Indocyanine green in gynecologic surgery: Where do we stand? A literature review and meta-analysis

The main objective of this study was to review and perform a meta-analysis of current literature on the use of indocyanine green for sentinel lymph node detection in pelvic gynecologic cancer. We included all studies focusing on indications and procedures associated with the use of ICG in gynecologic surgery and available on the Medline and Pubmed database. For the meta-analysis, random effect models were used for estimation of the 95 % detection rate and 95 % confidence interval, and stratified analyses by cancer type, concentration and localization of injection were performed. A total of 147 articles were included, of which 91 were studied in a meta-analysis. Results concerning detection rate by indocyanine green injection site were found to be 95.1 % and 97.3 % respectively for intracervical injection in 2 or 4 quadrants, and 77.0 % and 94.8 % for hysteroscopic and intradermal injection respectively. Results concerning detection rate by cancer type were 95.8 %, 95.2 %, 94.7 % and 95.7 % respectively for cervical, endometrial, vulvar and endometrial/cervical cancers. Finally, the results concerning detection rate by indocyanine green concentration were 91.2 %, 95.7 %, 96.7 % and 97.7 % for concentrations of <1.25 mg/ml, 1.25 mg/ml, 2.5 mg/ml and 5 mg/ml respectively. In conclusion, indocyanine green is shown to allow highlighting of sentinel lymph nodes with good reliability with an overall indocyanine green detection rate of 95.5 %. Our literature review revealed that indocyanine green feasibility has also been demonstrated in several surgical contexts, notably for reconstructive surgery and detection of endometriosis.

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.

Chlorophyll-Based Near-Infrared Fluorescent Nanocomposites: Preparation and Optical Properties

Near-infrared (NIR) fluorescence has attracted much attention in biomedical fields because it offers deep tissue penetration and high spatial resolution. Herein, a method is developed for the preparation of NIR fluorescent nanocomposites (NCs) by encapsulating natural chlorophyll (Chl) into the micelles of octylamine-modified poly(acrylic acid) (OPA). Both femtosecond transient absorption spectra and isothermal titration calorimetry thermogram reveal that the micelles of OPA provide a hydrophobic environment for the improved fluorescence efficiency. Hence the resulted Chl NCs possess unique properties such as ultrasmall size, outstanding photostability, good biocompatibility, and superbright NIR fluorescence emission. In vivo imaging of sentinel lymph node is achieved in nude mice, demonstrating the potential of Chl NCs in biomedical applications. This work provides a new strategy for the preparation of highly biocompatible NIR fluorescence labeling nanocomposites.

Pathologic Protocols for Sentinel Lymph Nodes Ultrastaging in Cervical Cancer

CONTEXT.—

Ultrastaging of sentinel lymph nodes (SLNs) is a crucial aspect in the approach to SLN processing. No consensual protocol for pathologic ultrastaging has been approved by international societies to date.

OBJECTIVE.—

To provide a review of the ultrastaging protocol and all its aspects related to the processing of SLNs in patients with cervical cancer.

DATA SOURCES.—

In total, 127 publications reporting data from 9085 cases were identified in the literature. In 24% of studies, the information about SLN processing is entirely missing. No ultrastaging protocol was used in 7% of publications. When described, the differences in all aspects of SLN processing among the studies and institutions are substantial. This includes grossing of the SLN, which is not completely sliced and processed in almost 20% of studies. The reported protocols varied in all aspects of SLN processing, including the thickness of slices (range, 1-5 mm), the number of levels (range, 0-cut out until no tissue left), distance between the levels (range, 40-1000 μm), and number of sections per level (range, 1-5).

CONCLUSIONS.—

We found substantial differences in protocols used for SLN pathologic ultrastaging, which can impact sensitivity for detection of micrometastases and even small macrometastases. Since the involvement of pelvic lymph nodes is the most important negative prognostic factor, such profound discrepancies influence the referral of patients to adjuvant radiotherapy and could potentially cause treatment failure. It is urgent that international societies agree on a consensual protocol before SLN biopsy without pelvic lymphadenectomy is introduced into routine clinical practice.

Radical parametrectomy after 'cut-through' hysterectomy in low-risk early-stage cervical cancer: Time to consider this procedure obsolete

OBJECTIVE

The goal of this study is to identify predictive factors in patients with a diagnosis of early-stage cervical cancer after simple hysterectomy in order to avoid a radical parametrectomy.

METHODS

A retrospective review was performed of all patients who underwent radical parametrectomy and bilateral pelvic lymphadenectomy at MD Anderson Cancer Center and at the Instituto de Cancerologia Las Americas in Medellin, Colombia from December 1999 to September 2017. We sought to determine the outcomes in patients diagnosed with low-risk factors (squamous, adenocarcinoma or adenosquamous lesions<2cm in size, and invading<10mm) undergoing radical parametrectomy and pelvic lymphadenectomy.

