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

Why This Technique Matters

Complete surgical resection remains the cornerstone of hepatoblastoma treatment, but the fundamental challenge is deceptively simple: you cannot resect what you cannot see 0:27. Standard intraoperative assessment—direct visualization, palpation, and preoperative imaging correlation—misses tumor deposits with enough frequency that surgeons have sought adjunctive detection methods 0:27. Indocyanine green (ICG) fluorescence imaging emerged as one such tool, borrowed from hepatobiliary surgery and adapted to pediatric oncology 0:12. The question driving this work is equally straightforward: are you actually seeing all the hepatoblastoma during your resection? 0:27

The Core Problem

Hepatoblastoma presents in two surgical contexts: primary liver tumors requiring hepatic resection and pulmonary metastases requiring metastatectomy 0:12. In both settings, incomplete resection directly predicts recurrence 0:27. The difficulty is that tumor deposits small enough to evade preoperative CT or MRI may also escape intraoperative detection 0:27, particularly in chemotherapy-treated tissue where inflammation and fibrosis obscure tissue planes. Relapsed disease compounds this problem—surgeons operate in previously violated fields where normal anatomic landmarks are distorted 0:50.

How ICG Fluorescence Works in This Context

ICG is administered before surgery and preferentially accumulates in hepatoblastoma tissue 0:12. Under near-infrared imaging, tumor deposits fluoresce, creating contrast against normal parenchyma 0:12. The technique adapts to both open and minimally invasive approaches 0:50.

This single-institution retrospective review examined patients who received ICG before either liver resection or pulmonary metastatectomy for hepatoblastoma 0:12. The method proved highly sensitive—approximately 90%—for detecting tumor 0:22. More clinically significant: in a meaningful number of cases, ICG identified deposits that were not visible, palpable, or detectable on preoperative imaging 0:27. These are lesions that would have been left behind under standard technique 0:27.

The specificity was lower than the sensitivity, generating false positives 0:39. These false signals often represented vascular changes or inflammation rather than tumor 0:43. This is the expected trade-off when increasing detection sensitivity: you accept some false alarms to avoid missing true disease 0:39. Critically, there were no adverse outcomes associated with any of the additional resections guided by ICG 0:46. The cost of resecting a false positive—removing a small margin of inflamed or vascular tissue—proved negligible compared to the cost of leaving residual tumor 0:46.

Where Practice Remains Uncertain

The study does not define what constitutes a "meaningful number" of occult lesions detected, nor does it quantify how many patients had their surgical plan altered by ICG findings 0:27. The false positive rate is acknowledged but not precisely reported 0:39, leaving referring clinicians without a clear sense of how often ICG signals require resection of benign tissue. The discussion also does not address whether ICG detection of additional disease changed long-term outcomes—whether finding these occult deposits actually improved survival or reduced recurrence rates. That question requires longer follow-up and likely a multi-institutional cohort.

What is clear: ICG worked across disease contexts. It was effective in both primary and relapsed hepatoblastoma 0:50, suggesting the technique retains utility even in surgically hostile, previously treated fields 0:50. It functioned in both open and minimally invasive surgery 0:50, meaning the technology does not constrain surgical approach 0:50.

When to Consider This Approach

For surgeons planning hepatoblastoma resection—either primary hepatic tumor or pulmonary metastases—ICG fluorescence imaging offers a low-risk adjunct with demonstrated ability to detect occult disease 0:27. The technique appears most valuable when operating in contexts where standard assessment is least reliable: chemotherapy-treated tissue, relapsed disease, or minimally invasive approaches where palpation is limited or absent 0:27 0:50 0:50.

For referring oncologists, the relevant question is whether the surgical team has access to ICG imaging capability and experience interpreting fluorescence signals in pediatric oncology 0:12. The technology is not universal, and effective use requires distinguishing true tumor fluorescence from false positive signals 0:39 0:43. The finding that additional ICG-guided resections caused no adverse outcomes 0:46 suggests the threshold for resecting a fluorescent focus can be reasonably low—the penalty for removing benign tissue is small, while the penalty for leaving tumor is large 0:46.

The central value proposition is increased confidence in complete resection 0:27. In a disease where surgical margins determine outcome 0:27, a tool that reveals otherwise invisible tumor deposits addresses a fundamental limitation of human perception 0:27. Whether that translates to improved survival remains to be demonstrated, but the logic is sound: you cannot cure what you cannot remove, and you cannot remove what you cannot find 0:27.

