Importance of screening for synchronous malignant neoplasms in patients with hepatocellular carcinoma: impact of FDG PET/CT

Background & Aim: Synchronous neoplasms (SNs) are occasionally found in hepatocellular carcinoma (HCC). We examined such cases and the efficacy of 18-fluoro-2-deoxyglucose positron-emission tomography computed tomography (PET/CT), retrospectively. Materials and Methods: We investigated 687 naive HCC, who were admitted to our hospitals, encountered from October 2006 to December 2010 and evaluated the clinical backgrounds. All study protocols, was approved by our Institutional Ethics Committee. The usefulness of detecting SNs by PET/CT was evaluated in 234 patients who underwent PET/CT (PET group) and in 453 (non-PET group) examined in the same period. We noted the presence of SNs, defined as primary extrahepatic malignant neoplasms within 1year of diagnosis of HCC. Results: SNs were observed in 48 of 687 patients (54 tumours, 7.0%). SNs were detected by PET/CT in 18, which was 7.7% of PET group. The detection rate for SNs, were increased to 11.1% (26/234) in PET group by using together with upper gastrointestinal endoscopy and routine enhanced CT for HCC, which was greater than that of non-PET group (22/453, 4.9%) (P<0.001). Conclusion: SNs were pointed out more frequently in PET group than non-PET group (11.1% vs. 4.9%). FDG PET/CT can enhance the detection ability for SNs in naive HCC.