Staging laparoscopy with ultrasound and near-infrared fluorescence imaging to detect occult metastases of pancreatic and periampullary cancer

The role of indocyanine green in fluorescence-guided pancreatic surgery: a comprehensive review

Pancreatic surgery is a complex and challenging field, with patients facing a high risk of postoperative complications. In recent years, indocyanine green (ICG) has gained prominence as a valuable tool used in various aspects of pancreatic surgery. ICG is a fluorescent dye that offers real-time imaging capabilities that enhance the surgeon's ability to accurately localize tumors and critical anatomical structures, thereby improving surgical precision and potentially reducing operative time and complications. One of the most significant advantages of ICG is its ability to provide enhanced visualization of the biliary tract and vascular structures, which is particularly beneficial in complex pancreatic resections, in which the anatomy can be highly variable and challenging to navigate. Furthermore, ICG can be instrumental in ensuring the adequate perfusion of anastomoses, thereby reducing the risk of postoperative leaks and associated morbidity. This comprehensive review aims to provide an in-depth analysis of the current applications, advantages, and limitations of ICG in pancreatic surgery.

Fluorescence-guided pancreatic surgery: A scoping review

BACKGROUND

Although fluorescence guidance during various surgical procedures has been shown to be safe and have possible better clinical outcomes than without the guidance, the use of fluorophores in pancreatic surgery is novel and not yet well described. This scoping review involved a systematic methodology of the currently available literature and aimed to illuminate the use of fluorophores in pancreatic surgery from a clinical view.

METHODS

The PRISMA and the PRISMA-ScR guidelines were used when appropriate and the following databases were searched: PubMed, Embase, Scopus, The Cochrane Collection, and Web of Science. Human original articles and case reports were included. Bias was assessed with the Newcastle-Ottawa Scale and the IDEAL framework was used for evaluation of surgical innovation.

RESULTS

A total of 5,565 search hits were screened, and 23 original articles and 24 case reports consisting of 754 patients met the inclusion criteria. The use of indocyanine green was both the most prominent and the most promising method for securing sufficient perfusion of neighboring organs, enhancing the detection and distinguishing of neuroendocrine tumors, and assisting in the identification of hepatic micrometastases.

CONCLUSION

The included studies were generally heterogenic, exploratory, and small. Indocyanine green was used in several ways, and it may add clinical value in different settings during pancreatic surgery. Tumor-targeted probes are a rapidly developing and promising field of research.

Rising sun or strangled in the cradle? A narrative review of near-infrared fluorescence imaging-guided surgery for pancreatic tumors

Near-infrared fluorescence (NIRF)-guided surgical navigation has become a promising and effective detection method in pancreatic tumor surgery. The imaging technique has gradually transitioned from the NIR-I region to the NIR-II region. Real-time assessment of the tumor boundary and determination of the ideal resection plane are essential for preserving the pancreatic parenchyma and its secretory functions. However, since the pancreatic parenchyma has a less rich blood supply than the liver, the application of contrast agents in pancreatic tumor surgery is still in its infancy. The application of indocyanine green (ICG) and methylene blue (MB) in intraoperative NIRF imaging of pancreatic tumors has become more mature, but due to the characteristics of nonspecific imaging, the imaging efficiency and depth need to be improved. Many tumor-specific imaging agents have been designed, but most of them have not gone past animal trials because of their high development and imaging costs, biotoxicity, and other limitations. In this article, we review recent reports of ICG, MB, and newly developed contrast agents and imaging devices. We focus on the current status and new developments in the application of these contrast agents and summarize the current clinical and preclinical studies on specific contrast agents. We synthesize relevant reports to discuss the difficulties and prospects of the application of fluorescent imaging agents in pancreatic tumors. We hope that reviewing previous studies and the current progress on contrast imaging technology will provide new perspectives for its future application and development in pancreatic tumor surgery, which should translate into better patient prognoses. The manuscript was written according to the Scale for the Assessment of Narrative Review Articles (SANRA).

Near-infrared cholangiography can increase the chance of success in laparoscopic approaches to common bile duct stones, even with previous abdominal surgery

BACKGROUND

The treatment of common bile duct (CBD) stones with minimally invasive surgery (MIS) is more technical demanding than laparoscopic cholecystectomy (LC), especially in patients with history of previous abdominal surgery, cholangitis or cholecystitis. Near-infrared (NIR) cholangiography via systemic or biliary tree administration of indocyanine green (ICG), which enhances the visualization of the biliary tree anatomy, may increase the reassurance of CBD localization. The aim of this study was to identify the benefit of near-infrared cholangiography for laparoscopic common bile duct exploration (LCBDE).

