Risk factors for failure of bilateral sentinel lymph node mapping in early-stage cervical cancer

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.

A preoperative nomogram predicting risk of lymph node metastasis for early-stage cervical cancer

OBJECTIVE

This study aimed to develop a preoperative nomogram based on clinical and pathological characteristics to provide a more individualized and accurate estimation of lymph node metastasis (LNM) in patients with early-stage cervical cancer.

METHODS

A total of 7,349 early-stage cervical cancer patients with pathologically confirmed between 1988 and 2015 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. All the patients were divided into training (n = 5,500) and validation (n = 1,849) cohorts randomly. A cohort of 455 patients from multicenter was used for the external validation. We established a multivariate logistic regression model based on preoperative clinicopathological data, from which a nomogram was developed and validated. A predicted probability of LNM < 5% was defined as low risk.

RESULTS

From multivariate logistic regression analysis, age at diagnosis, histologic subtype, tumor grade, tumor size and FIGO stage were identified as preoperative independent risk factors of LNM. The nomogram incorporating these factors demonstrated good discrimination and calibration (concordance index = 0.723; 95% confidence interval (CI), 0.707-0.738). In the validation cohort, the discrimination accuracy was 0.745 (95% CI, 0.720-0.770) and 0.747 (95% CI, 0.690-0.804), respectively. The nomogram was well calibrated with a high concordance probability. We also established an R-enabled Internet browser for LNM risk assessment, which tool may be convenient for physicians.

CONCLUSIONS

We developed an effective preoperative nomogram based on clinical and pathological characteristics to predict LNM for early-stage cervical cancer. This model could improve clinical trial design and help physicians to decide whether to perform lymphadenectomy or not.

Predictors of Non-Sentinel Lymph Node Metastasis in Patients with Positive Sentinel Lymph Node in Early-Stage Cervical Cancer: A SENTICOL GROUP Study

BACKGROUND

The goal of this study was to identify the risk factors for metastasis in the remaining non-sentinel lymph nodes (SLN) in the case of positive SLN in early-stage cervical cancer.

METHODS

An ancillary analysis of two prospective multicentric databases on SLN biopsy for cervical cancer (SENTICOL I and II) was performed. Patients with early-stage cervical cancer (FIGO 2018 IA to IIA1), with bilateral SLN detection and at least one positive SLN after ultrastaging, were included.

RESULTS

405 patients were included in SENTICOL I and Il. Fifty-two patients had bilateral SLN detection and were found to have SLN metastasis. After pelvic lymphadenectomy, metastatic involvement of non-SLN was diagnosed in 7 patients (13.5%). Patients with metastatic non-SLN were older (51.9 vs. 40.8 years, p = 0.01), had more often lympho-vascular space invasion (LVSI) (85.7% vs. 35.6%, p = 0.03), and had more often parametrial involvement (42.9% vs. 6.7%, p = 0.003). Multivariate analysis retained age (OR = 1.16, 95% IC = [1.01-1.32], p = 0.03) and LVSI (OR = 25.97, 95% IC = [1.16-582.1], p = 0.04) as independently associated with non-SLN involvement.

CONCLUSIONS

Age and LVSI seemed to be predictive of non-SLN metastasis in patients with SLN metastasis in early-stage cervical cancer. Larger cohorts are needed to confirm the results and clinical usefulness of such findings.

The lymphatic system of the uterine cervix: towards a more precise definition of the drainage routes

PURPOSE

Lymph node involvement in cancer of the uterine cervix is a major independent prognostic factor for overall survival. The aim of our study was to examine the lymphatic drainage regions of the different parts of the uterine cervix.

METHODS

An anatomical study of fresh cadavers was conducted by injecting patent blue in the anterior or posterior lip of the uterine cervix and dissecting drainage regions. Furthermore, a retrospective radiological and pathological studies were conducted on patients who were treated for early-stage cancer of the uterine cervix with lymph node involvement. Radiological analysis of pre-therapeutic MRIs and/or pathological analysis of surgical specimens showed the precise location of the tumour. A correlation between the anatomy of the primary lesion site and the lymphatic area involved was established.

RESULTS

We administered 15 cadaveric injections: 8 in the anterior lip of the uterine cervix and 7 in the posterior one. For 100% of the anterior lip injections, lymphatic drainage was bilateral ileo-obturator (n = 8/8) combined with bilateral parametrial drainage. For the posterior injections, there was never any ileo-obturator drainage, and 6 of the 7 (75%) posterior injections drained in the posterior uterine serosa. Concerning the clinical study, we included 21 patients. We observed a non-significant tendency towards bilateral lymph node involvement when the tumour of the anterior lip.

