Fluorescence-guided cancer surgery-A new paradigm

Feasibility and efficacy of indocyanine green in monitoring systemic drug leakage during isolated limb perfusion for recurrent melanoma of extremity

Melanoma is known for its high metastatic potential and aggressive growth. Recurrence is common post-surgery, sometimes leading to unresectable disease. Locally recurrent unresectable melanoma of extremity has been treated with high-dose anticancer chemotherapy via isolated limb perfusion (ILP) to improve local efficacy of drug and salvage limbs. Standard ILP monitoring uses radiolabeled dyes, requiring specialized personnel and involving radiation exposure. In this case, we used indocyanine green (ICG) to track systemic drug leakage during ILP. A 47-year-old gentleman with recurrent malignant melanoma of the left foot, operated twice earlier and treated with adjuvant pembrolizumab, presented with multiple in-transit metastases in the limb. ILP was planned, with 5 mg ICG administered in the perfusion solution along with high-dose melphalan. Stryker's SPI PHI handheld device was employed to visualize ICG during ILP. Absence of fluorescence beyond the involved extremity, such as fingers, ears, and the abdominal wall, indicated no systemic drug dispersion. For control, technetium radiocolloid dye was co-administered, monitored by a precordial gamma probe, confirming no systemic leakage, and validating effectiveness of ICG in leakage monitoring. ICG proves to be a safe, reliable, cost-effective, radiation-free approach for precise systemic drug leakage monitoring during ILP for recurrent melanoma of extremity.

Autofluorescence of Parathyroid Glands: A Review of Methods of Parathyroid Gland Identification and Parathyroid Vascular Assessment

Postoperative hypoparathyroidism may cause significant patient morbidity and even mortality. Emerging technologies centered on autofluorescent properties of parathyroid glands when exposed to near-infrared light hold promise to improve surgical parathyroid gland identification and preservation. Two systems (probe-based and camera-based) are commercially available currently; however, neither system alone provides indication of vascular viability or postoperative parathyroid gland function. The administration of indocyanine green, when combined with near-infrared fluorescence imaging, enables subjective assessment of parathyroid gland perfusion. Additional technologies to assess parathyroid gland perfusion are being developed. The impact of these nascent technologies on relevant clinical outcomes is an area of active investigation.

Current status of indocyanine green fluorescent angiography in assessing perfusion of gastric conduit and oesophago-gastric anastomosis

Anastomotic leak (AL) remains a significant complication after esophagectomy. Indocyanine green fluorescent angiography (ICG-FA) is a promising and safe technique for assessing gastric conduit (GC) perfusion intraoperatively. It provides detailed visualization of tissue perfusion and has demonstrated usefulness in oesophageal surgery. GC perfusion analysis by ICG-FA is crucial in constructing the conduit and selecting the anastomotic site and enables surgeons to make necessary adjustments during surgery to potentially reduce ALs. However, anastomotic integrity involves multiple factors, and ICG-FA must be combined with optimization of patient and procedural factors to decrease AL rates. This review summarizes ICG-FA's current applications in assessing esophago-gastric anastomosis perfusion, including qualitative and quantitative analysis and different imaging systems. It also explores how fluorescent imaging could decrease ALs and aid clinicians in utilizing ICG-FA to improve esophagectomy outcomes.

Evaluation of indocyanine green tracheobronchial fluorescence (ICG-TBF) via nebulization during minimally invasive esophagectomy

Surgical manipulation of the tracheobronchial complex is a contributing factor in pulmonary morbidity of esophagectomy. Accurate dissection between membranous trachea and bronchi with esophagus is essential. This study tests the feasibility of delivering indocyanine green (ICG) in an aerosol form to achieve tracheobronchial fluorescence (ICG-TBF). Patients with esophageal and esophagogastric junction carcinoma (N = 37) undergoing minimally invasive esophagectomy (McKeown type) were included. ICG was aerosolized by nebulization in supine position before thoracoscopy. ICG-TBF was observed with real-time fluorescence-enabled camera. Intra- and postoperative complications related to ICG were the primary focus. ICG-TBF was identified in 94.6% (35/37) of patients with median time to fluorescence identification of 15 minutes (range 1-43). There were no airway injuries in the study. The ICU median stay was 2 (range 2-21) days. No intra- or postoperative complications attributable to ICG were observed. Grade 3 or 4 pulmonary complications were seen in total 8.1% patients. No 90-day postoperative mortality was seen. ICG delivered in aerosol form was found to be safe and effective in achieving ICG-TBF. It aided in accurate dissection of esophagus from the tracheobronchial complex. Further studies on effect of ICG-TBF in decreasing pulmonary complications of esophagectomy are needed.

