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

Comparison of different tracers in sentinel lymph node detection for endometrial cancer: a systematic review and network meta-analysis

BACKGROUND

In the realm of endometrial cancer (EC) therapeutics and prognostic assessments, lymph nodes' status is paramount. The sentinel lymph node (SLN) detection, recognized for its reliability, has been progressively adopted as a standard procedure, posing a compelling alternative to conventional systematic lymphadenectomy. However, there remains a lack of agreement on the most effective choice of tracers for this procedure.

OBJECTIVE

This investigation was dedicated to a comparative analysis of various tracers to identify the most effective combination that achieves the highest detection rate. This endeavor sought to enhance the efficacy of SLN biopsy in the surgical management of EC.

METHODS

A systematic review was conducted across multiple databases, including the Cochrane Central Register of Controlled Trials, PubMed, Web of Science, Embase, and clinicaltrials.gov, to analyze studies employing different tracers for SLN biopsy during surgery in EC. Using Bayesian network meta-analysis, the authors compared the total and bilateral detection rates of various tracers.

RESULTS

After screening 1431 articles, 11 studies, including 2699 participants, were selected in this network meta-analysis. The combination of radioactive isotopes and indocyanine green (ICG) emerged as the most efficacious method in total and bilateral detection rates, with the Surface Under the Cumulative Ranking Curve (SUCRA) scores of 80.00 and 86.36%, respectively. Additionally, carbon nanoparticles (CNPs) demonstrated superior performance in the detection of para-aortic lymph nodes with an SUCRA score of 97.77%.

CONCLUSION

Network meta-analysis shows that the application of radioactive isotopes and ICG is the optimal tracer combination for SLN biopsy during surgery in EC.

Link between isolated para-aortic lymph node metastasis and intrauterine cancer site in early stage endometrial cancer

OBJECTIVE

Missing occult para-aortic lymph node metastasis is one of the primary concerns of sentinel lymph node biopsy in endometrial cancer. Our study aimed to evaluate the relationship between intrauterine cancer site and isolated para-aortic lymph node metastasis to tailor treatment and reduce the false negative rate of the sentinel lymph node procedure.

METHODS

A retrospective, multicenter, case control study was performed in four international centers. All patients with positive lymph nodes who had complete surgical staging with pelvic and para-aortic lymphadenectomy, between January 2013 and December 2023, were included. Detailed descriptions of the cancer location within the uterine cavity on the cranio-caudal plane and the myometrial wall involvement on the cranio-caudal and ventro-dorsal planes were collected, as were clinical data and cancer histological features. Patients with isolated para-aortic lymph node metastasis were allocated to group 1; patients with pelvic lymph node metastasis and those with both pelvic and para-aortic lymph node metastasis were allocated to group 2. The groups were compared according to the variables collected.

RESULTS

200 preoperative early stage endometrial cancer patients with postoperative International Federation of Gynecology and Obstetrics 2009/2023 stage IIIC1/IIIC2 were included in our study: 42 patients (21%) with isolated para-aortic lymph node metastasis were allocated to group 1 and the remaining patients to group 2. The two groups had comparable clinical and pathological characteristics (p>0.05): mean age was 66.5±10.3 (group 1) and 63.5±11.9 (group 2); endometrioid histotype was the predominant one for both groups (50%); most patients had myometrial infiltration >50% (80.9% and 79.7%), grade 3 (61.9% and 63.9%), and lymph vascular space invasion (78.5% and 82.2%). Cancers involving the fundal uterine cavity, the fundal myometrial wall, or the anterior myometrial wall were 3.11 (1.04-9.27), 3.03 (1.12-8.21), and 2.12 (0.77-5.80) times more likely to metastasize only to para-aortic lymph nodes compared with cancers located in other uterine sites.

CONCLUSIONS

In this study, the intrauterine location of the cancer determined the site of lymph node metastasis. When the tumor involved the fundus (cavity or wall) and infiltrated exclusively the anterior wall, the baseline risk of spreading only into the para-aortic area increased significantly in selected patients at risk of nodal disease.

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.

