Clinical application of the sentinel lymph node technique in early ovarian cancer: a pilot study

Sentinel Node Mapping in Ovarian Tumors: A Study Using Lymphoscintigraphy and SPECT/CT

Purpose

Ovarian cancer in the early stage requires a complete surgical staging, including radical lymphadenectomy, implying subsequent risk of morbidity and complications. Sentinel lymph node (SLN) mapping is a procedure that attempts to reduce radical lymphadenectomy-related complications and morbidities. Our study evaluates the feasibility of SLN mapping in patients with ovarian tumors by the use of intraoperative Technetium-99m-Phytate (Tc-99m-Phytate) and postoperative lymphoscintigraphy using tomographic (single-photon emission computed tomography/computed tomography (SPECT/CT)) acquisition.

Materials and Methods

Thirty-two patients with ovarian mass participated in this study. Intraoperative injection of the radiopharmaceutical was performed just after laparotomy and before the removal of tumor in utero-ovarian and suspensory ligaments of the ovary just beneath the peritoneum. Subsequently, pelvic and para-aortic lymphadenectomy was performed for malignant masses, and the presence of tumor in the lymph nodes was assessed through histopathological examination. Conversely, lymphadenectomy was not performed in patients with benign lesions or borderline ovarian tumors. Lymphoscintigraphy was performed within 24 hr using tomographic acquisition (SPECT/CT) of the abdomen and pelvis.

Results

Final pathological examination showed 19 patients with benign pathology, 5 with borderline tumors, and 6 with malignant ovarian tumors. SPECT/CT identified SLNs in para-aortic-only areas in 6 (20%), pelvic/para-aortic areas in 14 (47%), and pelvic-only areas in 7 (23%) cases. Notably, additional unusual SLN locations were revealed in perirenal, intergluteal, and posterior to psoas muscle regions in three patients. We were not able to calculate the false negative rate due to the absence of patients with involved lymph nodes.

Conclusion

SLN mapping using intraoperative injection of radiotracers is safe and feasible. Larger studies with more malignant cases are needed to better evaluate the sensitivity of this method for lymphatic staging of ovarian malignancies.

Molecular image-guided surgery in gynaecological cancer: where do we stand?

PURPOSE

The aim of this review is to give an overview of the current status of molecular image-guided surgery in gynaecological malignancies, from both clinical and technological points of view.

METHODS

A narrative approach was taken to describe the relevant literature, focusing on clinical applications of molecular image-guided surgery in gynaecology, preoperative imaging as surgical roadmap, and intraoperative devices.

RESULTS

The most common clinical application in gynaecology is sentinel node biopsy (SNB). Other promising approaches are receptor-target modalities and occult lesion localisation. Preoperative SPECT/CT and PET/CT permit a roadmap for adequate surgical planning. Intraoperative detection modalities span from 1D probes to 2D portable cameras and 3D freehand imaging.

CONCLUSION

After successful application of radio-guided SNB and SPECT, innovation is leaning towards hybrid modalities, such as hybrid tracer and fusion of imaging approaches including SPECT/CT and PET/CT. Robotic surgery, as well as augmented reality and virtual reality techniques, is leading to application of these innovative technologies to the clinical setting, guiding surgeons towards a precise, personalised, and minimally invasive approach.

Mapping sentinel lymph nodes in early-stage ovarian cancer (MELISA) trial - a further step towards lymphadenectomy replacement

OBJECTIVE

Sistematic pelvic and para-aortic lymphadenectomy is part of the staging surgery for early-stage epithelial ovarian cancer, with no therapeutic value. The Mapping Sentinel Lymph Nodes In Early-Stage Ovarian Cancer (MELISA) trial prospectively assessed the SLN detection rate and the diagnostic accuracy of the SLN mapping technique in patients with early-stage epithelial ovarian cancer.

