Indocyanine green is a sensitive adjunct in the identification and surgical management of local and metastatic hepatoblastoma

Surgical management of liver tumors

Two percent of pediatric malignancies arise primarily in the liver; roughly 60% of these cancers are hepatoblastoma (HB). Despite the rarity of these cases, international collaborative efforts have led to the consistent histological classification and staging systems, which facilitate ongoing clinical trials. Other primary liver malignancies seen in children include hepatocellular carcinoma (HCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), undifferentiated embryonal sarcoma of the liver (UESL), and hepatocellular neoplasm not otherwise specified (HCN-NOS). This review describes principles of surgical management of malignant pediatric primary liver tumors, within the context of comprehensive multidisciplinary care.

Utility of Indocyanine Green for Sentinel Lymph Node Biopsy in Pediatric Sarcoma and Melanoma

BACKGROUND

Indocyanine green (ICG) is a fluorescent dye with increasing use for adult sentinel lymph node biopsy (SLNB). The utility of ICG in pediatric oncology remains understudied. We aim to describe our experience using ICG for SLNB in pediatrics versus standard blue dye.

METHODS

A retrospective review of pediatric patients with melanoma or sarcoma who underwent SLNB with technetium plus ICG or blue dye from 2014 to 2023 at a large academic children's hospital was conducted.

RESULTS

Twenty-four patients were included; 58.3% were male with median age 13 years (range 4-21 years). The majority had a melanocytic tumor (91.7%) and 8.3% had sarcoma. All patients received technetium with concomitant blue dye (62.5%) or ICG (37.5%). ICG more reliably identified radioactive SLNs, compared to blue dye (mean 100% vs 78.3 ± 8.3%, p = 0.03). There was no significant difference in median operative time (ICG 82 min [68-203] vs blue dye 93 min [78-105], p = 0.84). Seven patients had positive SLNs (29.2%), with recurrence in 2 patients (8.3%) and 1 death (4.2%). There were no adverse events.

CONCLUSION

ICG-directed SLNB in children is a safe and effective alternative to blue dye. Use of ICG did not add to operative time, and more often identified sentinel nodes versus blue dye.

TYPE OF STUDY

Original Research Article, Retrospective Comparative Study.

LEVEL OF EVIDENCE

III.

Digital medicine and minimally invasive surgery in pediatric hepatoblastoma: An update

Hepatoblastoma (HB) is the most common liver malignancy in children, accounting for approximately 60 % of liver tumors in this population. However, the exact cause of HB remains unclear. The combination of surgery and neoadjuvant chemotherapy has significantly improved the overall survival rate of children with HB, increasing it from 40 % in the past to over 70 %. The concept of precise hepatectomy, which aims to achieve the best rehabilitation outcomes with minimal trauma and maximum liver protection, has been widely accepted by hepatobiliary surgeons. This article provides a comprehensive review of the recent advancements in surgical treatment of HB, focusing on digital surgery and minimally invasive techniques.

Current trends and prospects of surgical techniques for hepatoblastoma

Hepatoblastoma, a common extracranial malignant solid tumor in childhood, is often detected at an advanced stage and is difficult to treat surgically. Despite the availability of multiple comprehensive treatments that can be combined with surgery, hepatoblastoma treatment outcomes remain poor. Surgery is the main treatment strategy for hepatoblastoma, but it faces many challenges, including tumor attachment to surrounding tissues, tumor wrapping or invading of vital organs and tissues, the presence of giant or multiple tumors, distant metastasis, the formation of a tumor thrombus, and significant surgical trauma. In this review, we discuss recent research advances and propose potential strategies for overcoming these challenges. Such strategies may improve the rate of hepatoblastoma resection and local control in children, as well as reduce complications and trauma.

Fluorescent-guided surgery and the use of indocyanine green sentinel lymph node mapping in the pediatric and young adult oncology population

BACKGROUND

Technetium-99 (99m Tc) lymphoscintigraphy with blue dye injection is an accepted method for sentinel lymph node (SLN) mapping, but blue dye has known adverse effects, and injection of 99m Tc may increase time under anesthesia for pediatric patients. Indocyanine green (ICG) may serve as an adjunct to assist with visibility and identification of SLNs. We hypothesized that sensitivity of ICG was similar to blue dye in SLN biopsies.