RESULTS

A total of 30 patients were included in the study. The median age was 40.4years (range; 26-60) and median body mass index (BMI) was 26.4kg/m² (range; 17.7-40.0). A total 22 patients had tumors<1cm and 8 had tumors between 1 and 2cm. A total of 6 (33%) of 18 patients had evidence of lymph-vascular invasion (LVSI). No radical parametrectomy specimen had residual tumor, involvement of the parametrium, vaginal margin positivity, or lymph node metastasis. None of the patients received adjuvant therapy. After a median follow-up of 99months (range; 6-160) only one patient recurred.

CONCLUSION

Radical parametrectomy may be avoided in patients with low-risk early-stage cervical cancer detected after a simple hysterectomy. Rates of residual disease (parametrial or vaginal) and the need for adjuvant treatments or recurrences are very low.

Can pelvic lymphadenectomy be omitted in patients with stage IA2, IB1, and IIA1 squamous cell cervical cancer?

Purpose

This study aimed to identify the surgical-pathologic risk factors of lymph node metastasis (LNM) in patients with early stage squamous cell cervical cancer and to evaluate the potential efficacy of omitting pelvic lymphadenectomy.

Methods

A total of 276 patients with stage IA2, IB1, and IIA1 squamous cell cervical cancer receiving primary radical hysterectomy with pelvic lymphadenectomy were included in this study.

Results

The incidences of LNM in patients with stage IA2, IB1, and IIA1 squamous cell cervical cancer were 0 % (0/8), 17.4 % (36/207), and 29.5 % (18/61), respectively. The most common location of LNM was the obturator lymph node. Human papilloma virus 16 subtype was the most common infection in early stage squamous cell cervical cancer. Univariate analysis revealed that squamous cell carcinoma antigen (SCCAg) greater than 1.5 μg/L (p < 0.001), tumor size greater than 2 cm (p < 0.001), tumor size greater than 3 cm (p < 0.001), depth of stromal invasion (p < 0.001) and lymphovascular invasion (p < 0.001) were associated with LNM. Logistic regression analysis revealed that depth of stromal invasion {model 1 [p = 0.006; odds ratio (OR) 2.161; 95 % confidence interval (CI) 1.251–3.734], model 2 [p = 0.002; OR 2.344; 95 % CI 1.337–3.989]}, lymphovascular invasion [model 1 (p = 0.004; OR 2.967; 95 % CI 1.411–6.237), model 2 (p = 0.004; OR 2.978; 95 % CI 1.421–6.243)], and SCCAg greater than 1.5 μg/L [model 1 (p = 0.023; OR 2.431; 95 % CI 1.129–5.235), model 2 (p = 0.024; OR 2.418; 95 % CI 1.125–5.194)] were independently associated with LNM.

Conclusions

Pelvic lymphadenectomy may be omitted in patients with SCCAg lower than 1.5 μg/L, superficial stromal invasion and without lymphovascular invasion in stage IA2, IB1, IIA1 squamous cell cervical cancer.

Sentinel Node Mapping in Cervical and Endometrial Cancer: Indocyanine Green Versus Other Conventional Dyes-A Meta-Analysis

BACKGROUND

Historically, blue dyes, (99)Tc or a combination of the two tracers have been used for sentinel lymph node (SLN) mapping in cervical and endometrial cancer patients. Indocyanine green (ICG), as a tracer, has been recently introduced in this setting. Our goal was to assess the differences in overall and bilateral detection rates as well as in false-negative rates among the different tracers.

METHODS

The electronic databases PubMed, MEDLINE, and Scopus were searched in January 2016 by searching the terms "sentinel lymph node" and "dye" and "indocyanine green," and "cervical cancer" or "endometrial cancer." Series comparing different tracers injected intracervically and reporting the detection rate and/or SLN false-negative rate were selected.

RESULTS

Forty-five studies were retrieved. Six studies including 538 patients met selection criteria. Compared with blue dyes, ICG SLN mapping had higher overall (odds ratio [OR] 0.27; 95 % confidence interval [CI] 0.15-0.50; p < 0.0001) and bilateral detection rates (OR 0.27; 95 % CI 0.19-0.40; p < 0.00001). No differences were found between ICG and (99)TC, although these results are based on data of a single series. No differences in overall and bilateral detection rates were found between ICG and the combination of blue dyes and (99)TC. The pooled analysis of false-negative rates data showed no difference in false-negative rates between tracers.

CONCLUSIONS

In cervical and endometrial cancer, ICG SLN mapping seems to be equivalent to the combination of blue dyes and (99)TC in terms of overall and bilateral detection rates. Its safety profile and ease of use may favor its employment respect to conventional tracers.