METHODS

This prospective, single-arm study included patients diagnosed with early-stage epithelial ovarian cancer (FIGO stages I and II), via either primary surgery or re-staging surgery. SLN mapping was performed by injecting 0.2 mL of 37-mBq 99mTc-nanocoloid albumin and 2 mL of 2.5 mg/mL indocyanine green into the infundibulopelvic and utero-ovarian ligaments. After removal of SLNs, a complete systematic pelvic and para-aortic lymphadenectomy was performed. SLN Ultrastaging analysis was applied. The primary outcome was the overall SLN detection rate, either with one or both tracers. Secondary outcomes were the diagnostic accuracy of detecting lymph node metastases and factors that may influence SLN detection.

RESULTS

Thirty patients were included. SLNs were identified in 27 patients (90%). Detection rates in primary and re-staging surgery were 89% and 92%, respectively. Para-aortic drainage was the predominant lymphatic spread, observed in 26 of 27 patients. Ultrastaging pathologic reports listed 1 SLN with macrometastasis, 1 with micrometastasis, and 5 with isolated tumor cells; the sensitivity of SLN mapping was 100%, with a false-negative rate of 0%. Univariate analysis showed a nonsignificant higher proportion of patients with uterine fibroids, adenomyosis, and endometriosis (100%, 67%, 67%, respectively) in patients in whom SLNs were not detected.

CONCLUSION

SLN mapping has a high detection rate (90%) and is an accurate technique for detecting lymph node involvement in early-stage epithelial ovarian cancer. SLN mapping is a potential alternative to systematic lymphadenectomy to reduce associated morbidity, but further research is needed to evaluate the impact of SLN mapping on oncologic outcomes and its cost-effectiveness.

Robotic-assisted para-aortic lymphadenectomy: Technique and indications in gynecological oncology

The benefits of minimally-invasive surgeries have been documented, and they have been established as the preferred approach for gynecological surgeries. With the development of robotic surgery, many highly complex surgeries can benefit from these advantages. Due to the complexity of aortocaval lymphadenectomy, surgical technique protocols have been described to reduce risks by maximizing benefits. We describe the technique using five ports (4 robotic arms and an assistant) to work the upper abdominal field, and different instruments recommended in each of their positions to reduce errors and optimize surgical time. After the "step by step" description, we summarize indications of aortocaval lymphadenectomy for every gynecological cancer in different stages.

Clinical relevance of sentinel lymph node biopsy in early ovarian cancer

The first-line treatment for early ovarian cancer typically involves primary debulking surgery aimed at maximal cytoreduction, alongside adjuvant chemotherapy if clinically indicated. Nodal assessment involving pelvic and para-aortic lymph node dissection is typically performed during the primary debulking surgery. However, the survival benefit of lymphadenectomy in patients with early ovarian cancer has not been well established, and the procedure is associated with longer operation time and higher perioperative complications. With the emergence of minimally invasive surgery as a potential alternative to laparotomy for early ovarian cancer, sentinel lymph node biopsy has been evaluated in this setting. In this review, we summarized the current literature regarding sentinel lymph node biopsy in patients with early ovarian cancer, focusing on the clinical relevance of this method, including its detection rate and diagnostic accuracy. Additionally, we discuss the current status of clinical trials investigating sentinel lymph node biopsy in early ovarian cancer cases.

Feasibility of Sentinel Lymph Node Biopsy in Early-Stage Epithelial Ovarian Cancer: A Systematic Review and Meta-Analysis