Optimizing Outcomes through a Multidisciplinary Team Approach in Endometrial Cancer

This study aimed to assess the impact of a multidisciplinary team (MDT) approach on outcomes with endometrial cancer (EC) patients, utilizing 2013-2020 data from the Reggio Emilia Cancer Registry. Recurrence rate, treatments, and outcome indicators were compared between the MDT (319 cases) and non-MDT (324 cases) groups. Among 643 cases, 52.4% were over 65 years old, 98% had microscopic confirmation, and 73% were in stage I. Surgery was performed in 89%, with 41% receiving adjuvant therapies. Recurrence rates (10%) were similar between the two groups, but MDT patients who were older and predominantly in stage I exhibited 79% recurrence within one year (21% in the non-MDT group). Disease-free survival (DFS) showed no significant difference [HR 1.1; 95% CI 0.7-1.6], while differences in overall survival (OS) were notable [HR 1.5; 95% CI 1.0-2.4]. The 5-year OS rates were 87% and 79% in the MDT and non-MDT groups. Comparing the 2013-2015 to 2016-2020 study periods, a shift towards caring for older women, more advanced-stage patients, and those residing outside the metropolitan area, along with a greater number of relapsed cases (from 16% to 76%), were accounted for. These findings underscore the impact of an MDT on EC outcomes, highlighting the evolving patient demographics over time.

Enhancing the Accuracy of Lymph-Node-Metastasis Prediction in Gynecologic Malignancies Using Multimodal Federated Learning: Integrating CT, MRI, and PET/CT

Gynecological malignancies, particularly lymph node metastasis, have presented a diagnostic challenge, even with traditional imaging techniques such as CT, MRI, and PET/CT. This study was conceived to explore and, subsequently, to bridge this diagnostic gap through a more holistic and innovative approach. By developing a comprehensive framework that integrates both non-image data and detailed MRI image analyses, this study harnessed the capabilities of a multimodal federated-learning model. Employing a composite neural network within a federated-learning environment, this study adeptly merged diverse data sources to enhance prediction accuracy. This was further complemented by a sophisticated deep convolutional neural network with an enhanced U-NET architecture for meticulous MRI image processing. Traditional imaging yielded sensitivities ranging from 32.63% to 57.69%. In contrast, the federated-learning model, without incorporating image data, achieved an impressive sensitivity of approximately 0.9231, which soared to 0.9412 with the integration of MRI data. Such advancements underscore the significant potential of this approach, suggesting that federated learning, especially when combined with MRI assessment data, can revolutionize lymph-node-metastasis detection in gynecological malignancies. This paves the way for more precise patient care, potentially transforming the current diagnostic paradigm and resulting in improved patient outcomes.

Robotic para-aortic sentinel lymph node mapping in endometrial, cervical, and ovarian cancer

The concept of pelvic sentinel lymph node mapping has been well-investigated in endometrial and cervical cancer. A variety of tracers have been used including blue dye, technetium-99-m (Tc-99 m), and fluorescent tracer indocyanine green. Pelvic sentinel lymph node mapping has shown its safety, efficacy, and diagnostic accuracy, with high sensitivity and negative predictive value of more than 90%, in retrospective cohort studies as well as in prospective trials for robotic surgery. The concept of pelvic sentinel lymph node biopsy has been incorporated in several international guidelines in early-stage endometrial cancer and a subgroup of early-stage cervical cancer, although survival data are still needed to confirm its standard use. The application of para-aortic sentinel lymph node mapping is still in a development phase, but its detection rate and diagnostic accuracy seem to be promising in initial studies. Here, an overview is given of the recent developments in the different methodologies used for identifying para-aortic sentinel lymph nodes in endometrial, cervical, and ovarian cancer.

Comparison of two hybrid sentinel node tracers: indocyanine green (ICG)-99mTc-nanocolloid vs. ICG-99mTc-nanoscan from a nuclear medicine and surgical perspective

BACKGROUND

Lymph node (LN) metastasis is a relevant predictor for survival in patients with a.o. penile cancer (PeCa), malignant melanoma. The sentinel node (SN) procedure comprises targeted resection of the first tumour-draining SNs. Here, the hybrid tracer indocyanine green (ICG)-99mTc-nanocolloid has been used for several years to combine optical and nuclear detection. Recently, the resource of the nanocolloid precursor stopped production and the precursor was replaced by a different but chemically comparable colloid, nanoscan. Our aim was to study the performance of ICG-99mTc-nanoscan compared to ICG-99mTc-nanocolloid from a nuclear and surgical perspective.

METHODS

Twenty-four patients with either PeCa or head-and-neck (H&N) melanoma and scheduled for a SN procedure were included. The initial group (n = 11) received ICG-99mTc-nanocolloid until no longer available; the second group (n = 13) received ICG-99mTc-nanoscan. Tracer uptake was assessed on lymphoscintigraphy and single-photon emission (SPECT). Intraoperatively, SNs were identified using gamma tracing and fluorescence imaging. Ex vivo (back-table) measurements were conducted to quantify the fluorescence emissions. Chemical analysis was performed to compare the ICG assembly on both precursors.