METHODS

Three groups of CBD stone patients were included in this retrospective study depending on the surgical methods: 1) open choledocholithotomy (OCC), 2) laparoscopic choledocholithotomy (LCC), and 3) near-infrared cholangiography-assisted laparoscopic choledocholithotomy (NIR-CC). For the NIR-CC group, either 3 ml (concentration: 2.5 mg/mL) of ICG were intravenously administered or 10 ml (concentration: 0.125 mg/mL) of ICG were injected directly into the biliary tree. The enhancement rate of the cystic duct (CD), CBD, the upper and lower margin of the CBD were compared using white light image.

RESULTS

A total of 187 patients with a mean age of 68.3 years were included (OCC, n = 56; LCC, n = 110; NIR-CC, n = 21). The rate of previous abdominal surgery was significantly lower in the LCC group. The conversion rate was similar between the LCC and the NIR CC groups (p = 0.746). The postoperative hospital stay was significantly longer in the OCC group. No differences in morbidity and mortality were found between the three groups. In the NIR-CC group, the localization of CBD was as high as 85% compared to 24% with white light imaging.

CONCLUSIONS

Near-infrared cholangiography helps increase the chance of success in minimally invasive approaches to CBD stones even in patients with previous abdominal surgeries, without increasing the rate of conversion.

Consensus Statement on the Use of Near-Infrared Fluorescence Imaging during Pancreatic Cancer Surgery Based on a Delphi Study: Surgeons' Perspectives on Current Use and Future Recommendations

Indocyanine green (ICG) is one of the only clinically approved near-infrared (NIR) fluorophores used during fluorescence-guided surgery (FGS), but it lacks tumor specificity for pancreatic ductal adenocarcinoma (PDAC). Several tumor-targeted fluorescent probes have been evaluated in PDAC patients, yet no uniformity or consensus exists among the surgical community on the current and future needs of FGS during PDAC surgery. In this first-published consensus report on FGS for PDAC, expert opinions were gathered on current use and future recommendations from surgeons' perspectives. A Delphi survey was conducted among international FGS experts via Google Forms. Experts were asked to anonymously vote on 76 statements, with ≥70% agreement considered consensus and ≥80% participation/statement considered vote robustness. Consensus was reached for 61/76 statements. All statements were considered robust. All experts agreed that FGS is safe with few drawbacks during PDAC surgery, but that it should not yet be implemented routinely for tumor identification due to a lack of PDAC-specific NIR tracers and insufficient evidence proving FGS's benefit over standard methods. However, aside from tumor imaging, surgeons suggest they would benefit from visualizing vasculature and surrounding anatomy with ICG during PDAC surgery. Future research could also benefit from identifying neuroendocrine tumors. More research focusing on standardization and combining tumor identification and vital-structure imaging would greatly improve FGS's use during PDAC surgery.

Indocyanine Green Fluorescence-Guided Surgery for Gastrointestinal Tumors: A Systematic Review

Objective

To conduct a systematic review of the currently available literature on the use of ICG to guide surgical dissection in gastrointestinal (GI) cancer surgery.

Background

Real-time indocyanine green (ICG) fluorescence-guided surgery has the potential to enhance surgical outcomes by increasing patient-tailored oncological precision.

Methods

MEDLINE, PubMed, EMBASE, and Google Scholar were searched for publications on the use of ICG as a contrast agent in GI cancer surgery until December 2020. Perfusion studies were excluded. Quality of the studies was assessed with the Methodological Index for nonrandomized Studies or Jadad scale for randomized controlled trials. A narrative synthesis of the results was provided, with descriptive statistics when appropriate.

Results

Seventy-eight studies were included. ICG was used for primary tumor and metastases localization, for sentinel lymph node detection, and for lymph flow mapping. The detection rate for primary colorectal and gastric tumors was 100% after preoperative ICG endoscopic injection. For liver lesions, the detection rate after intravenous ICG infusion was 80% and up to 100% for lesions less than 8 mm from the liver surface. The detection rate for sentinel lymph nodes was 89.8% for esophageal, 98.6% for gastric, 87.4% for colorectal, and 83.3% for anal tumors, respectively. In comparative studies, ICG significantly increases the quality of D2 lymphadenectomy in oncological gastrectomy.

Conclusion

The use of ICG as a guiding tool for dissection in GI surgery is promising. Further evidence from high-quality studies on larger sample sizes is needed to assess whether ICG-guided surgery may become standard of care.

The Current Treatment Paradigm for Pancreatic Ductal Adenocarcinoma and Barriers to Therapeutic Efficacy

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, with a median survival time of 10-12 months. Clinically, these poor outcomes are attributed to several factors, including late stage at the time of diagnosis impeding resectability, as well as multi-drug resistance. Despite the high prevalence of drug-resistant phenotypes, nearly all patients are offered chemotherapy leading to modest improvements in postoperative survival. However, chemotherapy is all too often associated with toxicity, and many patients elect for palliative care. In cases of inoperable disease, cytotoxic therapies are less efficacious but still carry the same risk of serious adverse effects, and clinical outcomes remain particularly poor. Here we discuss the current state of pancreatic cancer therapy, both surgical and medical, and emerging factors limiting the efficacy of both. Combined, this review highlights an unmet clinical need to improve our understanding of the mechanisms underlying the poor therapeutic responses seen in patients with PDAC, in hopes of increasing drug efficacy, extending patient survival, and improving quality of life.

