Elsevier

Gynecologic Oncology

Volume 124, Issue 1, January 2012, Pages 78-82
Gynecologic Oncology

Robotically assisted fluorescence-guided lymph node mapping with ICG for gynecologic malignancies: A feasibility study

https://doi.org/10.1016/j.ygyno.2011.09.025Get rights and content

Abstract

Objective

Traditional techniques of sentinel lymph node (SLN) mapping for endometrial and cervical cancer present challenges which may be overcome with newer technologies such as near infrared (NIR) imaging of the fluorescent dye Indocyanine green (ICG). We performed a feasibility and dose-finding study to define the dose of ICG required to identify pelvic and para-aortic sentinel lymph nodes with robotically assisted endoscopic NIR imaging after cervical injection.

Methods

20 subjects with cervical or endometrial carcinoma were prospectively enrolled for SLN mapping. ICG was injected into the cervical stroma at 3 o'clock and 9 o'clock Data was collected for the number of nodes identified, the location of SLN's, the duration of procedure and the pathology characteristics of the SLN's compared to the non-sentinel lymph nodes.

Results

20 subjects received cervical injection with at least one SLN observed in 17 subjects. 15 of the 17 subjects who received 1 mg injections of ICG mapped a SLN for an observed detection rate of 88% (95% CI is (64%,99%)). A median of 4.5 SLN's was identified per patient. Three patients had lymphatic metastases, one of whom had a positive SLN. No adverse events were identified.

Conclusions

A 1 mg cervical injection of ICG identified a SLN in 88% of patients (95% CI is (64%, 99%)). Robotically assisted fluorescence imaging is a feasible, safe, time efficient and reliable method for lymphatic mapping in early stage cervical and endometrial cancer.

Highlights

► This study evaluates a novel technique for robotic lymph node mapping with near infrared imaging. ► A 1mg cervical Indocyanine green injection revealed a fluorescent sentinel lymph node in 88% of patients. ► Operating room times were not increased and no adverse events occurred.

Introduction

Lymphadenectomy is important in the surgical management of cervical and endometrial cancers, however, it is associated with long-term complications such as lymphedema, nerve injury and lymphocyst formation [1], [2], [3]. Minimally invasive surgical approaches have been shown to reduce peri-operative morbidities for radical hysterectomy and endometrial cancer staging [4], [5]. Sentinel lymph node (SLN) sampling may reduce the risk of long-term complications for patients with cervical and endometrial cancer by minimizing lymphatic disruption.

SLN biopsy is effective in detecting metastatic disease for melanoma, breast and vulvar cancer surgeries [6], [7], [8]. Traditional methods of sentinel node mapping use peri-tumoral injections of blue dyes and/or radioactive tracers. SLN's are identified intra-operatively with Geiger counters or visualization of blue lymph nodes. These methods have been applied to open and minimally invasive SLN detection for cervical and endometrial cancer and their results are promising to date [9], [10], [11]. However, these techniques are challenging to master with prolonged learning curves [12]. Medical dyes that fluoresce and are detected by specialized imagers are a promising alternative to the traditional modalities. They have been tested in gastric, breast and rectal cancers with preliminary results comparable to traditional techniques of SLN mapping [13], [14], [15]. Fluorescence imaging for SLN mapping has also been piloted for cervical cancer via laparotomy and open imagers with favorable results [16], [17].

We assessed the feasibility of a novel method of lymph node mapping using cervical injection of the fluorescing dye Indocyanine green (ICG) and endoscopic NIR imagers with robotic assistance. The primary objective was to determine the dose of ICG at which a minimum of one lymph node was mapped in 80% of subjects.

Section snippets

Methods

Permission was obtained from the Institutional Review Board and UNC Lineberger Comprehensive Cancer Center Protocol Review Committee to perform a prospective cohort study of 20 women with a pre-operative diagnosis of clinical stage 1 endometrial or cervical cancer. Patients consented to cervical stromal injections of ICG, a nontoxic, sterile, water-soluble tricarbocyanine dye, at the time of their definitive surgery. All subjects had planned bilateral pelvic and, in the case of endometrial

Results

Cervical ICG injections and robotically assisted SLN mapping were performed on 20 patients, including 16 patients with a preoperative diagnosis of endometrial cancer and 4 with cervical cancer. Nine (55%) of the sixteen patients with a preoperative diagnosis of endometrial cancer had a grade 1 lesion, with the remaining seven having high grade, type two or non-endometrial pathologies. Three of the four patients with cervical cancer had adenocarcinoma, with 1 having squamous cell carcinoma. The

Discussion

Lymphadenectomy is an important component of the surgical management of cervical and endometrial cancer. Lymph node status is a major factor determining prognosis for early stage cervical cancer [18]. While the role of lymphadenectomy for endometrial cancer is more controversial, ACOG recommends that “most women” with endometrial cancer should receive lymphadenectomy [19].

However, retroperitoneal lymphadenectomy is not without risk. It is associated with a 3.4 to 7.2% risk of lower extremity

Conclusions

Robotically assisted fluorescence imaging is a feasible, safe, reliable and time efficient method for lymphatic mapping and identification of SLN's. SLN's are identified in 88% of patients receiving a 1 mg injection of ICG into the uterine cervix. Subsequent studies with larger numbers of patients are required to determine if the nodes identified with this technique are able to sensitively predict metastatic disease.

Conflict of interest statement

The authors have no conflicts of interest to disclose.

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