cases (46.8%) the aortic area was involved. Overall, 6/221 (2.7%) patients had isolated para-aortic nodes. Three false-negative results were found, all in the Tc-99m group. All had isolated aortic metastases. Overall sensitivity was 88.5% (95% CI 71.7 to 100.0) and overall negative predictive value was 96.5% (95% CI 86.8 to 100.0). There were 10 (4.8%) recurrences: five abdominal/distant, four vaginal, and one nodal (in the aortic area following a unilateral mapping plus side-specific pelvic lymphadenectomy). Most recurrences (9/10 cases) were patients in whom a completion lymphadenectomy was performed. No deaths were reported after a mean follow-up of 47.7 months.

CONCLUSIONS

Hysteroscopic injection of tracers for SLN mapping in endometrial cancer is as accurate as cervical injection with a higher detection rate in the aortic area. ICG improves the bilateral detection rate. Adding lymphadenectomy to SLN mapping does not reduce the risk of relapse.

Accuracy of One-Step Nucleic Acid Amplification in Detecting Lymph Node Metastases in Endometrial Cancer

One-step nucleic acid amplification (OSNA) is used to intraoperatively detect sentinel lymph node metastases in breast cancer. OSNA has also been proposed in endometrial cancer, but evidence in this regard is unclear to define the diagnostic accuracy of OSNA in detecting lymph node metastases in endometrial cancer. A systematic review and meta-analysis was performed by searching 8 electronic databases from their inception to March 2019 for studies testing the diagnostic accuracy of OSNA in detecting sentinel lymph node metastasis in endometrial cancer. Pathologic ultrastaging was the reference standard. Sensitivity, specificity, positive and negative likelihood ratio (LR+ and LR-), diagnostic odds ratio (DOR) and area under the curve (AUC) on SROC curve were calculated. Four studies with 237 patients and 691 lymph nodes were included. OSNA showed sensitivity = 0.88, specificity = 0.93, LR + =17.95, LR- = 0.15, DOR = 191.23 and high diagnostic accuracy (AUC = 0.959). OSNA appears as a highly accurate tool for intraoperative assessment of sentinel lymph node in endometrial cancer.