Risk of empty lymph node packets in sentinel lymph node mapping for endometrial cancer using indocyanine green

Consensus on surgical technique for sentinel lymph node dissection in cervical cancer

OBJECTIVE

The purpose of this study was to establish a consensus on the surgical technique for sentinel lymph node (SLN) dissection in cervical cancer.

METHODS

A 26 question survey was emailed to international expert gynecological oncology surgeons. A two-step modified Delphi method was used to establish consensus. After a first round of online survey, the questions were amended and a second round, along with semistructured interviews was performed. Consensus was defined using a 70% cut-off for agreement.

RESULTS

Twenty-five of 38 (65.8%) experts responded to the first and second rounds of the online survey. Agreement ≥70% was reached for 13 (50.0%) questions in the first round and for 15 (57.7%) in the final round. Consensus agreement identified 15 recommended, three optional, and five not recommended steps. Experts agreed on the following recommended procedures: use of indocyanine green as a tracer; superficial (with or without deep) injection at 3 and 9 o'clock; injection at the margins of uninvolved mucosa avoiding vaginal fornices; grasping the cervix with forceps only in part of the cervix is free of tumor; use of a minimally invasive approach for SLN biopsy in the case of simple trachelectomy/conization; identification of the ureter, obliterated umbilical artery, and external iliac vessels before SLN excision; commencing the dissection at the level of the uterine artery and continuing laterally; and completing dissection in one hemi-pelvis before proceeding to the contralateral side. Consensus was also reached in recommending against injection at 6 and 12 o'clock, and injection directly into the tumor in cases of the tumor completely replacing the cervix; against removal of nodes through port without protective maneuvers; absence of an ultrastaging protocol; and against modifying tracer concentration at the time of re-injection after mapping failure.

CONCLUSION

Recommended, optional, and not recommended steps of SLN dissection in cervical cancer have been identified based on consensus among international experts. These represent a surgical guide that may be used by surgeons in clinical trials and for quality assurance in routine practice.

Accuracy of ICG compared with technetium-99 m for sentinel lymph node biopsy in vulvar cancer

PURPOSE

Sentinel lymph node biopsy with radioactive tracer is the standard-of-care in lymph node status assessment in vulvar cancer. Indocyanine green fluorescence-ICG is a promising detection method, due to its advantages over technetium-99 m. In vulvar cancer, the procedure is controversial due to study heterogeneity and the small sample size in previous studies. This study evaluates ICG sentinel lymph node detection compared with the criterion-standard with technetium (dual modality method).

METHODS

Preoperative technetium and intraoperative ICG for sentinel lymph node have been prospectively evaluated in early-stage vulvar cancer. The primary endpoint was to determine accuracy in the detection rate for ICG compared with technetium. Secondary objectives included tracer modality relationship with obesity, tumor size and location.

RESULTS

In total, 75 patients participated at 8 centers; 38 had lateral and 37 had midline vulvar tumors. The overall sentinel lymph node detection rate was 85.3 % for technetium and 82.7 % for ICG. For lateral tumors, the detection rate was 84.2 % vs. 89.5 %, while it was 86.5 % vs. 75.7 % for middle tumors, using technetium and ICG, respectively. The median sentinel node harvest was 1.7 (range 1-4), with 24 % metastatic involvement. The sensitivity and positive predictive value for ICG based on the standard technique with technetium was 91.08 % (95 % CI, 83.76-95.84) and 94.8 % (95 % CI, 84.84-96.48), respectively. No significant differences were found comparing the two tracers in patients with midline lesions, obesity (body mass index ≥ 30) and tumor size ≥ 2-4 cm.

CONCLUSION(S)

ICG shows comparable performance parameters to the gold-standard of radioisotope localization.

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.

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.

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.

Preoperative SPECT/CT + intraoperative CT fusion enabling surgical augmented reality to target sentinel lymph node in endometrial cancer

Purpose

To establish a proof-of-concept study using a phantom model to allow the fusion of preoperative single-photon emission computed tomography (SPECT) combined with computed tomography (CT), also known as SPECT/CT, with intraoperative CT, enabling the application of an augmented reality (AR) surgical guidance system for pelvic sentinel lymph node (SLN) detection in endometrial cancer patients.