RESULTS

The mean tracer uptake in the SNs was similar for ICG-99mTc-nanocolloid (2.2 ± 4.3%ID) and ICG-99mTc-nanoscan (1.8 ± 2.6%ID; p = 0.68). 3 SNs (interquartile range (IQR) 3-4) were detected on lymphoscintigraphy in PeCa patients receiving ICG-99mTc-nanoscan compared to 2 SNs (IQR 2-3) in PeCa patients receiving ICG-99mTc-nanocolloid (p = 0.045), no differences were observed in H&N patients. Back-table measurements of resected SNs revealed a lower total fluorescence intensity in the ICG-99mTc-nanoscan group (24*109 arbitrary units (A.U) IQR 1.6*109-14*109 in the ICG-99mTc-nanocolloid group versus 4.6*109 A.U. IQR 2.4*109-42*109 in the ICG-99mTc-nanoscan group, p = 0.0054). This was consistent with a larger degree of "stacked" ICG observed in the nanoscan formulation. No tracer-related adverse events were reported.

CONCLUSIONS

Based on this retrospective analysis, we can conclude that ICG-99mTc-nanoscan has similar capacity for SN identification as ICG-99mTc-nanocolloid and can safely be implemented in SN procedures.

Applications and Safety of Sentinel Lymph Node Biopsy in Endometrial Cancer

Lymph node status is important in predicting the prognosis and guiding adjuvant treatment in endometrial cancer. However, previous studies showed that systematic lymphadenectomy conferred no therapeutic values in clinically early-stage endometrial cancer but might lead to substantial morbidity and impact on the quality of life of the patients. The sentinel lymph node is the first lymph node that tumor cells drain to, and sentinel lymph node biopsy has emerged as an acceptable alternative to full lymphadenectomy in both low-risk and high-risk endometrial cancer. Evidence has demonstrated a high detection rate, sensitivity and negative predictive value of sentinel lymph node biopsy. It can also reduce surgical morbidity and improve the detection of lymph node metastases compared with systematic lymphadenectomy. This review summarizes the current techniques of sentinel lymph node mapping, the applications and oncological outcomes of sentinel lymph node biopsy in low-risk and high-risk endometrial cancer, and the management of isolated tumor cells in sentinel lymph nodes. We also illustrate a revised sentinel lymph node biopsy algorithm and advocate to repeat the tracer injection and explore the presacral and paraaortic areas if sentinel lymph nodes are not found in the hemipelvis.

Therapeutic Benefit of Systematic Lymphadenectomy in Node-Negative Uterine-Confined Endometrioid Endometrial Carcinoma: Omission of Adjuvant Therapy

Simple Summary

Endometrial cancer is the most common gynecological tract malignancy in developed countries. Extrauterine disease, in particular lymph node metastasis, is an important prognostic factor. Nevertheless, pelvic lymphadenectomy is not considered to have a therapeutic benefit, as it did not improve survival in randomized studies. However, lymphadenectomy may have a therapeutic benefit if adjuvant therapy can be omitted without decreasing oncological outcomes, as the long-term quality of life is maintained by avoiding morbidities associated with adjuvant therapy. In intermediate- and high-risk endometrioid endometrial carcinomas, adjuvant therapy may be safely omitted without decreasing long-term survival by open surgery including systematic pelvic and para-aortic lymphadenectomy when patients are node-negative. Systematic lymphadenectomy may remove undetectable low-volume lymph node metastasis in both pelvic and para-aortic regions, and open surgery may reduce vaginal recurrence even without vaginal brachytherapy. However, lymphadenectomy may not improve survival in elderly patients and patients with p53-mutant tumors.

Abstract

Endometrial cancer is the most common gynecological tract malignancy in developed countries, and its incidence has been increasing globally with rising obesity rates and longer life expectancy. In endometrial cancer, extrauterine disease, in particular lymph node metastasis, is an important prognostic factor. Nevertheless, pelvic lymphadenectomy is not considered to have a therapeutic benefit, as it did not improve survival in randomized studies. However, lymphadenectomy may have a therapeutic benefit if adjuvant therapy can be omitted without decreasing oncological outcomes, as the long-term quality of life is maintained by avoiding morbidities associated with adjuvant therapy. In intermediate- and high-risk endometrioid endometrial carcinomas, adjuvant therapy may be safely omitted without decreasing long-term survival by open surgery including systematic pelvic and para-aortic lymphadenectomy when patients are node-negative. Systematic lymphadenectomy may remove undetectable low-volume lymph node metastasis in both pelvic and para-aortic regions, and open surgery may reduce vaginal recurrence even without vaginal brachytherapy. However, lymphadenectomy may not improve survival in elderly patients and patients with p53-mutant tumors. In this review, I discuss the characteristics of lymph node metastasis, the methods of lymph node assessment, and the therapeutic benefits of systematic lymphadenectomy in patients with intermediate- and high-risk endometrioid endometrial carcinoma.