CONCLUSION

Physiological lymphatic drainage of the uterine cervix presents anatomical specificities, depending on the structure studied, anterior or posterior lip of the cervix. Better knowledge of these specificities should allow personalized surgery for each patient.

Laparoscopic sentinel lymph node mapping with indocyanine green in endometrial cancer: surgeon's learning curve (cumulative sum analysis)

OBJECTIVES

To evaluate surgeons' learning curves for laparoscopic sentinel lymph node biopsy in endometrial cancer.

METHODS

A prospective observational study was performed at the Oncogynecology Center, Lithuanian University of Health Sciences Hospital, from March 2018 to October 2022. Participating surgeons had no previous experience of laparoscopic sentinel lymph node biopsy with indocyanine green tracer. Cumulative sum analysis was used to create learning curves for the performance of eight surgeons, based on a specific result over a time period. Two different cumulative sum plots were made for each surgeon: successful bilateral sentinel lymph node mapping and removal of sentinel lymph node specimens containing actual lymphatic tissue.

RESULTS

190 patients were included. The overall rate of sentinel lymph node mapping was 89.5%: successful bilateral mapping was achieved in 134 (70.5%) patients, while in 36 (19%) patients sentinel lymph nodes were mapped unilaterally. The bilateral detection rate significantly improved in later study periods (from 59.3% in the first year to 85.0% in the last year; p=0.03). Analysis of the performance of the surgeons for bilateral sentinel lymph node mapping showed that the cumulative sum plot crossed the H₀ limit line after 13 consecutive successful bilateral sentinel lymph node biopsies, indicating an acceptable level of competence to achieve the bilateral detection rate of at least 75%. This was accomplished by only one surgeon after 30 surgeries. Analysis of the performance of the surgeons for identification and removal of specimens containing histologically confirmed lymphatic tissue showed that the cumulative sum plots crossed the H₀ limit line after six consecutive successful sentinel lymph node removals. This was accomplished by most of the surgeons (5 of 8).

CONCLUSION

At least 30 procedures of indocyanine green traced laparoscopic sentinel lymph node biopsy were needed to reach an acceptable level of competence for a bilateral sentinel lymph node detection rate of at least 75%.

TRIAL REGISTRATION NUMBER

ACTRN12619000979156.

Fluorescent Indocyanine Green versus Technetium-99m and Blue Dye for Bilateral SENTinel Lymph Node Detection in Stage I-IIA Cervical Cancer (FluoreSENT): protocol for a non-inferiority study

INTRODUCTION

Nowadays, two predominant methods for detecting sentinel lymph nodes (SLNs) in cervical cancer are in use. The most conventional method is a combination of a radiotracer, technetium-99m (^99mTc) and blue dye. More recently, another method for SLN mapping using indocyanine green (ICG) is becoming widely accepted. ICG is a fluorescent dye, visualised intraoperatively with near-infrared (NIR) fluorescence imaging, providing real-time visual navigation. The presumed advantages of ICG over ^99mTc, that is, being cheaper, non-radioactive and logistically more attractive, are only valuable if its detection rate proves to be at least non-inferior. Before omitting the well-functioning and evidence-based combined approach of ^99mTc and blue dye, we aim to provide prospective evidence on the non-inferiority of ICG with NIR fluorescence imaging.

METHODS AND ANALYSIS

We initiated a prospective non-inferiority study with a paired comparison of both SLN methods in a single sample of 101 patients with International Federation of Gynecology and Obstetrics (FIGO) stage IA-IB2 or IIA1 cervical cancer receiving primary surgical treatment. All patients undergo SLN mapping with ICG and NIR fluorescence imaging in adjunct to mapping with ^99mTc (including single photon emission computed tomography with X-ray computed tomography (SPECT/CT)) and blue dye. Surgeons start SLN detection with ICG while being blinded for the preoperative outcome of SPECT/CT to avoid biased detection with ICG. Primary endpoint of this study is bilateral SLN detection rate of both methods (ie, detection of at least one SLN in each hemipelvis). Since we compare strategies for SLN mapping that are already applied in current daily practice for different types of cancer, no additional risks or burdens are expected from these study procedures.

ETHICS AND DISSEMINATION

The current study is approved by the Medical Ethics Research Committee Utrecht (reference number 21-014). Findings arising from this study will be disseminated in peer-reviewed journals, academic conferences and through patient organisations.