METHODS

Thirty patients (36 procedures with 96 total specimens) underwent preoperative intradermal injection of 99m Tc, followed by intradermal injection of isosulfan blue and ICG. Test characteristics of blue dye, ICG, and 99m Tc included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

ICG had a sensitivity of 87% and PPV of 83% for detection of 99m Tc-hot lymph nodes; blue dye had a sensitivity of 44% and PPV of 97%. For detection of pathologically confirmed lymph nodes, ICG had a sensitivity of 84% and a positive predictive value (PPV) of 91%. 99m Tc had a sensitivity of 82% and a PPV of 94%. ICG had no significant difference in odds of being positive in pathology-confirmed lymph nodes compared to 99m Tc (odds ratio [OR], 0.818; 95% confidence interval [CI], 0.3-2.172; p = .823) and had higher odds than isosulfan blue (OR, 0.025, 95% CI, 0.001-0.148; p < .001).

CONCLUSION

This study established the efficacy of ICG as an adjunct to SLNB in the pediatric and young adult population. ICG was safe, more efficacious than blue dye, and may obviate the need for lymphoscintigraphy in selected patients resulting in reduced time under anesthesia.

Evaluating the clinical efficacy and limitations of indocyanine green fluorescence-guided surgery in childhood hepatoblastoma: A retrospective study

BACKGROUND

Indocyanine green (ICG) fluorescence guided surgery has been used to treat childhood hepatoblastoma (HB), but the advantages and disadvantages of this technique have not been fully discussed. The purpose of this study is to summarize the experience and to explore the clinical value of this technique for children with HB.

METHODS

45 children with HB who underwent ICG fluorescence guided surgery (n = 22) and general surgery (n = 23) in our center from January 2020 to December 2022 were enrolled retrospectively.

RESULTS

All the liver tumors in the ICG group showed hyperfluorescence, including total and partial fluorescent types. With the help of ICG navigation, minimally invasive surgery was performed in 3 cases. 18.2 % of cases with tumors could not be accurately identified under white light, but could be identified by fluorescence imaging. The fluorescent cutting lines of 59.1 % of cases were consistent with the safe cutting lines. In 36.4 % of cases, the fluorescence boundary was not clear because of tumor necrosis. In 36.4 % of cases, the fluorescence could not be detected on the inner edge of the tumors because of the depth. A total of 29 ICG (+) suspicious lesions were found during the operations, of which 5 were true positive lesions.

CONCLUSION

ICG fluorescence guided surgery is safe and feasible in children with HB. This technique is helpful for locating tumors, determining margin and finding small lesions with negative imaging, especially in minimally invasive surgery. However, preoperative chemotherapy, tumor necrosis, tumor depth, and ICG administration impact the effect of fluorescence imaging.

Identification of Pediatric Tumors Intraoperatively Using Indocyanine Green (ICG)

BACKGROUND

Fluorescence-guided surgery (FGS) with indocyanine green (ICG) is increasingly applied in pediatric surgical oncology. However, FGS has been mostly reported in case studies of liver or renal tumors. Applying novel technologies in pediatric surgical oncology is more challenging than in adult surgical oncology due to differences in tumor histology, biology, and fewer cases. No consensus exists on ICG-guided FGS for surgically managing pediatric solid tumors. Therefore, we reviewed the literature and discuss the limitations and prospects of FGS.

METHODS

Using PRISMA guidelines, we analyzed articles on ICG-guided FGS for childhood solid tumors. Case reports, opinion articles, and narrative reviews were excluded.

RESULTS

Of the 108 articles analyzed, 17 (14 retrospective and 3 prospective) met the inclusion criteria. Most (70.6%) studies used ICG to identify liver tumors, but the timing and dose of ICG administered varied. Intraoperative outcomes, sensitivity and specificity, were reported in 23.5% of studies. Fluorescence-guided liver resections resulted in negative margins in 90-100% of cases; lung metastasis was detected in 33% of the studies. In otolaryngologic malignancies, positive margins without fluorescence signal were reported in 25% of cases. Overall, ICG appeared effective and safe for lymph node sampling and nephron-sparing procedures.

CONCLUSIONS

Despite promising results from FGS, ICG use varies across the international pediatric surgical oncology community. Underreported intraoperative imaging outcomes and the diversity and rarity of childhood solid tumors hinder conclusive scientific evidence supporting adoption of ICG in pediatric surgical oncology. Further international collaborations are needed to study the applications and limitations of ICG in pediatric surgical oncology.

Feasibility of indocyanine green-guided localization of pulmonary nodules in children with solid tumors

BACKGROUND

Clearing all pulmonary metastases is essential for curing pediatric solid tumors. However, intraoperative localization of such pulmonary nodules can be challenging. Therefore, an intraoperative tool that localizes pulmonary metastases is needed to improve diagnostic and therapeutic resections. Indocyanine green (ICG) real-time fluorescence imaging is used for this purpose in adult solid tumors, but its utility in pediatric solid tumors has not been determined.