Methods

A three-dimensional (3D) pelvic phantom model printed in a gelatin-based scaffold including a radiopaque pelvis, a vascular tree mimicking the iliac vessels, two 3D-printed fillable spheres representing the target pelvic sentinel lymph nodes, and a calibration board was developed. A planar with SPECT/CT lymphoscintigraphy and CT were performed independently on the model. We performed all the necessary steps to achieve the fusion between SPECT/CT and CT. Then, we performed a laparoscopy of the pelvic anatomy on the phantom model to assess in real time the overlay of the recording on the anatomical structures and AR guidance system performance.

Results

We have successfully completed all the steps needed to fuse the two imaging procedures. This allowed us to apply, in real time, our surgical guidance system with the coverage rate of the visible surface by the augmented reality surface, respectively, on the left SLN 99.48% and on the right SLN 99.42%.

Conclusion

Co-registration and real-time fusion between a preoperative SPECT/CT and intraoperative CT are feasible. The metric performance of our guidance system is excellent in relation to possible SPECT/CT and CT fusion. Based on our results, we are able to translate the technology to patients, and we initiated a clinical study to evaluate the accuracy of the AR guidance system for endometrial cancer surgery, with a correlation with indocyanine green (ICG)-based technique, representing the gold standard today in the intraoperative detection of SLN in endometrial cancers, despite various limitations.

Lymphatic Mapping and Sentinel Node Biopsy in High-Grade Uterine Cancers

PURPOSE OF REVIEW

Sentinel lymph node (SLN) mapping has been adopted as an acceptable method of lymph node evaluation in the surgical staging for low-grade endometrial cancer. In this review, we analyze the literature on the utility of SLN mapping in high-grade endometrial cancer.

RECENT FINDINGS

SLN mapping in high-grade endometrial cancer demonstrates similar high detection rates and diagnostic accuracy as seen in low-grade endometrial cancers. However, obtaining sufficient operator experience (at least 30 cases) and following SLN mapping algorithm continues to be essential to preserving diagnostic accuracy. Although limited in retrospective study design and short-term follow-up, current studies have not demonstrated inferior survival outcomes of SLN mapping compared to traditional lymphadenectomy. SLN mapping is an acceptable and accurate method of lymph node evaluation in high-grade endometrial cancer. Future prospective studies are needed to evaluate long-term oncologic outcomes between SLN mapping and systematic lymphadenectomy in this patient population.

Comparison of Different Near-Infrared Technologies to Detect Sentinel Lymph Node in Uterine Cancer: A Prospective Comparative Cohort Study

OBJECTIVES

Sentinel lymph node biopsy is considered a crucial step in endometrial cancer staging. Cervical injection has become the most favored technique and indocyanine green has been demonstrated to be more accurate than other tracers. Different near-infrared camera systems are currently being used to detect indocyanine green in sentinel lymph nodes and have been compared in different patients. The present study aimed to determine the number and site of sentinel lymph nodes detected in the same patients with two different near-infrared technologies.

METHODS

This is a prospective, single-center, observational, non-sponsored study. Patients with presumed uterine-confined endometrial cancer were prospectively enrolled. After cervical injection, two different near-infrared cameras were used to detect sentinel lymph nodes at the same time: Olympus, Tokyo, Japan-considered the standard (SNIR); and Medtronic, Minneapolis, MN, USA with VISION SENSE^® which is a new laser near-infrared (LNIR) fluorescence laparoscope. The two cameras were alternatively switched on to detect sentinel lymph nodes in the same patients.

RESULTS

Seventy-four consecutive patients were included in the study. Most of the patients were diagnosed with endometrioid histology (62, 83.8%), FIGO stage IA (48, 64.9%), grade 2 (43, 58.1%), and underwent surgery with laparoscopic approach (70, 94.0%). The bilateral detection rate was 56/74 (75.7%) with SNIR and 63/74 (85.1%) with LNIR (p = 0.214). The total number of sentinel lymph nodes identified in the left hemipelvis was 65 and 70 with SNIR and LNIR, respectively; while in the right hemipelvis, there were 74 and 76, respectively. The median number of sentinel lymph nodes identified with SNIR and LNIR was 2 (range, 0-4) and 2 (range, 0-4), respectively (p = 0.370). No difference in site of sentinel lymph node detection was evident between the two technologies (p = 0.994). Twelve patients (16.2%) had sentinel lymph node metastasis: in all cases metastatic sentinel lymph nodes were detected both with Olympus and LNIR.