Sentinel lymph node biopsy (SLNB) has been widely adopted in the management of early-stage gynaecological cancers such as endometrial, vulvar and cervical cancer. Comprehensive surgical staging is crucial for patients with early-stage ovarian cancer and currently, that includes bilateral pelvic and para-aortic lymph node assessment. SLNB allows the identification, excision and pathological assessment of the first draining lymph nodes, thus negating the need for a full lymphadenectomy. We systematically searched the MEDLINE, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) databases (from inception to 3 November 2022) in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Our search identified 153 articles from which 11 were eligible for inclusion. Patients with clinical stage I-II ovarian cancer undergoing sentinel lymph node biopsy were included. Statistical analysis was performed in RStudio using the meta package, where meta-analysis was performed for the detection. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies C (QUADAS-C) tool. Overall, 11 observational studies met the predetermined criteria and these included 194 women. The meta-analysis showed that the detection rate of sentinel lymph nodes in early-stage ovarian cancer was 94% (95% CI of 86% to 1.00%). Significant heterogeneity was noted among the studies with Q = 47.6, p < 0.0001, I2 = 79% and τ2 = 0.02. Sentinel lymph nodes in early-stage ovarian cancer have a high detection rate and can potentially have applicability in clinical practice. However, considering the small number of participants in the studies, the heterogeneity among them and the low quality of evidence, the results should be interpreted with caution. Larger trials are needed before a change in clinical practice is recommended.

Sentinel lymph node detection in early-stage ovarian cancer: a systematic review and meta-analysis

BACKGROUND

A systematic pelvic and para-aortic lymphadenectomy remains the surgical standard management of early-stage epithelial ovarian cancer. Sentinel lymph node mapping is being investigated as an alternative procedure; however, data reporting sentinel lymph node performance are heterogeneous and limited.

OBJECTIVE

This study aimed to evaluate the detection rate and diagnostic accuracy of sentinel lymph node mapping in patients with early-stage ovarian cancer.

METHODS

A systematic search was conducted in Medline (through PubMed), Embase, Scopus, and the Cochrane Library. We included patients with clinical stage I-II ovarian cancer undergoing a sentinel lymph node biopsy and a pelvic and para-aortic lymphadenectomy as a reference standard. We conducted a meta-analysis for the detection rates and measures of diagnostic accuracy and assessed the risk of bias using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) with identifying number CRD42022351497.

RESULTS

After duplicate removal, we identified 540 studies, 18 were assessed for eligibility, and nine studies including 113 patients were analyzed. The pooled detection rates were 93.3% per patient (95% CI 77.8% to 100%; I2=74.3%, p<0.0001), and the sentinel lymph node technique correctly identified 11 of 12 patients with lymph node metastases, with a negative predictive value per patient of 100% (95% CI 97.6% to 100%; I2=0%). The combination of indocyanine green and 99mTc-albumin nanocolloid had the best detection rate (100% (95% CI 94% to 100%; I2=0%)) when injected into the utero-ovarian and infundibulo-pelvic ligaments.

CONCLUSION

Sentinel lymph node biopsy in early-stage ovarian cancer showed a high detection rate and negative predictive value. The utero-ovarian and infundibulo-pelvic injection using the indocyanine green and technetium-99 combination could increase sentinel lymph node detection rates. However, given the limited quality of evidence and the small number of reports, results from ongoing trials are awaited before its implementation in routine clinical practice.

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.

Utilization of sentinel lymph node biopsy in the early ovarian cancer surgery

OBJECTIVE

Sentinel lymph node (SLN) biopsy has been incorporated into surgical care for many malignancies; however, the utility has not been examined in ovarian cancer. This study examined population-level trends, characteristics, and outcomes related to SLN biopsy in early stage ovarian cancer.

METHODS

This is a retrospective cohort study querying the National Cancer Institute's Surveillance, Epidemiology, and End Result Program from 2003-2018. The study population consisted of 11,512 women with stage I ovarian cancer who had adnexectomy-based surgical staging including lymph node evaluation. Exposure allocation was based on SLN biopsy use. Main outcomes measured were (i) trends and characteristics associated with SLN biopsy use, assessed by multivariable logistic regression model, and (ii) overall survival assessed with inverse provability of treatment weighting propensity score.

RESULTS

SLN biopsy was performed in less than 1% of study population. In a multivariable analysis, recent surgery (2011-2018 versus 2003-2010, odds ratio [OR] 1.64, 95% confidence interval [CI] 1.03-2.59), smaller tumor size (< 10 versus ≥ 10 cm, OR 3.07, 95% CI 1.20-7.84), and East registry area (OR 2.74, 95% CI 1.73-4.36) remained independent characteristics for SLN biopsy use. In a propensity score weighted model, 5-year overall survival rate was 90.5% for the SLN biopsy-incorporated group and 88.6% for the lymphadenectomy group (hazard ratio 0.96, 95% CI 0.53-1.73).