METHODS

A single-center, open-label, nonrandomized, prospective clinical trial (NCT04084067) was conducted to assess the ability of ICG to localize pulmonary metastases of pediatric solid tumors. Patients with pulmonary lesions who required resection, either for therapeutic or diagnostic intent, were included. Patients received a 15-minute intravenous infusion of ICG (1.5 mg/kg), and pulmonary metastasectomy was performed the following day. A near-infrared spectroscopy iridium system was optimized to detect ICG, and all procedures were photo-documented and recorded.

RESULTS

ICG-guided pulmonary metastasectomies were performed in 12 patients (median age: 10.5 years). A total of 79 nodules were visualized, 13 of which were not detected by preoperative imaging. Histologic examination confirmed the following histologies: hepatoblastoma (n = 3), osteosarcoma (n = 2), and one each of rhabdomyosarcoma, Ewing sarcoma, inflammatory myofibroblastic tumor, atypical cartilaginous tumor, neuroblastoma, adrenocortical carcinoma, and papillary thyroid carcinoma. ICG guidance failed to localize pulmonary metastases in five (42%) patients who had inflammatory myofibroblastic tumor, atypical cartilaginous tumor, neuroblastoma, adrenocortical carcinoma, or papillary thyroid carcinoma.

CONCLUSIONS

ICG-guided identification of pulmonary nodules is not feasible for all pediatric solid tumors. However, it may localize most metastatic hepatic tumors and high-grade sarcomas in children.

Development of Iodinated Indocyanine Green Analogs as a Strategy for Targeted Therapy of Liver Cancer

Liver cancer is one of the leading causes of cancer-related deaths, with a significant increase in incidence worldwide. Novel therapies are needed to address this unmet clinical need. Indocyanine green (ICG) is a broadly used fluorescence-guided surgery (FGS) agent for liver tumor resection and has significant potential for conversion to a targeted therapy. Here, we report the design, synthesis, and investigation of a series of iodinated ICG analogs (I-ICG), which can be used to develop ICG-based targeted radiopharmaceutical therapy. We applied a CRISPR-based screen to identify the solute carrier transporter, OATP1B3, as a likely mechanism for ICG uptake. Our lead I-ICG compound specifically localizes to tumors in mice bearing liver cancer xenografts. This study introduces the chemistry needed to incorporate iodine onto the ICG scaffold and defines the impact of these modifications on key properties, including targeting liver cancer in vitro and in vivo.

Children's Oncology Group's 2023 blueprint for research: Liver tumors

Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Children's Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.

Retreatment with Cisplatin May Provide a Survival Advantage for Children with Relapsed/Refractory Hepatoblastoma: An Institutional Experience

BACKGROUND

Hepatoblastoma (HB) is the most common liver malignancy in children. There is no standard of care for management of relapsed/refractory HB (rrHB) and reports in the literature are limited.

OBJECTIVE

To describe presenting features, biology, treatment strategies, and outcomes for pediatric patients with relapsed/refractory hepatoblastoma.

METHODS

An IRB-approved retrospective institutional review of patients with rrHB who presented for consultation and/or care from 2000-2019. Clinical, radiographic, and histologic data were collected from all patients.

RESULTS

Thirty subjects were identified with a median age of 19.5 months (range 3-169 months) at initial diagnosis and 32.5 months (range 12-194 months) at time of first relapse. 63% of subjects were male, 70% Caucasian, and 13% were born premature. Three subjects had a known cancer predisposition syndrome. Eight patients had refractory disease while 22 patients had relapsed disease. Average time from initial diagnosis to relapse or progression was 12.5 months. Average alpha-fetoprotein (AFP) at initial diagnosis was 601,203 ng/mL (range 121-2,287,251 ng/mL). Average AFP at relapse was 12,261 ng/mL (range 2.8-201,000 ng/mL). For patients with tumor sequencing (n = 17), the most common mutations were in CTNNB1 (13) and NRF2 (4). First relapse sites were lungs (n = 12), liver (n = 11) and both (n = 6). More than one relapse/progression occurred in 47% of subjects; 6 had ≥3 relapses. Pathology in patients with multiply relapsed disease was less differentiated including descriptions of small cell undifferentiated (n = 3), pleomorphic (n = 1), transitional liver cell tumor (n = 2) and HB with carcinoma features (n = 1). All subjects underwent surgical resection of site of relapsed disease with 7 subjects requiring liver transplantation. Overall survival was 50%. Survival was associated with use of cisplatin at relapse (78.6% with vs. 25% without, p = 0.012). The most common late effect was ototoxicity with at least mild sensorineural hearing loss found in 80% of subjects; 54% required hearing aids.