TRIAL REGISTRATION NUMBER

NL9011 and EudraCT 2020-005134-15.

Multiparametric Dual-Time-Point [18F]FDG PET/MRI for Lymph Node Staging in Patients with Untreated FIGO I/II Cervical Carcinoma

[¹⁸F]FDG PET/MRI was shown to have limited sensitivity for N-staging in FIGO I/II cervical carcinoma. Therefore, this prospective study aimed to investigate the additional value of multiparametric dual-time-point PET/MRI and to assess potential influencing factors for lymph node metastasis (LNM) detection. A total of 63 patients underwent whole-body dual-time-point [¹⁸F]FDG PET/MRI 60 + 90 min p.i., and 251 LN were evaluated visually, quantified multiparametrically, and correlated with histology. Grading of the primary tumor (G2/G3) had a significant impact on visual detection (sens: 8.3%/31%). The best single parameter for LNM detection was SUVavg, however, with a significant loss of discriminatory power in G2 vs. G3 tumors (AUC: 0.673/0.901). The independent predictors SUVavg, ∆SUVpeak, LN sphericity, ADC, and histologic grade were included in the logistic-regression-based malignancy score (MS) for multiparametric analysis. Application of MS enhanced AUCs, especially in G2 tumors (AUC: G2:0.769; G3:0.877) and improved the accuracy for single LNM from 34.5% to 55.5% compared with the best univariate parameter SUVavg. Compared with visual analysis, the use of the malignancy score increased the overall sensitivity from 31.0% to 79.3% (Youden optimum) with a moderate decrease in specificity from 98.3% to 75.6%. These findings indicate that multiparametric evaluation of dual-time-point PET/MRI has the potential to improve accuracy compared with visual interpretation and enables sufficient N-staging also in G2 cervical carcinoma.

Sentinel node navigation surgery in cervical cancer: a systematic review and metaanalysis

Sentinel node navigation surgery (SNNS) is used in clinical practice for the treatment of cervical cancer. This study aimed to elucidate the appropriate sentinel lymph node (SLN) mapping method and assess the safety and benefits of SNNS. We searched the PubMed, Ichushi, and Cochrane Library databases for randomized controlled trials (RCT) and studies on SLN in cervical cancer from January 2012 to December 2020. Two authors independently assessed study quality and extracted data. We quantitatively analyzed the detection rate, sensitivity/specificity, and complications and reviewed information, including the survival data of SLN biopsy (SLNB) without pelvic lymphadenectomy (PLND). The detection rate of SLN mapping in the unilateral pelvis was median 95.7% and 100% and in the bilateral pelvis was median 80.4% and 90% for technetium-99 m (Tc) with/without blue dye (Tc w/wo BD) and indocyanine green (ICG) alone, respectively. The sensitivity and specificity of each tracer were high; the area under the curve of each tracer was 0.988 (Tc w/wo BD), 0.931 (BD w/wo Tc), 0.966 (ICG), and 0.977 (carbon nanoparticle). Morbidities including lymphedema, neurological symptoms and blood loss were associated with PLND. One RCT and five studies all showed SNNS without systematic PLND does not impair recurrence or survival in early-stage cervical cancer with a tumor size ≤ 2-4 cm. Both Tc w/wo BD and ICG are appropriate SLN tracers. SNNS can reduce the morbidities associated with PLND without affecting disease progression in early-stage cervical cancer.

Can Conization Specimens Predict Sentinel Lymph Node Status in Early-Stage Cervical Cancer? A SENTICOL Group Study

Simple Summary

Lymph node involvement is one of the major prognosis factors for early-stage cervical cancer. Improvement in preoperative identification of node-positive patients may lead to a more accurate triage to primary chemoradiation for these patients instead of radical surgery followed by adjuvant radiotherapy, given the increased morbidity of combined treatment. Several studies have well established risk factors for node involvement, but they are based on final pathologic examination of radical hysterectomy specimens and are usually extrapolated for preoperative risk assessment. Among these risk factors, tumor size, lymphovascular space invasion (LVSI) and depth of stromal invasion might be assessed in conization specimens. Our findings suggest that patients with depth of stromal invasion lower than 10 mm and no LVSI in conization specimens had lower risk of micro- and macrometastatic SLN. In this subpopulation, full node dissection may be questionable in case of SLN unilateral detection.