Global Cancer Surgery: pragmatic solutions to improve cancer surgery outcomes worldwide

The first Lancet Oncology Commission on Global Cancer Surgery was published in 2015 and serves as a landmark paper in the field of cancer surgery. The Commission highlighted the burden of cancer and the importance of cancer surgery, while documenting the many inadequacies in the ability to deliver safe, timely, and affordable cancer surgical care. This Commission builds on the first Commission by focusing on solutions and actions to improve access to cancer surgery globally, developed by drawing upon the expertise from cancer surgery leaders across the world. We present solution frameworks in nine domains that can improve access to cancer surgery. These nine domains were refined to identify solutions specific to the six WHO regions. On the basis of these solutions, we developed eight actions to propel essential improvements in the global capacity for cancer surgery. Our initiatives are broad in scope, pragmatic, affordable, and contextually applicable, and aimed at cancer surgeons as well as leaders, administrators, elected officials, and health policy advocates. We envision that the solutions and actions contained within the Commission will address inequities and promote safe, timely, and affordable cancer surgery for every patient, regardless of their socioeconomic status or geographic location.

Impact of fluorescent thoracic duct lymphography via intranodal approach in minimal access esophageal cancer surgery

PURPOSE

Chyle leak resulting from thoracic duct (TD) injury poses significant morbidity and mortality challenges. We assessed the feasibility of using near-infrared (NIR) indocyanine green (ICG) imaging for intraoperative fluorescence TD lymphography during minimal access esophagectomy (MAE) in a semiprone position with inguinal nodal injection of ICG dye.

METHODS

Ninety-nine patients with esophageal or gastroesophageal junctional cancer undergoing MAE received inguinal node injections of 2.5 mg ICG dye (total 5 mg) under sonographic guidance during anesthesia induction. Stryker's 1688 AIM HD system was used in 76 cases, Karl Storz OPAL 1 S in 20, and in three cases the Karl Storz Rubina.

RESULTS

In 93 patients (94%), the TD was clearly delineated along its entire length; it was not visualized in 6 patients (6%). Fluorescence guidance facilitated TD ligation in 16 cases, while 3 cases required clipping of duct tributaries for oncological considerations. Twenty-eight patients exhibited minor duct variations. Fluorescence was sustained throughout surgery (median observation time 60 min post-injection; range 30-330). No patient experienced any chyle leak within 30 days post-surgery and no adverse reactions to ICG was evident.

CONCLUSIONS

Intraoperative fluorescence TD lymphography using ICG during MAE in a semiprone position with inguinal nodal injection proved safe, feasible, and effective, allowing clear visualization of the TD in almost all cases. This approach aids safe ligation and reduces chyle leak risk. It offers real-time imaging of TD anatomy and variations, providing valuable feedback to surgeons for managing TD injuries during MAE procedures and represents an excellent educational tool.

Enhancing intraoperative tumor delineation with multispectral short-wave infrared fluorescence imaging and machine learning

SIGNIFICANCE

Fluorescence-guided surgery (FGS) provides specific real-time visualization of tumors, but intensity-based measurement of fluorescence is prone to errors. Multispectral imaging (MSI) in the short-wave infrared (SWIR) has the potential to improve tumor delineation by enabling machine-learning classification of pixels based on their spectral characteristics.

AIM

Determine whether MSI can be applied to FGS and combined with machine learning to provide a robust method for tumor visualization.

APPROACH

A multispectral SWIR fluorescence imaging device capable of collecting data from six spectral filters was constructed and deployed on neuroblastoma (NB) subcutaneous xenografts ( n = 6 ) after the injection of a NB-specific NIR-I fluorescent probe (Dinutuximab-IRDye800). We constructed image cubes representing fluorescence collected from ∼ 850 to 1450 nm and compared the performance of seven learning-based methods for pixel-by-pixel classification, including linear discriminant analysis, k -nearest neighbor classification, and a neural network.

RESULTS

The spectra of tumor and non-tumor tissue were subtly different and conserved between individuals. In classification, a combine principal component analysis and k -nearest-neighbor approach with area under curve normalization performed best, achieving 97.5% per-pixel classification accuracy (97.1%, 93.5%, and 99.2% for tumor, non-tumor tissue and background, respectively).

