Identification Of Occult Liver Metastases

Background/Aim: Assessment of hepatic metastases is of major importance in the treatment of digestive tract cancers. Even with advanced clinical imaging modalities, extremely small hepatic micrometastases may be overlooked, and those occult metastases may play critical roles in early-term cancer relapse after surgery. To identify hepatic micrometastases not detected by conventional methods, we employed indocyanine green (ICG) fluorescence imaging in real time during hepatobiliary and pancreatic cancer surgery. Patients/Methods: In this study, 125 consecutive patients were examined. Out of 125 patients, 99 had pancreatobiliary cancer and no evident hepatic tumors were apparent on clinical imaging, and 26 had colorectal cancer with overt hepatic metastases which were scheduled for excision. ICG was injected intravenously the day before surgery, and the liver was observed using a near-infrared camera system with laparotomy. The abnormal hepatic fluorescent foci were biopsied. Frozen tissue sections were examined histologically. Results: No adverse events related to the examination were evident. Hepatic micrometastases were confirmed in 17 patients (14%): 13 with pancreatobiliary cancer and 4 with colorectal cancer (in addition to their preoperatively overt metastases). The pancreatobiliary cancer patients with hepatic micrometastases were judged as having unresectable disease and underwent only palliative surgery. In the 4 patients with hepatic micrometastases from colorectal cancer, resection was intended to eradicate all of the metastases. Regardless of cancer origin, the patients with hepatic micrometastases received adjuvant systemic chemotherapy. Follow-up imaging studies within 12 months of surgery showed more frequent overt hepatic metastases in patients with micrometastases (13/14:93%) than in those without (12/100:12%; p = 0.000). Conclusions: ICG fluorescence imaging is useful for detection of hepatic micrometastases from digestive cancers and contributes to precise cancer staging. Hepatic micrometastases detected by this method had adverse clinical impacts which herald early-term hepatic relapse after surgery. Copyright (C) 2013 S. Karger AG, Basel