Abstract

Background: The prognosis of patients with cervical cancer is significantly worsened in case of lymph node involvement. The goal of this study was to determine whether pathologic features in conization specimens can predict the sentinel lymph node (SLN) status in early-stage cervical cancer. Methods: An ancillary analysis of two prospective multicentric database on SLN biopsy for cervical cancer (SENTICOL I and II) was carried out. Patients with IA to IB2 2018 FIGO stage, who underwent preoperative conization before SLN biopsy were included. Results: Between January 2005 and July 2012, 161 patients from 25 French centers fulfilled the inclusion criteria. Macrometastases, micrometastases and Isolated tumor cells (ITCs) were found in 4 (2.5%), 6 (3.7%) and 5 (3.1%) patients respectively. Compared to negative SLN patients, patients with micrometastatic and macrometastatic SLN were more likely to have lymphovascular space invasion (LVSI) (60% vs. 29.5%, p = 0.04) and deep stromal invasion (DSI) ≥ 10 mm (50% vs. 17.8%, p = 0.04). Among the 93 patients with DSI < 10 mm and absence of LVSI on conization specimens, three patients (3.2%) had ITCs and only one (1.1%) had micrometastases. Conclusions: Patients with DSI < 10 mm and no LVSI in conization specimens had lower risk of micro- and macrometastatic SLN. In this subpopulation, full node dissection may be questionable in case of SLN unilateral detection.

Sentinel lymph node mapping in early-stage cervical cancer: Meta-analysis

BACKGROUND

The value of sentinel lymph node (SLN) mapping for early-stage cervical cancer remains controversial. Therefore, we collected data to investigate the feasibility and diagnostic accuracy of SLN in patients with early-stage (IA-IIA) cervical cancer.

METHODS

We searched Embase, PubMed, and the Cochrane Library databases issued before June 1, 2020. The sample size of the selected study was at least 10 patients with early-stage (IA-IIA) cervical cancer, the pooled detection rates and the separate detection rate (overall detection rate, bilateral detection rate) using blue dye with Tc, technetium 99 (Tc) and indocyanine green (ICG) technique of early-stage cervical cancer was reported. R-3.6.1 software was used to evaluate pooled detection rate and sensitivity.

RESULTS

Two thousand one hundred sixty-four patients included for analysis in 28 studies ranging from 12 to 405 patients. The combined overall detection rate of SLN mapping was 95% with a 72% pooled bilateral detection rate. The sensitivity of the combined overall detection rate of SLN mapping was 94.99% as well as a sensitivity of 72.43% bilateral detection rate. The overall detection rate of SLN was 96% for blue dye with Tc, 95% for Tc, 98% for ICG technique. The bilateral detection rate of SLN was 76% for blue dye with Tc, 63% for Tc, 85% for ICG technique. The sensitivity of the overall detection rate of SLN mapping was 97.76% as well as a sensitivity of 84.96% bilateral detection rate of ICG technique.

CONCLUSION

In early-stage cervical cancer, overall detection rate of SLN mapping is elevated while bilateral detection rate is lower. The overall detection rate (98%) as well as bilateral rate (85%) of ICG seems to be a better SLN mapping technique among the method of SLN mapping (using blue dye with Tc, Tc or ICG). We believe SLN mapping may be considered contemporary technique which could provide additional benefits over traditional pelvic lymphadenectomy. While promising results in SLN mapping has been found, larger patient samples, including randomized studies, are required at the same time.

Failure of scintigraphy lymphatic mapping in endometrial cancer. Causes and solutions

AIM

To evaluate the effect of technical problems and patient characteristics on sentinel lymph node (SLN) scintigraphic detection and mapping success in early stages of endometrial cancer (EC).

METHODS

Patients with clinical early stage EC (IA-IB) underwent SLN mapping using technetium-99m-nanocolloid,between September 2011 and February 2020. were included. There were excluded cases with technical problems, 92 patients were included for the analysis of the diagnostic performance and the relation of mapping failure (pelvic unilateral or not detected SLN) with patient (age, body mass index, previous pelvic disease or surgery) and disease characteristics (histology, grade, myometrial invasion, lymphovascular space infiltration, tumor size, and lymphatic infiltration risk).

RESULTS

The overall detection rate was 79%. Lymph node metastases were diagnosed in 7 patients. Age (p=0.01), depth of myometrial invasion ≥ 50% (p=0.04) and high risk of lymphatic infiltration (p=0.02) were positively associated with mapping failure. In multivariate analysis, age was significantly associated with mapping failure [odds ratio=1.63, 95%CI: 1.06-2.50; p=0.027].

CONCLUSIONS

Age, depth of myometrial invasion and high risk of lymphatic infiltration were the factors associated with higher mapping failure. An individualized injection technique, optimizing the methodology, could minimize the detection failures.