CONCLUSIONS

Retreatment with cisplatin at the time of relapse may provide an advantage for some patients with hepatoblastoma. Multiply relapsed disease was not uncommon and not associated with a worse prognosis. Careful attention should be paid to cumulative therapy-induced toxicity while concurrently aiming to improve cure.

Effectiveness of indocyanine green fluorescence imaging in resection of hepatoblastoma

OBJECTIVE

The present research aimed to analyze the application of indocyanine green (ICG) fluorescence contrast technique in the resection of hepatoblastoma (HB) in children, and to discuss the use of ICG in the surgery of HB and the value of guidance.

METHODS

We retrospectively analyzed the data of 23 children with HB resected using ICG fluorescence contrast technique at the Children's Hospital of Nanjing Medical University from June 2020 to September 2022, including 16 boys and 7 girls, aged 5 days to 80 months. The patients were administered with an ICG injection of 0.1 mg/kg around 24-48 h before surgery. The surgical margin was detected by real-time fluorescence imaging and confirmed by postoperative pathology.

RESULTS

All primary lesions showed bright fluorescence in 23 HB cases. 22 had clear borders with normal liver tissue, while one neonatal case showed no difference between tumor and background. 13 anatomic resection and 10 non-anatomic resection were performed with ICG fluorescence navigation. The surface of the residual liver was scattered with multiple tumor fluorescence, which was then locally enucleated according to the fluorescence. 22 isolated specimens were dissected and fluorescently visualized. Pathology identified deformed, vacuolated and densely arranged hepatocytes resembling pseudo-envelope changes without tumor residual, due to the compression of the tissue at the site of circumferential imaging.

CONCLUSION

The ring ICG fluorescence imaging of HB indicates the tumor resection boundary effectively, especially in multiple lesions cases.

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.

Recent advances in surgical strategies and liver transplantation for hepatoblastoma

Hepatoblastoma (HB) is the most common malignant liver tumor in children. Although the development of treatment strategies with advances in chemotherapy has greatly improved the prognosis of HB, surgical resection and liver transplantation still play a vital role in the treatment of HB. In recent years, technological innovations have led to the development of new surgical approaches for HB. In this review, we describe the latest research on the surgical management of HB, including new imaging technologies, minimally invasive approaches, and the application of associating liver partition portal vein ligation for staged hepatectomy. We also discuss the current role of liver transplantation, use of ante-situm or ex-situ liver resection with auto-transplantation, and management of metastatic HB.

Indocyanine green navigation in minimally invasive resection of multiple metachronous pulmonary metastases of hepatoblastoma

Pulmonary metastases from hepatoblastoma (HB) have traditionally been identified by preoperative computed tomography scan image evaluation, and intraoperative visual and palpatory examinations through thoracotomy have been generally recommended. However, the safety and accuracy of surgery can be problematic in patients with small multiple lung metastases due to postoperative respiratory dysfunction risk secondary to decreased residual lung capacity in wedge resections. We present an 8-month-old patient with metastatic HB with multiple metachronous pulmonary lesions in whom thoracoscopic lung resections were performed guided by indocyanine green (ICG) administered intravenously 24 h earlier (0.5 mg/kg). ICG fluorescence allowed identification and limited resection of lung parenchyma, avoiding postoperative respiratory dysfunction. A total of 16 lung lesions were resected during four operations (two bilateral and two right thoracoscopies), with no postoperative complications. ICG-guided thoracoscopic surgery allowed identification and resection of metastatic nodules in both lungs during the same procedure, achieving a hospital stay of less than 3 days for each intervention. The patient is currently 24 months old and remains asymptomatic, with no distant disease at the last imaging control. ICG-guided resection via a thoracoscopic approach is particularly useful in patients with multiple and/or metachronous metastases requiring multiple surgical interventions.