CONCLUSION

SLN biopsy was rarely performed for early ovarian cancer surgery during the study period with insufficient evidence to interpret the survival effect. SLN biopsy in early ovarian cancer appears to be in early development phase, warranting further study and careful evaluation to assess feasibility and oncologic outcome.

Can fluorescence-guided surgery improve optimal surgical treatment for ovarian cancer? A systematic scoping review of clinical studies

BACKGROUND

The predicament of achieving optimal surgical intervention faced by surgeons in treating ovarian cancer has driven research into improving intra-operative detection of cancer using fluorescent materials.

OBJECTIVE

To provide a literature overview on the clinical use of intra-operative fluorescence-guided surgery for ovarian cancer, either for cytoreductive surgery or sentinel lymph node (SLN) biopsy.

METHODS

The systematic review included studies from June 2002 until October 2021 from PubMed, Web of Science, and Scopus as well as those from a search of related literature. Studies were included if they investigated the use of fluorescence-guided surgery in patients with a diagnosis of ovarian cancer. Authors charted variables related to study characteristics, patient demographics, baseline clinical characteristics, fluorescence-guided surgery material, and treatment details, and surgical, oncological, and survival outcome variables. After screening 2817 potential studies, 24 studies were included.

RESULTS

Studies investigating the role of fluorescence-guided surgery to visualize tumor deposits or SLN biopsy included the data of 410 and 118 patients, respectively. Six studies used indocyanine green tracer with a mean SLN detection rate of 92.3% with a pelvic and para-aortic detection rate of 94.8% and 96.7%, respectively. The sensitivity, specificity, and positive predictive value for micrometastases detection of OTL38 and 5-aminolevulinc acid at time of cytoreduction were 92.2% vs 79.8%, 67.3% vs 94.8%, and 55.8% vs 95.8%, respectively.

CONCLUSION

Fluorescence -guided surgery is a technique that may improve the detection rate of micrometastases and SLN identification in ovarian cancer. Further research is needed to establish whether this will lead to improved patient outcomes.

Where are we going with sentinel nodes mapping in ovarian cancer?

Lymph node involvement is a major predictive indicator in early-stage epithelial ovarian cancer (EOC). There is presently no effective way to determine lymph node involvement other than surgical staging. As a result, traditional ovarian cancer surgery still includes pelvic and paraaortic lymphadenectomy. However, it might be linked to higher blood loss, lengthier operations, and longer hospital stays. The creation of a technique for accurately predicting nodal status without significant lymphadenectomy is thus the subject of ongoing research. Sentinel lymph nodes (SLN) mapping is a routine procedure in oncological surgery and has been proven to be effective and safe in cervical, vulvar, and uterine cancer. On the other hand, SLN mapping is not yet widely accepted and recognized in EOC. A thorough search of the literature was conducted between January 1995 to March 2022, using PubMed and Embase. This review included studies on lymphatic outflow of the ovaries and the sentinel lymph node method. A total of 13 studies involving 212 patients who underwent sentinel lymph node mapping for ovaries were included. Both open and laparoscopic approach are used. The most popular injection site is the ovarian ligaments, and a variety of agents are utilized, although the main markers were, technetium-99m radiocolloid (Tc-99m) or indocyanine green, either alone or in combination. Overall detection rate for SLN in ovaries is 84.5% (interquartile range: 27-100%). We suggest a standardized method for sentinel lymph node mapping in ovarian cancer. The detection rates, characterization and true positive rates of the approach in investigations support further study. The use of ultra-staging is essential for lower-volume metastasis and reproducibility. To ascertain the clinical utility of sentinel node in early ovarian cancer, larger collaborative prospective clinical trials are necessary.