CONCLUSIONS

The development of dozens of new imaging agents provides a timely opportunity for multispectral SWIR imaging to revolutionize next-generation FGS.

Indocyanine Green (ICG) and Colorectal Surgery: A Literature Review on Qualitative and Quantitative Methods of Usage

Background: Due to its many benefits, indocyanine green (ICG) has gained progressive popularity in operating rooms (ORs) globally. This literature review examines its qualitative and quantitative usage in surgical treatment. Method: Relevant terms were searched in five international databases (1. Pubmed, 2. Sciencedirect, 3. Scopus, 4. Oxfordjournals, 5. Reaxys) for a comprehensive literature review. The main benefits of using ICG in colorectal surgery are: intraoperative fluorescence angiography; fluorescence-guided lymph node involvement detection and the sentinel technique; the fluorescent emphasis of a minute liver tumour, counting just 200 tumour cells; facilitation of fistula diagnosis; and tumour tattooing. This methodology can also be used with quantitative characteristics such as maximum intensity, relative maximum intensity, and in-flow parameters such as time-to-peak, slope, and t1/2max. This article concludes that fluorescence surgery with ICG and near-infrared (NIR) light is a relatively new technology that improves anatomical and functional information, allowing more comprehensive and safer tumour removal and the preservation of important structures.

The magic mirror: a novel intraoperative monitoring method for parathyroid glands

The accurate detection of parathyroid glands (PGs) during surgery is of great significance in thyroidectomy and parathyroidectomy, which protects the function of normal PGs to prevent postoperative hypoparathyroidism and the thorough removal of parathyroid lesions. Existing conventional imaging techniques have certain limitations in the real-time exploration of PGs. In recent years, a new, real-time, and non-invasive imaging system known as the near-infrared autofluorescence (NIRAF) imaging system has been developed to detect PGs. Several studies have confirmed that this system has a high parathyroid recognition rate and can reduce the occurrence of transient hypoparathyroidism after surgery. The NIRAF imaging system, like a magic mirror, can monitor the PGs during surgery in real time, thus providing great support for surgeries. In addition, the NIRAF imaging system can evaluate the blood supply of PGs by utilizing indocyanine green (ICG) to guide surgical strategies. The NIRAF imaging system and ICG complement each other to protect normal parathyroid function and reduce postoperative complications. This article reviews the effectiveness of the NIRAF imaging system in thyroidectomies and parathyroidectomies and briefly discusses some existing problems and prospects for the future.

Fluorescence-guided surgery: National trends in adoption and application in pediatric surgery

BACKGROUND

Fluorescence-guided surgery (FGS) with indocyanine green (ICG) is a rapidly diffusing surgical innovation, but its utilization in pediatrics remains unknown. We present a cross-sectional descriptive analysis of trends from a national database.

METHODS

The Pediatric Health Information System (PHIS) database was queried for patient encounters between January 2016 and July 2021 with an associated ICG administration within 3 days prior to surgery. All procedure codes from each encounter were reviewed by two surgeons to determine the most likely associated FGS procedure and assign an operative category.

RESULTS

1270 encounters were identified from 38 participating hospitals. The mean patient age (SD) was 8.3 (6.4) years, 54.5% were male, 63.8% were white, and 30.1% were Hispanic. The most common categories for ICG use were neurosurgery (21.3%), biliary (18.3%), perfusion (14.8%), urology (12.5%), gastrointestinal (10.8%), ophthalmology (8.8%), and thoracic (5.6%). Utilization over time increased for some categories (thoracic, visceral perfusion, and neurological procedures) or remained stable for other categories. Overall ICG utilization has increased in 2020 (n = 314) compared to 2016 (N = 83). The number of centers utilizing ICG has also increased from 14 hospitals in 2016 to 29 hospitals in 2020 though adoption remains unevenly distributed, with 5 high-utilization hospitals accounting for 56.8% of all ICG FGS cases.

CONCLUSION

ICG is being used across a wide variety of pediatric surgical disciplines. Trends over time show increasingly frequent adoption across the country, with a few high-volume centers driving the innovation. Fluorescence-guided surgery is commercially available and is becoming more commonplace for pediatric surgeons. Dedicated efforts will now be needed to assess outcomes using this promising technology.

LEVEL OF EVIDENCE

Level IV.

