[Fluorescence-guided detection of lymph node metastases of gastrointestinal tumors]

History and evidence for state of the art of lymphadenectomy in esophageal cancer surgery

The current curative multimodal treatment of advanced esophageal cancers consists of neoadjuvant or perioperative chemo(radio)therapy followed by a radical surgical resection of the primary tumor and a 2- or 3-field lymphadenectomy. One of the most important predictors of long-term survival of esophageal cancer patients is lymph node involvement. The distribution pattern of lymph node metastases in esophageal cancer is unpredictable and depends on the primary tumor location, histology, T-stage and application of neoadjuvant or perioperative treatment. The optimal extent of the lymphadenectomy remains controversial; there is no global consensus on this topic yet. Some surgeons advocate an aggressive and extended lymph node dissection to remove occult metastatic disease, to optimize oncological outcomes. Others promote a more restricted lymphadenectomy, since the benefit of an extended lymphadenectomy, especially after neoadjuvant chemoradiotherapy, has not been clearly demonstrated, and morbidity may be reduced. In this review, we describe the development of lymphadenectomy, followed by a summary of current evidence for lymphadenectomy in esophageal cancer treatment.

Fluorescence-based sentinel lymph node mapping and lymphography evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

The identification of metastatic lymph nodes is one of the most important prognostic factors in gastrointestinal (GI) cancers. Near-infrared fluorescence (NIRF) imaging has been successfully used in GI tumors to detect the lymphatic pathway and the sentinel lymph node (SLN), facilitating fluorescence image-guided surgery (FIGS) with the purpose to achieve a correct nodal staging. The aim of this study was to analyze the current results of NIRF SLN navigation and lymphography through data collected in the EURO-FIGS registry.

METHODS

Prospectively collected data regarding patients and ICG-guided lymphadenectomies were analyzed. Additional analyses were performed to identify predictors of metastatic SLN and determinants of fluorescence positivity and nodal metastases outside the boundaries of standard lymphadenectomies.

RESULTS

Overall, 188 patients were included by 18 surgeons from 10 different centers. Colorectal cancer was the most reported pathology (77.7%), followed by gastric (19.1%) and esophageal tumors (3.2%). ICG was injected with higher doses (p < 0.001) via extraparietal side (63.3%), and with higher volumes (p < 0.001) via endoluminal side (36.7%). Overall, NIRF SLN navigation was positive in 75.5% of all cases and 95.5% of positive SLNs were retrieved, with a metastatic rate of 14.7%. NIRF identification of lymph nodes outside standard lymphatic stations occurred in 52.1% of all cases, 43.8% of which were positive for metastatic involvement. Positive NIRF SLN identification was an independent predictor of metastasis outside standard lymphatic stations (OR = 4.392, p = 0.029), while BMI independently predicted metastasis in retrieved SLNs (OR = 1.187, p = 0.013). Lower doses of ICG were protective against NIRF identification outside standard of care lymphadenectomy (OR = 0.596, p = 0.006), while higher volumes of ICG were predictive of metastatic involvement outside standard of care lymphadenectomy (OR = 1.597, p = 0.001).

CONCLUSIONS

SLN mapping helps identifying potentially metastatic lymph nodes outside the boundaries of standard lymphadenectomies. The EURO-FIGS registry is a valuable tool to share and analyze European surgeons' practices.

Characterization of Near-Infrared Imaging and Indocyanine-Green Use Amongst General Surgeons: A Survey of 263 General Surgeons

BACKGROUND

Near-infrared fluorescence imaging (NIRFI) is an increasingly utilized imaging modality, however its use amongst general surgeons and its barriers to adoption have not yet been characterized.

METHODS

This survey was sent to Canadian Association of General Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons members. Survey development occurred through consensus of NIRFI experienced surgeons.

RESULTS

Survey completion rate for those opening the email was 16.0% (n = 263). Most respondents had used NIRFI (n = 161, 61.2%). Training, higher volumes, and bariatric, thoracic, or foregut subspecialty were associated with use (P < .001).Common reasons for NIRFI included anastomotic assessment (n = 117, 72.7%), cholangiography (n = 106, 65.8%), macroscopic angiography (n = 66, 41.0%), and bowel viability assessment (n = 101, 62.7%). Technical knowledge, training and poor evidence were cited as common barriers to NIRFI adoption.

CONCLUSIONS

NIRFI use is common with high case volume, bariatric, foregut, and thoracic surgery practices associated with adoption. Barriers to use appear to be lack of awareness, low confidence in current evidence, and inadequate training. High quality randomized studies evaluating NIRFI are needed to improve confidence in current evidence; if deemed beneficial, training will be imperative for NIRFI adoption.