Axillary lymph‐node metastases as the primary presentation of high‐grade serous ovarian carcinoma: A case report

We reported a female presented with an initial diagnosis of metastatic axillary lymph‐node carcinoma that comprehensive assessments revealed a definitive diagnosis of high‐grade serous ovarian carcinoma as the primary tumor.

Sentinel lymph node identification in early stage ovarian cancer: is it still possible after prior tumor resection?

Objective

Sentinel lymph node (SLN) detection in ovarian cancer is feasible when tracers are injected before the pathological ovary is resected. This study aims to investigate whether the SLN identification is also feasible in patients whose ovarian tumor has already been resected with injection of the tracer into the ovarian ligaments stumps, i.e. in the event that a frozen section confirms malignancy.

Methods

Patients who underwent laparotomy with frozen section confirming an ovarian malignancy, and those who underwent a second staging laparotomy after prior resection of a malignant ovarian mass, were included. Blue dye and a radioactive isotope were injected in the stumps of the ligamentum ovarium proprium and the ligamentum infundibulo-pelvicum. After an interval of at least 15-min, the sentinel node(s) were identified using either the gamma-probe and / or blue dye.

Results

A total of 11 patients were included in the study, the sentinel node (SLN) procedure was completed in all 11 patients. At least one SLN was identified in 3 patients, resulting in a rather low detection rate of 27,3%.

Conclusion

In this study we showed that SLN procedure after (previous) resection of the tumor seems inferior to detect sentinel nodes when compared to injection of the tracer in the ovarian ligaments before tumor resection.

Trial registration

NCT02540551

[Sentinel lymph node biopsy in the management of early-stage ovarian cancer: A systematic review of the literature]

The initial management of early-stage ovarian cancer consists of staging surgery including pelvic and para-aortic lymphadenectomy. The use of the sentinel lymph node (SLN) procedure in this setting may decrease the morbidity associated with this surgery. The objective of this review was to evaluate the feasibility of the SLN procedure in ovarian cancer diagnosed at an early stage by comparing the different techniques used and their accuracy. A systematic literature search was performed on PubMed and ClinicalTrials.gov for articles in English or French about the SLN technique in ovarian cancer. Ten studies were included in the analysis, with a total of 179 patients. The main tracers used were Technetium-99m, indocyanine green, and patent blue, and the most common site of injection was the proper ovarian and unfundibulopelvic ligaments. The overall detection rate was 87.7%. Of the small number of cases of lymph node metastasis reported, the SLN procedure had a sensitivity of 90.9% and a negative predictive value of 98.8%. The sentinel node procedure appears to be feasible and safe and could be reliable in determining the lymph node status of patients with early-stage ovarian cancer.

Sentinel Lymph Nodes and Precision Surgery in Gynecologic Cancer

Besides histologic features, the presence of nodal metastasis is the most crucial prognostic factor for recurrence and survival for patients with gynecologic cancer. Conventionally, lymphadenectomy has been performed routinely to assess lymphatic metastasis. However, lymphadenectomy may be unnecessary in early-stage gynecologic cancer, because the percentage of patients with lymph node involvement is very low. The recent use of sentinel lymph node mapping has provided high feasibility, safety, and accuracy in the assessment of nodal metastasis. The National Comprehensive Cancer Network Clinical Practice Guidelines have incorporated the sentinel lymph node for nodal evaluation in vulvar, endometrial, and cervical cancers.

Ultrastaging protocol in sentinel lymph node for apparent early stage ovarian cancer

OBJECTIVE

The objective of the present study is to determine the role of sentinel lymph node (SLN) ultrastaging in apparent early-stage ovarian cancer.

METHODS

We previously demonstrated the feasibility of SLN in early-stage ovarian cancer in a pilot study and in a clinical trial (NCT03452982). The SLN of the 30 patients involved in both were processed following an ultrastaging protocol. The cost of ultrastaging processing was also reported.