Lymph Node Staging with a Combined Protocol of 18F-FDG PET/MRI and Sentinel Node SPECT/CT: A Prospective Study in Patients with FIGO I/II Cervical Carcinoma

Lymph node metastasis (LNM) is present in a minority of patients with early stages of cervical carcinomas. As conventional imaging including PET/CT has shown limited sensitivity, systematic lymphadenectomies are often conducted for staging purposes. Therefore, the aim of this prospective study was to analyze the impact of 18F-FDG PET/MRI in addition to sentinel lymph node (SLN) biopsy on lymph node (LN) status. Methods: Forty-two women with an initial diagnosis of Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) IA-IIB cervical carcinoma were included between March 2016 and April 2019. Each patient underwent preoperative whole-body 18F-FDG PET/MRI and SLN imaging with SPECT/CT after intracervical injection of 99mTc-labeled nanocolloid. Systematic lymphadenectomy and SLN biopsy served as the reference standard. Staging using PET/MRI was performed by nuclear medicine and radiology experts working in consensus. Results: One patient was excluded from surgical staging because of liver metastases newly diagnosed on PET/MRI. The overall prevalence of LNM in the remaining 41 patients was 29.3% (12/41). Five of 12 patients with LNM had solely small metastases with a maximum diameter of 5 mm. The consensus interpretation showed PET/MRI to have a specificity of 100% (29/29; 95% CI, 88.3%-100%) for LNM staging but a low sensitivity, 33.3% (4/12; 95% CI, 12.8%-60.9%). LN size was the most important factor for the detectability of metastases, since only LNMs larger than 5 mm could be identified by PET/MRI (sensitivity, 57.1% for >5 mm and 0% for ≤5 mm). Paraaortic LNM was evaluated accurately in 3 of the 4 patients with paraaortic LN metastasis. SLNs were detectable by SPECT/CT in 82.9% of the patients or 69.0% of the hemipelves. In cases with an undetectable SLN on SPECT/CT, the malignancy rate was considerably higher (31.2% vs. 19.3%). The combination of PET/MRI and SLN SPECT/CT improved the detection of pelvic LNM from 33.3% to 75%. Conclusion:18F-FDG PET/MRI is a highly specific N-staging method and improves LNM detection. Because of the limited sensitivity in frequently occurring small LNMs, PET/MRI should be combined with SLN mapping. The proposed combined protocol helps to decide whether extensive surgical staging is necessary in patients with FIGO I/II cervical cancer.

Sentinel lymph node mapping in early-stage cervical cancer - A national prospective multicenter study (SENTIREC trial)

OBJECTIVES

Sentinel lymph node (SLN) mapping may replace staging radical pelvic lymphadenectomy in women with early-stage cervical cancer. In a national multicenter setting, we evaluated SLN mapping in women with early-stage cervical cancer and investigated the accuracy of SLN mapping and FDG-PET/CT in tumors >20 mm.

METHODS

We prospectively included women with early-stage cervical cancer from March 2017-January 2021 to undergo SLN mapping. Women with tumors >20 mm underwent completion pelvic lymphadenectomy and removal of FDG-PET/CT positive nodes. We determined SLN detection rates, incidence of nodal disease, sensitivity and negative predictive value (NPV) of SLN mapping, and the sensitivity, specificity, NPV, and positive predictive value (PPV) of FDG-PET/CT.

RESULTS

We included 245 women, and 38 (15.5%) had nodal metastasis. The SLN detection rate was 96.3% (236/245), with 82.0% (201/245) bilateral detection. In a stratified analysis of 103 women with tumors >20 mm, 27 (26.2%) had nodal metastases. The sensitivity of SLN mapping adhering to the algorithm was 96.3% (95% CI 81.0-99.9%) and the NPV 98.7% (95% CI 93.0-100%). For FDG-PET/CT imaging the sensitivity was 14.8% (95% CI 4.2-33.7%), the specificity 85.5% (95% CI 75.6-92.5%), the NPV 73.9% (95% CI 63.4-82.7%), and the PPV 26.7% (95% CI 7.8-55.1%).

CONCLUSIONS

SLN mapping seems to be an adequate staging procedure in early-stage cervical cancer tumors ≤20 mm. In tumors >20 mm, SLN mapping is highly sensitive but demands full adherence to the SLN algorithm. We recommend completion pelvic lymphadenectomy in tumors >20 mm until the oncological safety is established. FDG-PET/CT for nodal staging of women with early-stage cervical cancer seems limited.