CONCLUSIONS

No difference in bilateral detection rate and number or site of sentinel lymph node detection was evident comparing two different technologies of near-infrared camera for ICG detection in endometrial cancer patients. No difference in sentinel lymph node metastases identification was detected between the two technologies.

A large multicenter propensity match study of sentinel lymph node biopsy feasibility in endometrioid variants of endometrial cancer

INTRODUCTION

Sentinel lymph node (SLN) biopsy algorithm has been routinely applied in all endometrial endometrioid tumors, however, no studies analyzed the feasibility of SLN mapping in endometrioid variants (EV), which included villoglandular, secretory, ciliated cell, mucinous, and squamous differentiation. This study aimed to demonstrate the feasibility of SLN biopsy in EV of EC.

MATERIALS AND METHODS

All patients undergoing minimally invasive surgical treatment for early-stage EC were included in the study. Patients were divided into 2 study groups: Group 1 which included patients with EV, and Group 2 which included patients with typical endometrioid histology. A propensity match analysis was performed according to age (≥65 years vs. no), BMI (≥30 kg/m² vs. no), and LVSI (present vs. absent).

RESULTS

After a 1:5 propensity-matched analysis, a total of 458 patients were identified (Group 1 n = 77, Group 2 n = 381). Overall detection rate was not statistically significant between the EV and the typical endometrioid group (94.8% vs. 92.4%, p = 0.319). Furthermore, neither bilateral nor unilateral detection rate was different between the two groups (70.1% vs. 74.8%, p = 0.267, and 23.4% vs. 17.8%, p = 0.120). BMI ≥30 kg/m² was the only factor influencing SLN failure (p = 0.013). SLN technique showed excellent sensitivity in both the EV (100% sensitivity, p < 0.001) and the typical endometrioid unit (93.8% sensitivity, p < 0.001).

CONCLUSION

SLN research/detection for EV of endometrial cancer is a feasible and highly sensitive technique. Obesity was confirmed to be a risk factor for SLN failure.

Detection of the sentinel lymph node with hybrid tracer (ICG-[99mTc]Tc-albumin nanocolloid) in intermediate- and high-risk endometrial cancer: a feasibility study

PURPOSE

Indocyanine green (ICG) is frequently used for the detection of the sentinel lymph node (SLN) in gynecology, but it carries the loss of the presurgical SLN mapping provided by [^99mTc]-based colloids. Hybrid tracers such as ICG-[^99mTc]Tc-albumin nanocolloid combine the benefits of both components. The aim of this study was to evaluate the feasibility and applicability of this hybrid tracer injected by transvaginal ultrasound-guided myometrial injection of radiotracer (TUMIR) approach in the detection of SLNs in patients with intermediate- and high-risk EC.

METHODS

Fifty-two patients with intermediate- and high-risk EC underwent SLN biopsy after injection of a hybrid tracer using the TUMIR approach, followed by pelvic and paraaortic lymphadenectomy. SLNs were detected preoperatively by lymphoscintigraphic study and intraoperatively by gamma probe and near-infrared (NIR) optical laparoscopic camera.

RESULTS

Preoperative lymphatic drainage was obtained in 69% and intraoperative detection in 71.4% of patients. A total of 146 SLNs (4.17 SLNs/patient) were biopsied. Pelvic bilateral detection was observed in 57% of the women and paraaortic drainage in 34% of the patients. The radioactive component allowed the detection of SLN in 97.1% of the patients, while the fluorescent component detected 80%. In more than 17% of the patients with intraoperative detection, SLNs were detected only by the radioactive signal. Lymph node metastasis was identified in 14.3% of patients submitted to SLNB. The sensitivity and negative predictive value for metastatic involvement were 100%.

