A feasibility study of sentinel lymph node mapping by cervical injection of a tracer in Japanese women with early stage endometrial cancer

Risk factors associated with false negative rate of sentinel lymph node biopsy in endometrial cancer: a systematic review and meta-analysis

Objective

Currently, sentinel lymph node biopsy (SLNB) is increasingly used in endometrial cancer, but the rate of missed metastatic lymph nodes compared to systemic lymph node dissection has been a concern. We conducted a systematic review and meta-analysis to evaluate the false negative rate (FNR) of SLNB in patients with endometrial cancer and to explore the risk factors associated with this FNR.

Data sources

Three databases (PubMed, Embase, Web of Science) were searched from initial database build to January 2023 by two independent reviewers.

Research eligibility criteria

Studies were included if they included 10 or more women diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage I or higher endometrial cancer, the study technique used sentinel lymph node localization biopsy, and the reported outcome metrics included false negative and/or FNR.

Study appraisal and synthesis methods

Two authors independently reviewed the abstracts and full articles. The FNR and factors associated with FNR were synthesized through random-effects meta-analyses and meta-regression.

The results

We identified 62 eligible studies. The overall FNR for the 62 articles was 4% (95% CL 3-5).There was no significant difference in the FNR in patients with high-risk endometrial cancer compared to patients with low-risk endometrial cancer. There was no difference in the FNR for whether frozen sections were used intraoperatively. The type of dye used intraoperatively (indocyanine green/blue dye) were not significantly associated with the false negative rate. Cervical injection reduced the FNR compared with alternative injection techniques. Indocyanine green reduced the FNR compared with alternative Tc-99m. Postoperative pathologic ultrastaging reduced the FNR.

Conclusions

Alternative injection techniques (other than the cervix), Tc-99m dye tracer, and the absence of postoperative pathologic ultrastaging are risk factors for a high FNR in endometrial cancer patients who undergo SLNB; therefore, we should be vigilant for missed diagnosis of metastatic lymph nodes after SLNB in such populations.

Systematic review registration

http://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023433637.

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.

Predictors for the Recurrence of Clinically Uterine-Confined Endometrial Cancer and the Role of Cytokeratin Immunohistochemistry Stain in the Era of Sentinel Lymph Node Mapping

Simple Summary

Sentinel lymph node (SLN) mapping in women with endometrial cancer is gradually gaining popularity worldwide. The objectives of this retrospective study were to elucidate the predictors for cancer recurrence in the era of SLN mapping, and to compare the clinical outcomes between SLN mapping and traditional lymphadenectomy, as well as to investigate the role of cytokeratin immunohistochemistry stain in detecting lymph node metastases. Para-aortic lymph node metastasis was found to be the sole predictor for cancer recurrence. Cytokeratin immunohistochemistry stain detects more lymph node metastases. In addition, both SLN mapping and traditional lymphadenectomy have similar probabilities of cancer recurrence.

Abstract

Background: The primary objective of this study was to elucidate the predictors for cancer recurrence in women with clinically uterine-confined endometrial cancer in the era of sentinel lymph node (SLN) mapping. Methods: All consecutive women with clinically determined uterine-confined endometrial cancer who had lymph node assessment by either SLN mapping or traditional pelvic lymphadenectomy were reviewed. Results: Women in the SLN mapping group had lower total dissected pelvic nodes, lower incidence of para-aortic lymph node dissection, less intraoperative blood loss and lower complication rates, but a longer operation time compared to the traditional lymphadenectomy group. Para-aortic lymph node metastasis (hazard ratio = 7.60, p = 0.03) was the sole independent predictor for recurrence-free survival. In addition, the utilization of cytokeratin immunohistochemistry stain detected more lymph node metastases (adjusted odds ratio = 3.04, p = 0.03). Recurrence-free survival did not differ between SLN mapping and traditional lymphadenectomy groups (p = 0.24). Conclusions: Para-aortic lymph node metastasis is an important predictor of cancer recurrence. Women with negative hematoxylin and eosin stain should undergo cytokeratin immunohistochemistry stain to increase the detection rate of positive lymph node metastasis. Besides, the probabilities of recurrence seem to be similar between SLN mapping and traditional lymphadenectomy groups in women with clinically uterine-confined endometrial cancer.