[Evidence of indocyanine green fluorescence in robotically assisted colorectal surgery : What is the status?]

BACKGROUND

Indocyanine green (ICG) fluorescence imaging is increasingly being used in various areas of abdominal surgery. The constant improvement in the technology enables easy intraoperative use and progressively influences operative decision-making, also in robotically assisted colorectal surgery.

OBJECTIVE

Summation of current evidence on the use of ICG fluorescence imaging in robotically assisted colorectal surgery.

MATERIAL AND METHODS

The assessment of evidence is based on a comprehensive literature search (PubMed).

RESULTS

First individual studies (feasibility, case matched, prospective cohort, multicenter phase II, single center randomized controlled study/trial) showed a significant reduction in the incidence of anastomotic leakage (AL) after colorectal anastomosis through the use of ICG fluorescence angiography (FA, 9.1% vs. 16.3%; p = 0.04). First feasibility studies demonstrated lymph node detection or navigation as well as ureter visualization.

CONCLUSION

The ICG-FA reliably detects tissue perfusion, quickly and effectively with few side effects. It can influence intraoperative decision-making and reduce AL rates. In addition, patients may be offered more precise tumor therapy via ICG sentinel lymph node (SLN) detection and lateral pelvic lymph node (LPN) mapping and navigation. Iatrogenic lesions, such as ureteral injuries can be sufficiently prevented by appropriate visualization; however, valid data in order to be able to derive standardized operative consequences require further convincing multicenter, randomized controlled trials (mRCT).

Upstaging nodal status in colorectal cancer using ex vivo fluorescence sentinel lymph node mapping: preliminary results

BACKGROUND

Sentinel lymph node (SLN) mapping using near-infrared fluorescence (NIRF) imaging is a recent technique to improve nodal staging in several tumors. The presence of colorectal cancer (CRC) micro-metastases has recently been defined as N1 disease and no longer as N1mi, determining the need for adjuvant chemotherapy. In CRC, the reported rate of SLN micro-metastases detected by ultrastaging techniques is as high as 30%. The aim of this prospective study is to report the preliminary results of the sensitivity analysis of NIRF imaging for ex vivo SLN mapping and the research of micro-metastases in CRC, in patients with node-negative disease (NND).

MATERIAL AND METHODS

On the specimen of 22 CRC patients, 1 mL of ICG (5 mg/mL) was injected submucosally around the tumor to identify SLNs. NND SLNs were further investigated with ultrastaging techniques.

RESULTS

Three-hundred and sixty-three lymph nodes were retrieved (59 SLNs; mean per case: 2.7). The detection, sensitivity and false-negative rate were 100%, 100% and 0% respectively. Ultrastaging investigations showed no micro-metastases in the NND SLNs.

CONCLUSIONS

The ex vivo SLN fluorescence-based detection in CRC was confirmed to be easy to perform and reliable. In this preliminary results report of an ongoing study, the SLN assay was congruent with the nodal status, as confirmed by histological investigations.

Intra-arterial versus negative-staining of embryonal resection borders with indocyanine green (ICG) fluorescence for total mesorectal excision in colorectal cancer - an experimental feasibility study in a porcine model

Background: Colorectal cancer (CRC) is one of the most common malignancies worldwide. Laparoscopic lower rectal resections in accordance with the oncological principles are recommended as the gold standard for CRC surgical management. However, the learning curve for adopting these techniques is quite steep and the incomplete resections are predictive of local recurrence. This study was conducted in an attempt to find a way to help surgeons to overcome some of these difficulties and define the right resection margins.Material and methods: As such, we carried out two laparoscopic lower rectal resections in porcine models. The first resection was performed following the ligation and selective infusion of Indocyanine Green (ICG) into the inferior mesenteric artery (IMA), and the second after the ligation of both inferior mesenteric artery and vein (IMV) and systemic intravenous infusion of ICG. Fluorescence was detected in real time by means of an infrared imaging system.Results: Sharp resection margins were defined after intra-arterial infusion, and all the tissues in the IMA basin were colored in the first case. In the second model every organ and tissue was colored except the rectum, urinary bladder and ductus deferens.Conclusions: Although systemic intra-venous application of ICG and negative-staining of the rectum including the mesorectum is much easier compared to laparoscopic inter-arterial perfusion through IMA, image results of selevtive IMA-perfusion appear in sharper discrimination of the several layers. Further investigation should focus on simplifying this technique.