CONCLUSION

TUMIR injection of a hybrid tracer in patients with intermediate- and high-risk EC combines the benefits of the radiotracer and the fluorescence methods with a single tracer. The method increases the paraaortic detection rate and allows a potential increase in SLN detection. Notwithstanding, based on our findings, the radioactive component of the hybrid tracer cannot be obviated.

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.

Advances in management of nonendometrioid endometrial carcinoma, with an emphasis on the sentinel lymph node technique

PURPOSE OF REVIEW

During the last few years there have been important advances in our understanding of endometrial cancer biology, staging, and therapy. In this article, we discuss updates and controversies in the treatment of nonendometrioid endometrial carcinoma (non-EEC), with an emphasis on the role of sentinel lymph node (SLN) biopsy.

RECENT FINDINGS

Lymph node involvement is an important factor in determining prognosis and guiding adjuvant therapy in endometrial carcinoma. SLN biopsy has emerged as a less morbid alternative to lymphadenectomy in surgical staging, and it has generally gained acceptance in the setting of low-grade endometrial carcinoma; however, its role in the setting of high-grade disease remains a topic of debate. Several prospective studies have demonstrated the accuracy of SLN biopsy in detecting nodal metastasis in high-grade endometrial carcinoma. Retrospective series have compared oncologic outcomes of patients with high-grade disease, surgically staged by SLN biopsy, to those staged with lymphadenectomy, and have reported similar survival outcomes. Prospective data on survival is lacking.

SUMMARY

Currently, there is sufficient data to support the diagnostic accuracy of SLN biopsy in the surgical staging of non-EEC. The retrospective evidence demonstrates similar survival for SLN biopsy versus lymphadenectomy.

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.

Cervical re-injection of indocyanine green to improve sentinel lymph node detection in endometrial cancer

OBJECTIVES

To evaluate the role of cervical re-injection of indocyanine green (ICG) to increase the detection rate of sentinel lymph node (SLN) in patients with endometrial cancer (EC) who underwent robotic-assisted surgical staging.

METHODS

We retrospectively identified consecutive EC patients undergoing robotic-assisted staging with SLN biopsy at our Institution between June 2016 and April 2020. Patients were excluded if they had open abdominal surgical approach, neoadjuvant chemotherapy, and advanced stage [International Federation of Gynecology and Obstetrics (FIGO) stage III-IV] at diagnosis. According to our SLN protocol, in case of either unilateral or no SLN detection, we performed an ipsilateral or bilateral cervical re-injection of ICG.

RESULTS

In total, 251 patients meeting inclusion criteria were included in the analysis. At first injection, bilateral detection was achieved in 184 (73.3%), unilateral detection in 57 (22.7%), and no detection in 10 (4.0%) patients. Cervical re-injection was performed in 51 of 67 patients with failed bilateral mapping. After cervical re-injection, bilateral detection rate increased to 94.5% (222/235), while unilateral and no detection were 5.1% (12/235) and 0.4% (1/235), respectively.

CONCLUSIONS

Our results suggest that cervical re-injection of ICG, in case of failed bilateral mapping of SLN, brings about a significant improvement in SLN detection rates, therefore reducing the number of side-specific required lymphadenectomies.

A cost-effectiveness analysis of three approaches for lymph node assessment in patients with low- and intermediate-risk endometrial cancer

OBJECTIVE

To assess the cost-effectiveness of sentinel lymph node mapping compared to risk factor assessment and routine full lymph node dissection for the assessment of lymph nodes in patients with low- and intermediate-risk endometrioid endometrial cancer.

METHODS

A decision-analytic model was designed to compare three lymph node assessment strategies in terms of costs and effects: 1) sentinel lymph node mapping; 2) post-operative risk factor assessment (adjuvant therapy based on clinical and histological risk factors); 3) full lymph node dissection. Input data were derived from systematic literature searches and expert opinion. QALYs were used as measure of effectiveness. The model was built from a healthcare perspective and the impact of uncertainty was assessed with sensitivity analyses.