Sentinel node biopsy for diagnosis of lymph node involvement in endometrial cancer

BACKGROUND

Pelvic lymphadenectomy provides prognostic information for those diagnosed with endometrial (womb) cancer and provides information that may influence decisions regarding adjuvant treatment. However, studies have not shown a therapeutic benefit, and lymphadenectomy causes significant morbidity. The technique of sentinel lymph node biopsy (SLNB), allows the first draining node from a cancer to be identified and examined histologically for involvement with cancer cells. SLNB is commonly used in other cancers, including breast and vulval cancer. Different tracers, including colloid labelled with radioactive technetium-99, blue dyes, e.g. patent or methylene blue, and near infra-red fluorescent dyes, e.g. indocyanine green (ICG), have been used singly or in combination for detection of sentinel lymph nodes (SLN).

OBJECTIVES

To assess the diagnostic accuracy of sentinel lymph node biopsy (SLNB) in the identification of pelvic lymph node involvement in women with endometrial cancer, presumed to be at an early stage prior to surgery, including consideration of the detection rate.

SEARCH METHODS

We searched MEDLINE (1946 to July 2019), Embase (1974 to July 2019) and the relevant Cochrane trial registers.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of tracers for SLN assessment (involving the identification of a SLN plus histological examination) against a reference standard of histological examination of removed pelvic +/- para-aortic lymph nodes following systematic pelvic +/- para-aortic lymphadenectomy (PLND/PPALND) in women with endometrial cancer, where there were sufficient data for the construction of two-by-two tables.

DATA COLLECTION AND ANALYSIS

Two review authors (a combination of HN, JM, NW, RG, and WH) independently screened titles and abstracts for relevance, classified studies for inclusion/exclusion and extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We calculated the detection rate as the arithmetic mean of the total number of SLNs detected out of the total number of women included in the included studies with the woman as the unit of analysis, used univariate meta-analytical methods to estimate pooled sensitivity estimates, and summarised the results using GRADE.

MAIN RESULTS

The search revealed 6259 unique records after removal of duplicates. After screening 232 studies in full text, we found 73 potentially includable records (for 52 studies), although we were only able to extract 2x2 table data for 33 studies, including 2237 women (46 records) for inclusion in the review, despite writing to trial authors for additional information. We found 11 studies that analysed results for blue dye alone, four studies for technetium-99m alone, 12 studies that used a combination of blue dye and technetium-99m, nine studies that used indocyanine green (ICG) and near infra-red immunofluorescence, and one study that used a combination of ICG and technetium-99m. Overall, the methodological reporting in most of the studies was poor, which resulted in a very large proportion of 'unclear risk of bias' ratings. Overall, the mean SLN detection rate was 86.9% (95% CI 82.9% to 90.8%; 2237 women; 33 studies; moderate-certainty evidence). In studies that reported bilateral detection the mean rate was 65.4% (95% CI 57.8% to 73.0%) . When considered according to which tracer was used, the SLN detection rate ranged from 77.8% (95% CI 70.0% to 85.6%) for blue dye alone (559 women; 11 studies; low-certainty evidence) to 100% for ICG and technetium-99m (32 women; 1 study; very low-certainty evidence). The rates of positive lymph nodes ranged from 5.2% to 34.4% with a mean of 20.1% (95% CI 17.7% to 22.3%). The pooled sensitivity of SLNB was 91.8% (95% CI 86.5% to 95.1%; total 2237 women, of whom 409 had SLN involvement; moderate-certainty evidence). The sensitivity for of SLNB for the different tracers were: blue dye alone 95.2% (95% CI 77.2% to 99.2%; 559 women; 11 studies; low-certainty evidence); Technetium-99m alone 90.5% (95% CI 67.7% to 97.7%; 257 women; 4 studies; low-certainty evidence); technetium-99m and blue dye 91.9% (95% CI 74.4% to 97.8%; 548 women; 12 studies; low-certainty evidence); ICG alone 92.5% (95% CI 81.8% to 97.1%; 953 women; 9 studies; moderate-certainty evidence); ICG and blue dye 90.5% (95% CI 63.2.6% to 98.1%; 215 women; 2 studies; low-certainty evidence); and ICG and technetium-99m 100% (95% CI 63% to 100%; 32 women; 1 study; very low-certainty evidence). Meta-regression analyses found that the sensitivities did not differ between the different tracers used, between studies with a majority of women with FIGO stage 1A versus 1B or above; between studies assessing the pelvic lymph node basin alone versus the pelvic and para-aortic lymph node basin; or between studies that used subserosal alone versus subserosal and cervical injection. It should be noted that a false-positive result cannot occur, as the histological examination of the SLN is unchanged by the results from any additional nodes removed at systematic lymphadenectomy.