RESULTS

A SLN was detected in up to 91.3% and 90% in the pelvic and para-aortic region, respectively. In all cases, a SLN was detected at least in one field, pelvic or para-aortic. The mean time from injection to SLN resection was 53.3 ± 20.3 min. Two of 30 (6.6%) patients had a contralateral SLN in the para-aortic field, but no patients had contralateral SLN within the pelvic field after injection. The mean number of harvested SLN was 2.1 ± 1.4 (range: 0-5) and 2.7 ± 1.5 (range: 0-7) in the pelvic and para-aortic region, respectively. Two patients were upgraded to stage IIIA1 because of lymph node metastasis. In the first case, based on single sections and haematoxylin and eosin (H&E) examination, a pelvic SLN micrometastasis (1 mm) was found on the first H&E section. By using the ultrastaging protocol, the size of the metastasis was increased to 2.1 mm (macrometastasis). In the same patient, the ultrastaging study of the inframesenteric para-cava SLNs found isolated tumour cells in the subcapsular and interfollicular lymph nodes sinus in one of the two SLN harvested (in one of the sections at the fourth and fifth ultrastage levels). The other upstaged case was a para-aortic macrometastasis in a patient in whom the SLN was not identified in the para-aortic field because of the absence of migration from the infundibulo-pelvic stump injection. The cost of ultrastaging in each patient depended on the total number of SLN retrieved, averaging 96.8 € (range: 0-230.5) and 124.5 € (range: 0-322.7€) for pelvic and para-aortic SLN, respectively.

CONCLUSIONS

A uniform protocol for ultrastaging is essential for lower-volume metastasis detection and to provide reproducible information between upcoming studies, as evidence about SLN in ovarian cancer is growing.

The role of sentinel-node biopsy in ovarian cancer

Lymph node involvement is an important prognostic factor in early and advanced epithelial ovarian cancer (EOC). However, to date there is no reliable method of detecting lymph node involvement, apart from surgical staging. Thus, pelvic and paraaortic lymphadenectomy (LNE) are still part of standard surgery of early ovarian cancer. There is conflicting evidence about the therapeutic value of systematic LNE in early EOC. Thus, the developmemt of a method to predict nodal status accurately, without extensive LNE, is the subject of ongoing research. Sentinel lymphadenectomy (SLN) has become a standard procedure in oncological surgery. However, SLN is not yet an established and widely accepted procedure for EOC. This review aimed at summarizing available evidence on its feasibility and reliability in EOC. Overall, evidence of SLN in early EOC is still scarce. So far, only small series of patients with a variety of tracers and injection sites were published. From the available literature, the most promising technique seems to be injection into the infundibulopelvic, as well as the proper ovarian ligament. Indocyanine green seems to be an excellent tracer for successful SLN of ovarian tumors, which can be used during laparoscopic or robotic surgery. The detection rates and true positive rates of studies support further investigation of the technique. Results from prospective studies, e.g. the ongoing SELLY trial, are necesssary to implement SLN into the standard treatment of early EOC.

Utility of Intraoperative Fluorescence Imaging in Gynecologic Surgery: Systematic Review and Consensus Statement

BACKGROUND

This study aimed to review the current knowledge on the utility of intraoperative fluorescence imaging in gynecologic surgery and to give evidence-based recommendations to improve the quality of care for women who undergo gynecologic surgery.

METHODS

A computer-based systematic review of the MEDLINE, CENTRAL, Pubmed, EMBASE, and SciSearch databases as well as institutional guidelines was performed. The time limit was set at 2000-2019. For the literature search, PRISMA guidelines were followed. A modified-Delphi method was performed in three rounds by a panel of experts to reach a consensus of conclusions and recommendations.

RESULTS

Indocyanine green (ICG) is used primarily in gynecology for sentinel node-mapping. In endometrial and cervical cancer, ICG is a feasible, safe, time-efficient, and reliable method for lymphatic mapping, with better bilateral detection rates. Experience in vulvar cancer is more limited, with ICG used together with Tc-99 m as a dual tracer and alone in video endoscopic inguinal lymphadenectomy. In early ovarian cancer, results are still preliminary but promising. Indocyanine green fluorescence imaging also is used for ureteral assessment, allowing intraoperative ureteral visualization, to reduce the risk of ureteral injury during gynecologic surgery.