Indocyanine green versus technetium-99m with blue dye for sentinel lymph node detection in early-stage cervical cancer: A systematic review and meta-analysis

Background

The fluorescent dye indocyanine green (ICG) has emerged as a promising tracer for intraoperative detection of sentinel lymph nodes (SLNs) in early‐stage cervical cancer. Although researchers suggest the SLN detection of ICG is equal to the more conventional combined approach of a radiotracer and blue dye, no consensus has been reached.

Aims

We aimed to assess the differences in overall and bilateral SLN detection rates with ICG versus the combined approach, the radiotracer technetium‐99m (^99mTc) with blue dye.

Methods and Results

We searched MEDLINE, Embase, and the Cochrane Library from inception to January 1, 2020 and included studies reporting on a comparison of SLN detection with ICG versus ^99mTc with blue dye in early‐stage cervical cancer. The overall and bilateral detection rates were pooled with random‐effects meta‐analyses.

From 118 studies retrieved seven studies (one cross‐sectional; six retrospective cohorts) were included, encompassing 589 patients. No significant differences were found in the pooled overall SLN detection rate of ICG versus ^99mTc with blue dye. Meta‐analyses of all studies showed ICG to result in a higher bilateral SLN detection rate than ^99mTc with blue dye; 90.3% (95%CI, 79.8‐100.0%) with ICG versus 73.5% (95%CI, 66.4‐80.6%) with 99mTc with blue dye. This resulted in a significant and clinically relevant risk difference of 16.6% (95%CI, 5.3‐28.0%). With sensitivity analysis, the risk difference of the bilateral detection rate maintained in favor of ICG but was no longer significant (13.2%, 95%CI −0.8‐27.3%).

Conclusion

ICG appears to provide higher bilateral SLN detection rates compared to ^99mTc with blue dye in patients with early‐stage cervical cancer. However, in adherence with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines, the quality of evidence is too low to provide strong recommendations and directly omit the combined approach of ^99mTc with blue dye.

Region-specific Risk Factors for Pelvic Lymph Node Metastasis in Patients with Stage IB1 Cervical Cancer

Objectives: We aimed to identify the risk factors associated with pelvic lymph node metastasis (LNM) at each anatomic location in patients with stage IB1 cervical cancer.

Methods: A primary cohort of 728 patients with stage IB1 cervical cancer who underwent radical hysterectomy and systematic pelvic lymphadenectomy were retrospectively studied. All removed pelvic nodes (N=20,134) were pathologically examined. The risk factors for LNM in different anatomic regions (obturator, internal iliac, external iliac, and common iliac) were evaluated by multivariate logistic regression analyses. Nomograms were generated from the primary cohort and validated in another external cohort (N=242). The performance of the nomogram was assessed by its calibration and discrimination. Overall survival and progression-free survival in patients with different LNM patterns were compared.

Results: LNM was found in 266 (1.3%) removed nodes and 106 (14.6%) patients. The incidences of LNM at the obturator, internal iliac, external iliac, common iliac, and parametrial regions were 8.5%, 5.4%, 4.7%, 1.9% and 1.8%, respectively. Among others, tumour size and lymph-vascular space invasion (LVSI), which are preoperatively assessable, were identified as independent risk factors of LNM in the common iliac region and the lower pelvis, respectively, and age was an additional independent risk factor of obturator LNM. The negative predictive values of tumour size <2 cm for common iliac LNM and negative LVSI combined with older age (> 50 years) for obturator LNM were 100% and 98.7%, respectively. A nomogram of these two factors showed good calibration and discrimination (concordance index, 0.761 in the primary cohort and 0.830 in validation cohort). The patients with common iliac LNM had poorer survival than those with LNM confined to the lower pelvis, while the differences in survival between patients with LNM confined to one node, one region or single side and those with more widely spreading LNM were not statistically significant.

Conclusions: Tumour size, LVSI and age are region-specific risk factors for pelvic LNM in IB1 cervical cancer, which could be used to allocate the appropriate extent of pelvic lymphadenectomy.

Comparison of SPECT-CT with intraoperative mapping in cervical and uterine malignancies

INTRODUCTION

The objective was to evaluate whether hybrid imaging combining single photon emission tomography with computed tomography (SPECT/CT) provides additional clinical value for dectection of sentinel lymph nodes (SLNs) compared with intraoperative combined mapping in uterine and cervical malignancies.

