The Role of Positron-Emission Tomography/Computed Tomography in Patients with Colorectal Liver Metastases who are Candidates for Liver Resection: Is it Useful?

Background: This study aimed to analyze the role of 18F-fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) as a preoperative diagnostic modality in patients with Colorectal Cancer Liver Metastasis (CRLM) who were candidates for liver resection. Oncologists have emphasized the usefulness of FDG-PET/CT. Considering the high cost of PET/CT examinations; it is unclear whether hepatectomy-candidates with CRLM should routinely undergo FDGPET/ CT. Methods: In the first term (2002 - 2008), we intended to identifythe criteria under which PET was recommended in a retrospectiveanalysis of 50 patients with CRLM. In the second term (2008 - 2013), 30 of 45 patients with CRLM underwent PET/CT by these criteria. The ability of PET/CT to detect extrahepatic lesions was compared with conventional radiologic modalities, such as enhanced CT and Magnetic Resonance Imaging (MRI). Results: In the first term, all 25 non-PET patients underwenthepatectomy, while hepatectomy was canceled in six of 25 PETpatients due to extrahepatic lesions. The prognosis after hepatectomy was similar between the PET and non-PET patients. Since each hepatectomy-canceled patient showed Fong's Clinical Risk Scores (CRS) of three or higher, we determined that the preoperative PET/CT should be performed when the CRS was greater than or equal to three. In the second term, extrahepatic lesions were identified in four of the 30 PET patients. These lesions were detectable under enhanced multi-detector row CT (MDCT). The lesion detection rate for PET/CT was similar to that of MDCT. Disease quickly recurred after hepatectomy in the PET group (median disease-free duration 10.5 versus 60.0 months), suggesting that preoperative PET/CT did not benefit hepatectomycandidates with CRLM. Conclusion: In the hepatectomy-candidates with CRLM, PET/CT is not always a necessary diagnostic modality.