RESULTS

Base-case analysis showed that sentinel lymph node mapping was the most effective strategy for lymph node assessment in patients with low- and intermediate-risk endometrial cancer. Compared to risk factor assessment it was more costly, but the incremental cost effectiveness ratio stayed below a willingness-to-pay threshold of €20,000 with a maximum of €9637/QALY. Sentinel lymph node mapping was dominant compared to lymph node dissection since it was more effective and less costly. Sensitivity analyses showed that the outcome of the model was robust to changes in input values. With a willingness-to-pay threshold of €20,000 sentinel lymph node mapping remained cost-effective in at least 74.3% of the iterations.

CONCLUSION

Sentinel lymph node mapping is the most cost-effective strategy to guide the need for adjuvant therapy in patients with low and intermediate risk endometrioid endometrial cancer.

Diagnostic value of indocyanine green fluorescence guided sentinel lymph node biopsy in vulvar cancer: A systematic review

INTRODUCTION

Sentinel lymph node biopsy (SLN) helps define lymph node status, a major prognostic factor in vulvar cancer. The aim of the current systematic review was to assess the use of indocyanine green (ICG) coupled with near-infrared (NIR) fluorescence imaging in SLN mapping in vulvar cancer in terms of technique used, feasibility and accuracy.

DATA SOURCES

We performed a systematic review using bibliographic citations from PubMed, Clinical Trials.gov, Embase, Cochrane Library, and Web of Science databases. MeSH terms for SLN, ICG and vulvar cancer were combined and restricted to the English language. The final search was performed on May 28, 2020. The primary outcome was to determine if the use of ICG alone in detecting SLN in women with vulvar cancer is as accurate as the gold standard dual labeling technique.

RESULTS

Of the 34 studies initially identified, 13 were included for analysis. The SLN detection rate with ICG and NIR fluorescence ranged from 89.7 to 100%. No studies demonstrated the superiority of other detection techniques compared to ICG and NIR imaging. Lower SLN detection rates were found in studies with the most metastatic lymph nodes. No consensus was reached concerning the optimal use of ICG in terms of: injection timing or site; concentrations or volume of ICG; or use of human serum albumin or hybrid tracer. No adverse events were reported.

CONCLUSION

ICG for SLN mapping appears to be safe in women with vulvar cancer with a detection rate similar to the current techniques. A large prospective randomized controlled study with optimization of the technique is necessary to homogenize current practice and determine the true value of ICG in vulvar cancer.

PROSPERO ID

CRD42020178261.

Patients' and gynecologists' views on sentinel lymph node mapping in low- and intermediate-risk endometrial cancer: a Dutch vignette study

OBJECTIVE

Sentinel lymph node (SLN) mapping in endometrial cancer is gaining ground. However, patient views on this new technique are unknown. The aim of this study was to determine factors important to patients and gynecologists when considering SLN mapping in low- and intermediate-risk endometrial cancer.

METHODS

We performed a vignette study. Patients who underwent a total hysterectomy for low- or intermediate-risk endometrial cancer between 2012 and 2015 were invited. Dutch gynecologists specializing in gynecologic oncology were also invited. We based the selection for attributes in the vignettes on literature and interviews: risk of complications of SLN mapping; chance of finding a metastasis; survival gain; risk of complications after radiotherapy; operation time; and hospital of surgery (travel time). We developed a questionnaire with 18 hypothetical scenarios. Each attribute level varied and for each scenario, participants were asked how strongly they would prefer SLN on a scale from 1 to 7. The strength of preference for each scenario was analyzed using linear mixed effects models.

RESULTS

A total of 38% of patients (41/108) and 33% of gynecologists (42/126) participated in the study. Overall, they had a preference for SLN. The mean preference for patients was 4.29 (95% CI 3.72 to 4.85) and 4.39 (95% CI 3.99 to 4.78) for gynecologists. Patients' preferences increased from 3.4 in the case of no survival gain to 4.9 in the case of 3-year survival gain (P<0.05) and it decreased when travel time increased to >60 min (-0.4, P=0.024), or with an increased risk of complications after adjuvant radiotherapy (-0.6, P=0.002). For gynecologists all attributes except travel time were important.