Deploying Indocyanine Green Fluorescence-Guided Navigation System in Precise Laparoscopic Resection of Pediatric Hepatoblastoma

Background: Hepatoblastoma (HB) is the most common form of liver cancer in children. To date, complete tumor resection is still the gold standard for treating HB. Indocyanine green (ICG) has been identified as a sensitive adjunct that is highly effective in the identification and surgical management of local and metastatic HB. It has thus becomes an increasingly popular choice among surgeons in HB resection surgeries that are fluorescence-guided. However, laparotomy remains the preferred choice in most cases since the applications and limitations of fluorescence-guided laparoscopic surgery in treating HB remain unclear. In this study, the characteristics and outcomes of laparoscopic HB resections that were guided by intraoperative ICG fluorescent imaging were investigated. Methods: Seven HB patients underwent ICG-guided laparoscopic HB resection surgery from August 2019 to December 2021. ICG was intravenously administered to the patients at a dosage of 0.5 mg/kg 48 h prior to the scheduled operation. During operation, tumor localization and resection boundary were guided by fluorescence visualization. The data on surgical and clinical features were collected retrospectively. Results: The resection area and tumor boundary could be clearly viewed in real-time under the ICG fluorescence imaging navigation system during operation, except for one patient who had received interventional chemoembolization before surgery. The image produced by laparoscopic fluorescence navigation was clear since it was not affected by ambient light. All tumors were completely resected as confirmed by negative margins for HB during postoperative pathological examination. No residual or recurrence were also found through computed tomography during follow-up visits from 9 to 37 months. Conclusions: ICG fluorescence-guided laparoscopic surgery is safe and effective in treating HB due to its ability to provide clear information on tumor localization and delineate tumor margins in real-time.

Clinicopathological study of surgery for pulmonary metastases of hepatoblastoma with indocyanine green fluorescent imaging

BACKGROUND

The prognosis of metastatic hepatoblastoma remains poor; to improve it, pulmonary metastasis must be controlled. Indocyanine green (ICG) fluorescent imaging has been used recently for lung metastasectomy. The objective of our study was to clarify the usefulness of ICG imaging for lung metastasectomy of hepatoblastoma using detailed clinicopathological analysis.

PROCEDURE

Patients with hepatoblastoma who underwent resection of pulmonary metastases with ICG fluorescent imaging were studied using a retrospective analysis of clinical information, a review of their surgical records, and a histological analysis of their metastatic nodules.

RESULTS

Sixteen patients were enrolled. In total, 61 ICG imaging-guided pulmonary metastasectomies were performed, and 350 ICG-positive and 23 ICG-negative specimens were identified. Tumors were confirmed in 250 of the ICG-positive specimens, including eight nonpalpable nodules, on microscopic examination. ICG-positive and tumor-negative specimens showed histological changes suggesting the regression of a tumor or bloodstream disturbance.

CONCLUSIONS

Surgical resection is one of the few treatment strategies available to patients with hepatoblastoma with multiple relapses of pulmonary metastasis resistant to chemotherapy. This study demonstrates the high sensitivity of ICG imaging and that thorough metastasectomy can be achieved with ICG imaging. Because a number of false-positive specimens were detected, further optimization of the dose of ICG and the timing of its administration, and establishment of detection of ICG-positive, tumor-negative nodules during surgery are important issues. Several false-negative specimens were also detected, suggesting the presence of ICG-negative metastatic tumors. Palpation during surgery and imaging studies remain essential for detecting metastatic lesions, even in the era of ICG imaging.

Tumor-Background Ratio is an effective method to identify tumors and false-positive nodules in indocyanine-green navigation surgery for pediatric liver cancer

BACKGROUND

Indocyanine green (ICG) navigation surgery has been used for hepatoblastoma (HB) in children but the technique has been reported for using in other childhood liver cancers were rare. This article summarizes the application experience of ICG in HB and other childhood liver cancers in children and explores the role of fluorescence intensity measurement in identifying tumors.

METHODS

To summarize the clinical experience of children with liver cancer treated by ICG navigation surgery. The tumor and its surrounding tissue were photographed by near infrared during the operation. The fluorescence intensity of tumors, ICG (+) lesions and the normal liver was measured, and the Tumor-Background Ratio (TBR) was calculated.

RESULTS

A total of 11 children with liver cancer were injected intravenously with ICG 1 day before operation. With the help of ICG fluorescence navigation, there was no residual tumor at the surgical margin for all the children. Total fluorescence was seen in 2 cases, rim fluorescence in 2 cases, and partial fluorescence in 7 cases. 19 ICG false-positive nodules were found on the resection stump or residual liver tissue in 5 cases, and the TBR value of tumors was higher than that of false- positive nodules. 10 children have survived without disease.

CONCLUSION

ICG navigation surgery is safe and feasible for liver cancer in children, which can enhance the visualization of the tumor during operation and provide more information about the location and boundaries of the tumor. This technique also has limitations, which can be affected by chemotherapy, tumor location, ICG administration regimen, and equipment. TBR is an effective method to identify tumor and non-cancerous lesions.