STUDY TYPE

Retrospective study.

The location of metastatic lymph nodes and the evaluation of lymphadenectomy by near-infrared photoacoustic imaging with iridium complex nanoparticles

Histopathology evaluation and lymphadenectomy of node-positive patients is the usual procedure in clinical therapy. However, it requires days for the histopathology result analysis, which impedes intraoperative decision-making and immediate treatment. Noninvasive real-time imaging of metastatic lymph nodes can overcome these defects and help medical workers evaluate lymph nodes and make the operation decision more efficiently. Herein we developed iridium(III)-cyanine complex/bovine serum albumin (BSA)-based nanoparticles which are conjugated with folic acid (FA) (IrCy-FA NPs). The synthesized IrCy-FA NPs exhibit good biocompatibility, strong near-infrared absorption, and impressive lymph node accumulation and can serve as a photoacoustic (PA) imaging probe for lymph node imaging. Besides, the lymph nodes enriched with IrCy-FA NPs showing green color are easily visible to the naked eye, suggesting their potential as an intraoperative indicator. The real-time PA imaging with excellent contrast and high spatial resolution can promote efficient and reliable quantitative analysis of lymph nodes in vivo. By employing IrCy-FA NPs as the PA agent for lymph node imaging, we achieve effective pre-operative and post-operative evaluations of metastatic lymph nodes in lymphadenectomy. This study may provide helpful information for PA imaging guided colocalization and evaluation of lymph nodes and facilitate this method towards clinical trials.

Adrenal Near-Infrared Autofluorescence

Context

Parathyroid tissue is one of the few tissues to have strong near-infrared (NIR) autofluorescence, which has been exploited to improve intraoperative parathyroid identification. The US Food and Drug Administration has approved 2 devices for this purpose. Adrenal glands can be difficult to distinguish from surrounding fat, an issue during total adrenalectomy.

Objective

We hypothesized adrenal tissue may also possess considerable NIR autofluorescence.

Methods

Resected patient adrenal specimens were examined after robotic adrenalectomy with an NIR camera intraoperatively. Patients did not receive fluorescent dye. Images were taken of both gross and sectioned specimens. Post hoc image analysis was performed with ImageJ software. Confocal microscopy was performed on selected tissues using immunofluorescence and hematoxylin-eosin staining.

Results

Resected tissue was examined from 22 patients undergoing surgery for pheochromocytomas (6), primary aldosteronism (3), adrenocorticotropin-independent hypercortisolism (10), and a growing or suspicious mass (3). Normal adrenal tissue demonstrated strong NIR autofluorescence. The intensity ratio compared to background (set as 1) for gross images was 2.03 ± 0.51 (P < .0001) compared to adjacent adipose of 1.24 ± 0.18. Autofluorescence from adrenal tumors was also detected at variable levels of intensity. Cortisol-producing tumors had the highest fluorescence ratio of 3.01 ± 0.41. Confocal imaging localized autofluorescence to the cytosol, with the highest intensity in the zona reticularis followed by the zona fasciculata.

Conclusion

Normal and abnormal adrenal tissues possess natural NIR autofluorescence. Highest autofluorescence levels were associated with cortisol-producing tumors. Confocal imaging demonstrated the highest intensity in the zona reticularis. NIR cameras may have the potential to improve identification of adrenal tissue during surgery.

Fluorescence-guided lung nodule identification during minimally invasive lung resections

In the last few years, minimally invasive surgery has become the standard routine practice to manage lung nodules. Particularly in the case of robotic thoracic surgery, the identification of the lung nodules that do not surface on the visceral pleura could be challenging. Therefore, together with the evolution of surgical instruments to provide the best option in terms of invasiveness, lung nodule localization techniques should be improved to achieve the best outcomes in terms of safety and sensibility. In this review, we aim to overview all principal techniques used to detect the lung nodules that do not present the visceral pleura retraction. We investigate the accuracy of fluorescence guided thoracic surgery in nodule detection and the differences among the most common tracers used.