CONCLUSIONS

For most gynecologic cancers, ICG fluorescence imaging is considered the tracer of choice for lymphatic mapping. The use of this new technology expands to a better ureteral assessment.

Sentinel lymph node technique in early-stage ovarian cancer (SENTOV): a phase II clinical trial

Objective

Early-stage ovarian cancer might represent an ideal disease scenario for sentinel lymph node application. Nevertheless, the published experience seems to be limited. Our objective was to assess the feasibility and safety concerns of sentinel lymph node biopsy in patients with clinical stage I–II ovarian cancer.

Methods

We conducted a prospective cohort study of 20 patients with histologically confirmed ovarian cancer. ^99mTc and indocyanine green were injected into both the utero-ovarian and infundibulopelvic ligament stump, if they were present, during surgical staging. An intraoperative gamma probe and near-infrared fluorescence imaging were used to detect the sentinel lymph nodes. Inclusion criteria included: >18 years of age, suspicious adnexal mass (unilateral or bilateral) at ultrasound and CT imaging or confirmed ovarian tumor after previous surgery (unilateral or bilateral salpingo-oophorectomy with or without hysterectomy). Adverse events were recorded through postoperative day 30. The primary trial end point was to report adverse events related to the technique, including the use of ^99mTc and ICG intraperitoneally, as well as the feasibility of the technique.

Results

A total of 20 patients were included in the analysis. Sentinel lymph nodes were detected in 14/15 (93%) pelvic and all 20 (100%) para-aortic regions. Five patients did not have utero-ovarian injection because of prior hysterectomy. The mean time from injection to sentinel lymph node resection was 53±15 min (range; 30–80). The mean number of harvested sentinel lymph nodes was 2.2±1.5 (range; 0–5) lymph nodes in the pelvis and 3.3±1.8 (range; 1–7) lymph nodes in the para-aortic region. There were no adverse intraoperative events, nor any within the 30 days of follow-up related with the technique.

Conclusion

Sentinel lymph node mapping in early-stage ovarian cancer is feasible without major intraoperative or < 30 days safety concerns. (NCT03452982).

Trial registration number

ClinicalTrials.gov, NCT03452982.

Sentinel Lymph Node Technique in Apparent Early Ovarian Cancer: Laparoscopic Technique

STUDY OBJECTIVE

To demonstrate the feasibility of laparoscopic sentinel lymph node technique in presumed early-stage ovarian cancer.

DESIGN

Video illustrating the laparoscopic performance of the sentinel lymph node technique in ovarian cancer.

SETTING

The Oncologic Gynecology Department at the University Hospital La Fe.

PATIENTS

Candidates for the technique presented an apparent early stage ovarian cancer. The technique was performed in the context of a clinical trial called SENTOV (NCT03452982).

INTERVENTIONS

To date, lymphadenectomy is recommended after the diagnosis of apparent early-stage ovarian cancer as part of the surgical staging. Minimally invasive surgery can be considered for the purpose of restaging [1]. Up to 14% of the patients are upstaged because of positive lymph nodes after pelvic and para-aortic lymphadenectomy [2]. Regarding low-grade tumors, a lower rate of lymph node involvement has been reported [3]. Sentinel lymph node technique has been reported to be feasible in a recent pilot study [4]. Two clinical trials (Sentinel Lymph Node in Early Ovarian Cancer and Sentine Lymph Node in Early Ovarian Cancer) are currently ongoing to clarify the use of sentinel lymph node technique in early ovarian cancer. The injection points were at the infundibulopelvic and ovarian ligament stumps. Two hundred microliters of saline solution containing 37 MBq of technetium-99m nanocolloid followed by 0.5 mL of indocyanine green (ICG) was injected subperitoneally. We used a 27 G needle at each injection point. Immediately after injection and also at 15 and 30 minutes after injection, the operative field was checked guided by the acoustic signal of the gamma probe and the near-infrared camera. We performed a minimum dissection looking for the sentinel lymph node or nodes in the pelvic and para-aortic region. Any lymph node with a remarkable radioactivity count as high as 10 times the background and/or dyed with ICG was considered a sentinel lymph node and was harvested separately. A systematic surgical staging was performed after the sentinel lymph node procedure was completed. Because of its small size, the ICG molecule is not caught in the lymph node valve system and keeps migrating when performing lymphography. An exhaustive direct view of the dye path is required to avoid misleading detection of the real sentinel lymph node. This theoretical problem is resolved by the use of the 99mTC-nanocolloid. This tracer gets trapped into the lymph node valve system because of its molecular size and does not keep migrating as does ICG. As such, a combination of both methods is proposed.