CONCLUSIONS

Overall, patients and gynecologists were in favor of SLN mapping in low- and intermediate-risk endometrial cancer. Most important to patients were survival gain, travel time, and complication risk after adjuvant radiotherapy. These preferences should be taken into account when counseling about SLN mapping.

Technetium-99m-indocyanine green versus technetium-99m-methylene blue for sentinel lymph node biopsy in early-stage endometrial cancer

INTRODUCTION

The low accuracy of pre-operative imaging techniques for prediction of nodal status strengthens the relevance of sentinel lymph node (SLN) biopsy in endometrial cancer, although the optimal method for its detection is still under investigation. The increasing use of indocyanine green (ICG) has aroused concern about its enhanced visualization of lymphatic channels, which could lead to a specimen that is thought to be nodal tissue not subsequently yielding a lymph node on pathologic analysis ('empty node packet'). Our main objective was to compare the overall and bilateral detection rates for SLN biopsy using two combined techniques: technetium-99m-ICG (Tc-99m-ICG) versus technetium-99m-methylene blue (Tc-99m-MB). Our secondary aim was to compare the 'empty node packet' rates between the two cohorts.

METHODS

A prospective, non-randomized, single-center trial including patients diagnosed with endometrial cancer (any grade or histology) in pre-operative early stage, and operated on between February 2017 and July 2019. All tracers were injected intracervically. Pelvic and aortic lymphadenectomy were performed on patients at intermediate or high risk of recurrence pre-operatively. All SLNs were sent for intra-operative frozen section and afterwards processed following an ultrastaging protocol.

RESULTS

Eighty-four patients were included, 58% (n=49) in the Tc-99m-MB group and 42% (n=35) in the Tc-99m-ICG group. Overall detection rate was 93% and was not statistically different between the two groups. A better bilateral detection rate was observed among Tc-99m-ICG patients (69% vs 41%, p=0.012). The 'empty node packet' rate was 4% in the Tc-99m-ICG cohort and 0% in the Tc-99m-MB cohort (p=0.032).

DISCUSSION

Tc-99m-ICG is a feasible, safe technique for SLN biopsy in early-stage endometrial cancer, and appears to be superior in terms of bilateral detection to Tc-99m-MB. The addition of Tc-99m to ICG could decrease the rate of 'empty node packets' and better define the anatomic location of SLNs in patients with endometrial cancer.

Defining the learning curve for successful staging with sentinel lymph node biopsy for endometrial cancer among surgeons at an academic institution

BACKGROUND

Sentinel lymph node (SLN) biopsy is increasingly used in endometrial cancer staging; however, success of the technique is variable, and the learning curve needs to be better understood. Success is defined as identification of a SLN specimen containing nodal tissue in bilateral hemi-pelvises.

OBJECTIVE

To assess the learning curve of surgeons at an academic institution in performing successful SLN mapping and biopsy during robotic staging for endometrial cancer.

METHODS

After institutional review board approval, patients who underwent staging with robotic SLN mapping using indocyanine green at a single academic program between July 2012 and December 2017 were identified. Demographic, pathologic, and surgical data were retrospectively collected from the medical records. Descriptive and comparative statistics were performed. Surgeon rates of successful bilateral SLN mapping and removal of lymphoid-containing SLN specimens were compared. A logistic model was used to analyze the probability of successful SLN mapping and removal of lymph node-containing tissue with increasing number of procedures performed.

RESULTS

Three hundred and seventeen patients met the eligibility criteria. Most had early-stage, low-grade endometrial cancer. A total of 194 (61%) patients had successful bilateral mapping. Among seven surgeons, a plateau in rates of successful bilateral mapping was achieved after 40 cases. No linear correlation was seen between the number of surgeries performed and the rate of removal of lymph node-containing tissue among surgeons. Each additional 10 procedures performed was associated with a 5% and an 11% increase in the odds of successful SLN mapping and removal of lymph node-containing tissue, respectively.

DISCUSSION

The successful removal of lymph node-containing specimens appears to be a surgeon-specific phenomenon. The plateau of the learning curve for successful bilateral mapping seems to be reached at around 40 cases. These first 40 cases offer a time for auditing of individual rates of SLN mapping and removal to identify surgeons who may benefit from procedure-specific remediation.