Indocyanine green fluorescence imaging for resection of pulmonary metastasis of hepatocellular carcinoma

Background: Indocyanine green (ICG) accumulates in hepatocellular carcinoma (HCC), and tumor fluorescence can be observed under irradiation with near infrared light (NIR). This study investigated the clinical utility of ICG fluorescence imaging during resection of pulmonary metastases of HCC.
Methods: From April 2010 to June 2018, six patients with suspected pulmonary metastasis of HCC were enrolled prospectively. Prior to surgery, all patients underwent the ICG hepatic function test following intravenous administration of ICG (0.5 mg/kg body weight). During surgery, metastatic HCC was identified by observation of ICG fluorescence, allowing assessment of the surgical margin. Tumor fluorescence was also evaluated on cut sections.
Results: A total of 11 metastatic HCCs were resected in six patients at nine operations. Eight lesions were removed by wedge resection and 3 lesions were managed by lobectomy. During surgery, tumor fluorescence could be confirmed through the visceral pleura in 6 out of 7 lesions treated by wedge resection, while NIR irradiation was difficult for 1 lesion. For these 6 lesions, the median distance from the tumor to the visceral pleura and the median surgical margin were 0 mm (range, 0–2 mm) and 14 mm (range, 11–17 mm), respectively. When cut sections were examined, all tumors emitted fluorescence. All lesions were histologically confirmed to be metastatic HCC.
Conclusions: In patients with pulmonary metastasis of HCC, ICG fluorescence imaging is useful for identifying the tumor and securing its margin when the lesion is peripheral and wedge resection is planned.

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