AUTHORS' CONCLUSIONS

The diagnostic test accuracy for SLNB using either ICG alone or a combination of a dye (blue or ICG) and technetium-99m is probably good, with high sensitivity, where a SLN could be detected. Detection rates with ICG or a combination of dye (ICG or blue) and technetium-99m may be higher. The value of a SLNB approach in a treatment pathway, over adjuvant treatment decisions based on uterine factors and molecular profiling, requires examination in a high-quality intervention study.

Radical Hysterectomy After Neoadjuvant Chemotherapy for Locally Bulky-Size Cervical Cancer: A Retrospective Comparative Analysis between the Robotic and Abdominal Approaches

Radical hysterectomy (RH) is the standard treatment for early stage cervical cancer, but the surgical approach for locally bulky-size cervical cancer (LBS-CC) is still unclear. We retrospectively compared the outcomes of women with LBS-CC treated with neoadjuvant chemotherapy (NACT) and subsequent RH between the robotic (R-RH) and abdominal approaches (A-RH). Between 2012 and 2014, 39 women with LBS-CC FIGO (International Federation of Gynecology and Obstetrics) stage IB2–IIB were treated with NACT-R-RH (n = 18) or NACT-A-RH (n = 21). Surgical parameters and prognosis were compared. Patient characteristics were not significantly different between the groups, but the NACT-R-RH group had significantly more patients with FIGO stage IIB disease, received multi-agent-based NACT, and had a lower percentage of deep stromal invasion than the NACT-A-RH group. After NACT-R-RH, surgical parameters were better, but survival outcomes, such as disease-free survival (DFS) and overall survival (OS), were significantly worse. On multivariate analysis, FIGO stage IIB contributed to worse DFS (p = 0.003) and worse OS (p = 0.012) in the NACT-A-RH group. Women with LBS-CC treated with NACT-R-RH have better perioperative outcomes but poorer survival outcomes compared with those treated with NACT-A-RH. Thus, patients with FIGO stage IIB LBS-CC disease might not be suitable for surgery after multi-agent-based NACT.

Sentinel Lymph Nodes in Endometrial Cancer Update 2018

There are no established data about lymphadenectomy during treatment of endometrial cancers (ECs) and to what extent lymphadenectomy should be performed. In addition, retroperitoneal lymphadenectomy increases the intraoperative and postoperative complications. Sentinel lymph node (SLN) mapping has the lowest costs and highest quality-adjusted survival. SLN is the most cost-effective strategy in the management of low-risk ECs. Women staged with SLN mapping were more likely to receive adjuvant treatment compared with women staged with systemic lymphadenectomy. This review article designed to evaluate the diagnostic accuracy and the methods of SLN detection in ECs.