Indocyanine green fluorescence-guided intraoperative detection of peritoneal carcinomatosis: systematic review

BACKGROUND

To review the available clinical data about the value of Indocyanine Green (ICG) fluorescence imaging for intraoperative detection of peritoneal carcinomatosis.

METHODS

We conducted a systematic review, according to the PRISMA guidelines, for clinical series investigating the possible role of ICG fluorescence imaging in detecting peritoneal carcinomatosis during surgical treatment of abdominal malignancies. With the aim to analyze actual application in the daily clinical practice, papers including trials with fluorophores other than ICG, in vitro and animals series were excluded. Data on patients and cancer features, timing, dose and modality of ICG administration, sensitivity, specificity and accuracy of fluorescence diagnosis of peritoneal nodules were extracted and analyzed.

RESULTS

Out of 192 screened papers, we finally retrieved 7 series reporting ICG-guided detection of peritoneal carcinomatosis. Two papers reported the same cases, thus only 6 series were analyzed, for a total of 71 patients and 353 peritoneal nodules. The investigated tumors were colorectal carcinomas in 28 cases, hepatocellular carcinoma in 16 cases, ovarian cancer in 26 cases and endometrial cancer in 1 case. In all but 4 cases, the clinical setting was an elective intervention in patients known as having peritoneal carcinomatosis. No series reported a laparoscopic procedure. Technical data of ICG management were consistent across the studies. Overall, 353 lesions were harvested and singularly evaluated. Sensitivity varied from 72.4 to 100%, specificity from 54.2 to 100%. Two series reported that planned intervention changed in 25 and 29% of patients, respectively.

CONCLUSION

Indocyanine Green based fluorescence of peritoneal carcinomatosis is a promising intraoperative tool for detection and characterization of peritoneal nodules in patients with colorectal, hepatocellular, ovarian carcinomas. Further prospective studies are needed to fix its actual diagnostic value on these and other abdominal malignancies with frequent spread to peritoneum.

Optical and Optoacoustic Imaging Probes

Tissue has characteristic properties when it comes to light absorption and scattering. For optical (OI) and optoacoustic imaging (OAI) these properties can be utilised to visualise biological tissue characteristics, as, for example, the oxygenation state of haemoglobin alters the optical and optoacoustic properties of the molecule.

A prospective single-center protocol for using near-infrared fluorescence imaging with indocyanine green during staging laparoscopy to detect small metastasis from pancreatic cancer

Background

Pancreatic resection and radiotherapy are powerful tools in the multidisciplinary local treatment of pancreatic ductal adenocarcinoma (PDAC). However, 10–20% of patients with preoperatively resectable PDAC have radiographically occult metastases, which results in laparotomy without resection. This study aims to explore the utility of intraoperative near-infrared (NIR) imaging with indocyanine green (ICG) during staging laparoscopy to detect PDAC metastasis.

Methods

This prospective study will evaluate patients with radiographically non-metastatic PDAC before they undergo planned pancreatic resection or chemoradiotherapy. Enrolled patients will receive ICG intravenously (0.5 mg/kg) before the staging laparoscopy. During the staging laparoscopy, the abdominal cavity will be observed using standard white-light laparoscopic imaging and then using NIR-ICG imaging. Suspicious lesions that are detected using standard imaging and/or NIR-ICG imaging will be examined intraoperatively using frozen sections and permanent specimens. We will evaluate the benefit of NIR-ICG imaging based on its ability to identify additional liver or peritoneal lesions that were not detected during standard white-light imaging.

Discussion

This study will help establish the clinical utility of NIR-ICG imaging to more precisely identify metastases from radiographically non-metastatic PDAC. This approach may help avoid needless major surgery or radiotherapy.

Trial registration

This protocol was registered on April 1, 2017 on the UMIN Clinical Trials Registry: UMIN000025900 and February 26, 2019 on the Japan Registry of Clinical Trials: jRCT1051180076.

Fluorescent-guided surgery for sentinel lymph node detection in gastric cancer and carcinoembryonic antigen targeted fluorescent-guided surgery in colorectal and pancreatic cancer

Sentinel lymph node procedures for gastric cancer resections using indocyanine green (ICG) linked to Nanocoll outperformed normal ICG but did not provide information on possible lymph node metastasis. Carcinoembryonic antigen targeted fluorescent imaging using SGM‐101 was successful in both pancreatic and colorectal cancer. A large phase III multicentre trial will soon be initiated in colorectal cancer patients.