Detection of Hepatic Micrometastases from Pancreatic Cancer

Abstract

The detection of hepatic metastases is critical in the treatment of pancreatic cancer, because their presence suggests systemic disease with poor prognosis. Although recent advances in high-resolution imaging have allowed physicians to delineate small hepatic tumors, some of those might still be missed owing to their location and miniscule size. Such micrometastases may result in early-term hepatic relapse after radical surgery for pancreatic cancer. We utilize indocyanine green (ICG) near-infrared (NIR) fluorescence imaging which better detects extremely small hepatic lesions to identify hepatic micrometastases intraoperatively. Our experience demonstrates that ICG-NIR imaging successfully detects hepatic micrometastases in approximately one sixth of pancreatic cancer patients without suspicion of hepatic disease before surgery. The hepatic micrometastases detected microscopically originate from the tumor thrombi at the intrahepatic portal triad, and their local invasion results in focal obstructive jaundice that might fluoresce under ICG-NIR. Patients with hepatic micrometastases frequently experience overt hepatic relapse within 6 months after surgery; therefore, such hepatic micrometastases seem to be clinically evident as distant metastases. ICG-NIR fluorescence examination contributes to real-time cancer staging and the elucidation of pancreatic cancer biology.