Utility of F-18-FDG positron emission tomography scanning on selection of patients for resection of hepatic colorectal metastases

BACKGROUND: Hepatectomy represents a standard and potentially curative ther apy for hepatic colorectal metastases. However, up to two thirds of patient s explored for resection are found to have unsuspected disease, which precl udes resection. METHODS: In order to determine if F-18-FDG positron emission tomography (PE T) scanning may prevent unnecessary surgery, a group of 40 patients being c onsidered for hepatic resection but at high risk for unresectable disease b y clinical criteria were subjected to whole body F-18- FDG-PET scanning. Ef fect on clinical outcome was evaluated. In addition, PET findings in the 25 patients who undennrent resection of hepatic metastases were directly comp ared with the resected specimen to determine the sensitivity of F-18-FDG PE T scanning in the liver. RESULTS: Findings on F-18-FDG-PET scanning influenced the clinical manageme nt in 16 patients (40%) and directly altered management in 9 cases (23%). S ix patients were spared laparotomy, and 3 others had PET-directed surgery t hat found extrahepatic tumor and spared the patient unwarranted liver resec tion. In 3 cases PET missed peritoneal metastases found on laparotomy. In t hese cases all missed tumors were less than 1 cm in size. Out of 52 resecte d hepatic lesions,F-18-FDG-PET detected 37. Within the liver, sensitivity o f detection was also related to size. Only 25% of hepatic lesions smaller t han 1 cm were detected by PET, while 85% of lesions larger than 1 cm were d etected. CONCLUSIONS: FDG-PET is best for detecting extrahepatic disease. There are few false positives, and surgeons should carefully evaluate and biopsy extr ahepatic positive sites. This test should be used for patients at high risk for extrahepatic disease and should be evaluated prospectively for all pat ients under consideration for liver resection. (C) 1999 by Excerpta Medica, Inc.