Percutaneous Microcoil Localization of a Small, Totally Endophytic Renal Mass for Nephron-Sparing Surgery: A Case Report and Literature Review

Small, totally endophytic renal masses present a technical challenge for surgical extirpation due to poor identifiability during surgery. The method for the precise localization of totally endophytic tumours before nephron-sparing surgery could be optimized. An asymptomatic 70-year-old male presented with a right-sided, 16-mm, totally endophytic renal mass on computed tomography (CT). CT-guided percutaneous microcoil localization was carried out prior to laparoscopy to provide a direction for partial nephrectomy. During the 25 minutes of the localization procedure, the patient underwent five local CT scans, and his cumulative effective radiation dosage was 5.1 mSv. The span between localization and the start of the operation was 15 hours. The laparoscopic operation time was 105 minutes, and the ischaemia time was 25 minutes. The postoperative recovery was smooth, and no perioperative complications occurred. Pathology showed the mass to be renal clear cell carcinoma, WHO/ISUP grade 2, with a 2-mm, clear surgical margin. The patient remained free of recurrence on follow-up for eleven months. To our knowledge, this application of microcoil implantation prior to laparoscopic partial nephrectomy towards an intrarenal mass could be an early reported attempt for the localized method applied in renal surgery. The percutaneous microcoil localization of endophytic renal tumours is potentially safe and effective prior to laparoscopic partial nephrectomy.

A Series of PSMA-Targeted Near-Infrared Fluorescent Imaging Agents

We have synthesized a series of 10 new, PSMA-targeted, near-infrared imaging agents intended for use in vivo for fluorescence-guided surgery (FGS). Compounds were synthesized from the commercially available amine-reactive active NHS ester of DyLight800. We altered the linker between the PSMA-targeting urea moiety and the fluorophore with a view to improve the pharmacokinetics. Chemical yields for the conjugates ranged from 51% to 86%. The K_i values ranged from 0.10 to 2.19 nM. Inclusion of an N-bromobenzyl substituent at the ε-amino group of lysine enhanced PSMA⁺ PIP tumor uptake, as did hydrophilic substituents within the linker. The presence of a polyethylene glycol chain within the linker markedly decreased renal uptake. In particular, DyLight800-10 demonstrated high specific uptake relative to background signal within kidney, confirmed by immunohistochemistry. These compounds may be useful for FGS in prostate, renal or other PSMA-expressing cancers.

Protein-Based Nanoparticles for the Imaging and Treatment of Solid Tumors: The Case of Ferritin Nanocages, a Narrative Review

Protein nanocages have been studied extensively, due to their unique architecture, exceptional biocompatibility and highly customization capabilities. In particular, ferritin nanocages (FNs) have been employed for the delivery of a vast array of molecules, ranging from chemotherapeutics to imaging agents, among others. One of the main favorable characteristics of FNs is their intrinsic targeting efficiency toward the Transferrin Receptor 1, which is overexpressed in many tumors. Furthermore, genetic manipulation can be employed to introduce novel variants that are able to improve the loading capacity, targeting capabilities and bio-availability of this versatile drug delivery system. In this review, we discuss the main characteristics of FN and the most recent applications of this promising nanotechnology in the field of oncology with a particular emphasis on the imaging and treatment of solid tumors.

Methods of identification of parathyroid glands in thyroid surgery: A literature review

Intra-operative identification and preservation of parathyroid glands is an important but challenging aspect of thyroid surgery. Failure to do so may lead to transient or permanent hypocalcaemia, where the latter represents a serious complication causing life-long morbidity. It would be beneficial, therefore, if a simple and reliable modality can be developed to assist in the identification of parathyroid glands intra-operatively. The aim of this literature review is to provide an overview of intra-operative modalities used to identify parathyroid glands with a particular focus on near-infrared autofluorescence (NIRAF). Twenty-seven studies were considered relevant in this literature review. Several modalities have been used to aid parathyroid gland identification, including Raman spectroscopy, indocyanine green angiography, and NIRAF. NIRAF technology allows parathyroid glands to spontaneously give off light (autofluorescence) when exposed to near-infrared light at a wavelength of 785 nm, creating a contrast between tissues to allow intra-operative differentiation. Studies utilising NIRAF technology were able to identify 76.3%-100% of parathyroid glands intra-operatively. Furthermore, two randomised controlled trials comparing NIRAF and white light showed that the use of NIRAF was able to significantly increase the mean number of parathyroid glands detected and reduce the incidence of post-operative hypocalcaemia. NIRAF is an emerging tool that has been shown to increase the number of intra-operative parathyroid gland identification and reduce the rate of post-operative hypocalcaemia in a safe and reproducible manner. Future trials are needed to evaluate the real-life impact of NIRAF technology in outcomes of patients following thyroid surgery.