Page 61 - Fluorescence-guided cancer surgery

Laparoscopic imaging of hepatic uveal melanoma metastases 59
INTRODUCTION
Uveal melanoma is the most common primary intraocular tumor in adults and up to 50% of patients will ultimately develop distant metastases1. In 90-95% of these patients, the metastases will involve the liver2;3. Complete resection of these metastases can prolong survival, however only few patients are eligible for radical surgical treatment4-6. Therefore, it is of great importance to select and treat these patients carefully, to prevent unnecessary laparotomies and to fully resect sites of metastasis. Minimally invasive procedures have become important in daily clinical practice, are increasingly used for liver surgery, and might help to optimize the resection of malignant disease.
Near-infrared (NIR) uorescence imaging using indocyanine green (ICG) is a promising technique to assist in the intraoperative identi cation of liver metastases in real time7-10. ICG is excreted exclusively into the bile after intravenous injection and it has been hypothesized that colorectal liver metastases can be visualized due to passive accumulation of ICG caused by hampered biliary excretion, which results in a uorescent rim around metastases7;11.
Several clinical studies describe the use of NIR uorescence imaging to visualise primary hepatocellular carcinomas8, as well as liver metastases from colorectal12, and pancreatic cancers9 after intravenous injection of ICG, 1 to 14 days prior to surgery. The dose and interval between ICG administration and surgery are key determinants of the remaining background uorescence signal in the liver and the uorescent rim surrounding the tumor. A dose nding study using an open intraoperative imaging system (Mini-FLARE13) in patients with colorectal liver metastases was recently performed in our center12, and 10 mg ICG administered 24 h before surgery was found to be the most favorable dosage and time point of ICG administration. Moreover, in 12.5% of patients additional small and super cially located lesions were detected using NIR uorescence, which were otherwise undetectable.
Published cases to date for intraoperative detection of liver metastases using NIR uorescence and ICG were performed as open procedures. A laparoscopic operation is preferable for patients with liver metastases from uveal melanoma, due to the high risk of multiple small metastases. When multiple metastases are identi ed during surgery, patients would not bene t from liver resection, and can be saved an unnecessary laparotomy by performing this minimally