CONCLUSION

Laparoscopic performance of sentinel lymph node technique in ovarian cancer seems to achievable. Between 2017 and 2019, this procedure was performed in 30 patients (13 laparoscopic), in the context of our pilot experience [4] and the Sentinel Lymph Node in Early Ovarian Cancer clinical trial (NCT03452982).

Feasibility of sentinel lymph node mapping of the ovary: a systematic review

Pelvic and para-aortic lymphadenectomy is routinely performed in early ovarian cancer to define the stage of the disease. However, it may be associated with increased blood loss, operative time, and length of hospitalization. The sentinel lymph node technique has been shown to be safe and feasible in vulvar, uterine, and cervical cancer. Data detailing feasibility and outcomes of sentinel lymph node mapping in ovarian cancer are scarce.

To summarize the studies evaluating the feasibility of sentinel lymph node detection from the ovary, examining the technique and detection rate.

A systematic search of the literature was performed using PubMed and Embase from June 1991 to February 2019. Studies describing the sentinel lymph node technique and lymphatic drainage of the ovaries were incorporated in this review. Ten articles were selected, comprising a total of 145 patients. A variety of agents were used, but the primary markers were technetium-99m radiocolloid (Tc-99m), patent blue, or indocyanine green, and the most common injection site was the ovarian ligaments.

The overall sentinel lymph node detection rate was 90.3%.

We propose a standardized technique sentinel lymph node mapping in ovarian cancer, using indocyanine green, or Tc-99m and blue dye as alternative tracers, injected in both the suspensory and the infundibulopelvic ligament of the ovary.

The role of sentinel node in early ovarian cancer: a systematic review

INTRODUCTION

Early ovarian cancer (EOC) is defined as ovarian cancer macroscopically limited to the ovaries at the time of initial diagnosis. Approximately only 25% of patients with ovarian cancer are affected by EOC. This condition requires complete surgical staging, including systematic lymphadenectomy up to the level of the renal vessels, with the consequent risk of complications and morbidity. With the aim to reduce the procedure-related morbidity, sentinel lymph node mapping (SLNm) has been introduced as an experimental procedure in EOC staging. The aim of the present study is to systematically review the available series on this interesting issue.

EVIDENCE ACQUISITION

Studies were identified by searching electronic databases. The search was systematically applied to PubMed, ClinicalTrials.gov, Scopus and Web of Science looking for records describing the use of sentinel lymph node technique in EOC from January 1st, 1989 to January 1st, 2019. A total of 10 studies were identified for inclusion. Of the 121 patients involved in these studies, only 43 had a histologically-confirmed diagnosis of EOC and were included in the present analysis.

EVIDENCE SYNTHESIS

SLN (paraaortic and/or pelvic) overall detection rate (DR) was of 97.6%. The overall sensitivity (SS) and negative predictive value (NPV) of the included cases were 66.7% and 96.6%, respectively. We calculated also NPV, SS and DR based on the anatomical lymph node district, with a value of 100% both in the lumbo-aortic and in the pelvic district and a DR of 83.3% and 43% respectively.

CONCLUSIONS

This review shows that evidence on SLNm in EOC is still scant. Based on the limited data available, SLNm may provide potentially useful information on nodal status in patients affected by this disease.