METHODS

This was a retrospective study of prospectively collected data from patients with stages IA-IB2 cervical cancer (International Federation of Gynecology and Obstetrics (FIGO) 2018) or stage I endometrial cancer, who underwent preoperative SPECT/CT for SLN detection. All included patients had dual injection of technetium-99m (^99mTc) with patent blue or indocyanine green.

RESULTS

A total of 171 patients were included with 468 SLNs detected during surgery: 146/171 patients (85.4%) had both radiotracer and blue injection whereas 25/171 patients (14.6%) had radiotracer and indocyanine green injected. The overall detection rate was 95.3%. The detection rate of SLN mapping was 74.9% for SPECT/CT, 90.6% for ^99mTc, 91.8% for blue dye, and 100% for indocyanine green. Bilateral drainage was found in 140 patients (81.9%), detected by ^99mTc in 105 patients (61.4%), by blue in 99 patients (67.3%), by indocyanine green in 23 patients (92%), and by SPECT/CT in 62 patients (36.4%). Atypical SLN locations were identified by SPECT/CT in 64 patients (37.4%), by 99mTc in 28 patients (16.4%), by blue in 17 patients (9.9%), and by indocyanine green in 8 patients (4.7%). Sensitivity and negative predictive value of SLN biopsy to detect lymph node metastasis using dual injection of different intraoperative combined techniques were 88.9% and 97.5%, respectively.

CONCLUSION

SPECT/CT enhanced topographic delineation of SLN and more accurately identified drainage to atypical locations. Fluorescent SLN mapping using indocyanine green offered the highest SLN detection rate. When indocyanine green was used, SPECT/CT did not increase SLN detection, and did not add further information to improve lymph node localization and removal.

Controversies in Sentinel Lymph Node Biopsy for Gynecologic Malignancies

OBJECTIVE

Sentinel lymph node (SLN) biopsy represents an evolution in the advancement of minimally invasive surgical techniques for gynecologic cancers. Prospective and retrospective studies have consistently shown its accuracy in the detection of lymph node metastases for endometrial and cervical cancers. However, consistent with any emerging surgical technique in the early phases of adoption, new questions have arisen regarding its application and impact. This paper served as a scoping review to identify the key controversies that have arisen in the field of SLN biopsy for endometrial and cervical cancers.

DATA SOURCES

Several key controversies were identified, and PubMed, the Cochrane Library (cochranelibrary.com) advanced search function, and the National Comprehensive Cancer Network guidelines were searched for supporting evidence. These included search terms such as "the accuracy of SLN biopsy for high grade endometrial cancer or cervical cancers >2-cm," "cost effectiveness of SLN biopsy for gynecologic cancers," "clinical significance of low volume metastases in endometrial cancer," "morbidity of SLN biopsy for endometrial and cervical cancer," and "impact on cancer survival of SLN biopsy for endometrial and cervical cancer."

METHODS OF STUDY SELECTION

Studies were selected for review if they included significant numbers of patients, were level I evidence, or were prospective trials. Where this level of evidence failed to exist, seminal observational series that were published in high-quality journals were included.

TABULATION, INTEGRATION, AND RESULTS

Similar studies were listed and subcategorized and cross-compared, excluding those that included repeated analyses of the same patient populations. The relevant clinical trials or observational studies were clustered and reviewed for each chosen controversy. Adequate evidence supports the accuracy of SLN biopsy in the staging of high-grade endometrial cancer and cervical cancer, and it seems to be a cost-effective strategy for invasive endometrial cancer. Conclusive evidence was lacking with respect to the oncologic outcomes related to SLN biopsy, the impact on patient morbidity, and whether clinicians should treat isolated tumor cells in SLNs with adjuvant therapy.

CONCLUSION

SLN biopsy is an accepted staging strategy for cervical and endometrial cancer surgery; however, controversies remain in how it can be applied with the most safety and efficacy. These ultimately need to be resolved with further clinical trials and observations of larger series of patients.