Why Fluorescence Imaging Exists in Pediatric Oncologic Surgery

Complete resection determines survival in hepatoblastoma 0:12. The surgeon's task is binary: remove all viable tumor or accept that the child will relapse. Standard intraoperative assessment — direct visualization, palpation, and preoperative cross-sectional imaging — misses occult deposits often enough that adjuncts matter 0:27. Indocyanine green fluorescence imaging emerged to address this gap. ICG, a near-infrared fluorophore cleared by hepatocytes, accumulates in hepatoblastoma and fluoresces under appropriate illumination, rendering tumor deposits visible that would otherwise be invisible to the eye and hand 0:22 0:27.

The Core Problem

Hepatoblastoma presents in two surgical contexts: primary liver resection after neoadjuvant chemotherapy, and pulmonary metastatectomy for distant disease 0:12. In both settings, the question is the same: are you seeing all the tumor? 0:12 Preoperative imaging has known resolution limits 0:27. Intraoperative assessment is constrained by what the surgeon can see on the surface and feel beneath it 0:27. Small deposits — particularly in chemotherapy-altered tissue or in the lung parenchyma — are easy to miss. A missed deposit is a failed operation.

How ICG Fluorescence Works in This Context

ICG is administered intravenously prior to resection 0:22. The dye is taken up by hepatocytes and retained in hepatoblastoma cells, likely due to altered biliary excretion in malignant tissue 0:22. Under near-infrared illumination, tumor deposits fluoresce, appearing bright against the background of normal liver or lung 0:22. The surgeon uses this real-time visual feedback to guide resection margins and to search for additional lesions 0:22 0:27.

In the Cincinnati series, ICG demonstrated approximately 90% sensitivity for detecting hepatoblastoma 0:22. More importantly, in a meaningful number of cases, ICG identified tumor deposits that were not visible, palpable, or evident on preoperative imaging 0:27. These are lesions that would have been left behind using conventional technique alone 0:27. The clinical implication is straightforward: fluorescence guidance changes the operation by revealing disease that standard assessment misses 0:27.

Specificity was lower than sensitivity, with false positives occurring 0:39. These false signals often represented vascular changes or inflammation rather than tumor 0:43. This is the expected trade-off with a sensitive adjunct: you resect some benign tissue to avoid missing malignant tissue. Notably, there were no adverse outcomes associated with any of the additional resections guided by ICG 0:46. The cost of a false positive in this context is minimal — slightly more tissue removed, no added morbidity — while the cost of a false negative is recurrence.

Where Practice Remains Uncertain

The data presented are from a single institution retrospective review 0:12. The sensitivity figure is promising but not definitive 0:22. What remains unclear is how often ICG-detected lesions, had they been left in place, would have led to clinically significant recurrence versus representing chemotherapy effect or necrotic tissue that would not have progressed. The false positive rate matters less if every additional resection is harmless 0:46, but in marginal cases — where taking more tissue compromises function or where the lung parenchyma is already limited — the distinction between true and false signal becomes clinically relevant. The discussion does not address how to adjudicate an ICG-positive, pathology-negative finding intraoperatively, nor does it provide guidance on when to stop resecting fluorescent tissue.

Another open question: does ICG change survival, or does it change only the surgeon's confidence? The study reports no adverse outcomes from additional resections 0:46, but it does not report recurrence rates or compare outcomes to a non-ICG cohort. The value proposition is intuitive — finding more tumor should improve outcomes 0:27 — but the data here do not close that loop.

When to Use This Technique

ICG was effective in both open and minimally invasive approaches, and in both primary and relapsed disease 0:50 0:50. This suggests broad applicability across the spectrum of hepatoblastoma surgery 0:50 0:50. The technique does not require specialized equipment beyond near-infrared imaging capability, which is increasingly standard in operating rooms performing oncologic or hepatobiliary cases.

For the referring oncologist or general pediatric surgeon, the relevant threshold is this: if you are resecting hepatoblastoma — whether primary liver tumor or pulmonary metastasis — and you have access to ICG fluorescence imaging, use it [q2]. The sensitivity is high enough and the false positive cost low enough that the adjunct is justified 0:22 0:46. If you do not have access, the discussion suggests this is a capability worth acquiring, particularly in centers that manage hepatoblastoma with any regularity 0:22 0:27. The question is not whether ICG will detect additional disease — the data say it will 0:27 — but whether your practice can incorporate the additional information without overreacting to false signals 0:39 0:43. That is a judgment that comes with experience, not with the technology itself.