Status of Sentinel Lymph Node Biopsy in Vulvar and Cervical Cancer

Assessment of lymphatic metastasis is an essential component of solid tumour staging. Sentinel lymph node (SLN) biopsy is a minimally invasive procedure that allows regional lymph node involvement by tumour to be estimated by selectively examining the sentinel lymph node while minimising the morbidity of systematic lymph node dissection. Within the group of genital cancers, the diagnostic value of SLN biopsy is rated differently. For selected patients with early-stage vulvar cancer (unifocal primary tumour < 4 cm, clinically negative inguinal lymph nodes) the SLN technique is already an established procedure in the guidelines of the German Society for Gynaecology and Obstetrics (DGGG)/German Cancer Society (DKG) and the recommendations of the European Society of Gynaecological Oncology (ESGO). For cervical cancer, SLN biopsy has not yet been sufficiently standardised but can be considered for patients without risk factors with a primary tumour size < 2 cm. The SLN is identified by combined use of radioactive ^99m technetium nanocolloid and patent blue. The use of indocyanine green offers an alternative for SLN identification with few side effects. Recent studies aim to increase the diagnostic reliability of intraoperative frozen section analysis as this continues to show limited sensitivity in both vulvar and cervical cancer. The rate of detection of micrometastases can be increased by additional ultrastaging, the prognostic significance of which for both diseases is still unclear. The prognostic value of SLN biopsy compared with systematic lymph node dissection is being investigated in current studies (GROINSS-V-II for vulvar cancer and SENTIX-, SENTICOL-3 for cervical cancer). For this review article, a guideline-based literature search was performed in the National Library of Medicine (PubMed/MEDLINE) database with a particular focus on recent cohort studies and conference contributions.

The impact of low-volume metastasis on disease-free survival of women with early-stage cervical cancer

PURPOSE

We aimed to assess the impact of low-volume metastasis (micrometastasis and isolated tumor cells) on disease-free survival (DFS) of women with early-stage cervical cancer.

METHODS

Women with clinically suspected stage 1A-IB2 (FIGO 2018 classification) disease who underwent retroperitoneal nodal staging between October 2010 and April 2018, were retrospectively analyzed. The group of women who had undergone lymphadenectomy and standard node pathologic analysis (H&E group), were compared to the group undergoing sentinel node mapping (SLN) and ultrastaging with or without lymphadenectomy (ultrastaging group). At a median follow-up of 45 months, the DFS curves were analyzed.

RESULTS

Overall, 573 patients were revised (272 in the H&E group and 302 in the ultrastaging group). Eighty-five patients presented lymph node metastasis (32 in H&E, 53 in ultrastaging). Ultrastaging protocol increased the rate of low-volume metastasis by 5.6%. Twenty patients showed exclusive micrometastasis or ITC's. Seventy-three recurrences occurred (35 in H&E, 38 in ultrastaging). Only 1 out of 53 patients in the ultrastaging group (1.9%) presented with micrometastasis recurred. The 3-year disease-free survival was 89% for the H&E group, and 88% for the ultrastaging group, respectively (p = 0.175).

CONCLUSION

Ultrastaging analysis allowed increasing the detection of low volume metastasis in women with early-stage cervical cancer. However, the type of nodal staging did not have an impact on patients' 3-year disease-free survival.

Sentinel lymph node mapping and intraoperative assessment in a prospective, international, multicentre, observational trial of patients with cervical cancer: The SENTIX trial

BACKGROUND

SENTIX (ENGOT-CX2/CEEGOG-CX1) is an international, multicentre, prospective observational trial evaluating sentinel lymph node (SLN) biopsy without pelvic lymph node dissection in patients with early-stage cervical cancer. We report the final preplanned analysis of the secondary end-points: SLN mapping and outcomes of intraoperative SLN pathology.

METHODS

Forty-seven sites (18 countries) with experience of SLN biopsy participated in SENTIX. We preregistered patients with stage IA1/lymphovascular space invasion-positive to IB2 (4 cm or smaller or 2 cm or smaller for fertility-sparing treatment) cervical cancer without suspicious lymph nodes on imaging before surgery. SLN frozen section assessment and pathological ultrastaging were mandatory. Patients were registered postoperatively if SLN were bilaterally detected in the pelvis, and frozen sections were negative.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02494063).

RESULTS

We analysed data for 395 preregistered patients. Bilateral detection was achieved in 91% (355/395), and it was unaffected by tumour size, tumour stage or body mass index, but it was lower in older patients, in patients who underwent open surgery, and in sites with fewer cases. No SLN were found outside the seven anatomical pelvic regions. Most SLN and positive SLN were localised below the common iliac artery bifurcation. Single positive SLN above the iliac bifurcation were found in 2% of cases. Frozen sections failed to detect 54% of positive lymph nodes (pN1), including 28% of cases with macrometastases and 90% with micrometastases.

INTERPRETATION

SLN biopsy can achieve high bilateral SLN detection in patients with tumours of 4 cm or smaller. At experienced centres, all SLN were found in the pelvis, and most were located below the iliac vessel bifurcation. SLN frozen section assessment is an unreliable tool for intraoperative triage because it only detects about half of N1 cases.