Authors:
C. N. Patel, R. Briggs, F. U. Chowdhury, A. F. Scarsbrook; Leeds/UK
DOI:
10.1594/ecr2010/C-0251
Conclusion
Our study has demonstrated that FDG PET/CT can detect additional sites of metastatic disease, predominantly extrahepatic which may be occult on conventional imaging.
For colorectal liver metastases, PET/CT detected additonal sites of disease in 43% of cases with a change in management in 17% of patients. Previous reports suggest the detection of extrahepatic disease may alter management in up to 32% of patients with longer 3 year survival rates in those undergoing curvative resection following PET/CT [3-5].
Cholangiocarcinomas may show variable FDG avidity, greater in peripheral nodular tumours than infiltrating hilar types. FDG PET/CT has greater sensitivity than CT for intrahepatic tumours and comparable sensitivity for extrahepatic lesions [6,7]. Our study detected additonal sites of disease in 35% of cases with a change in management in 13% of patients. In keeping with prior studies, FDG PET/CT is more useful for detecting distant metastases rather than local nodal disease. Again, changes in management have been reported in up to 30% of patients [8-11]
Gallbladder carcinomas are often discovered late or incidentally following cholecystectomy for benign disease. FDG PET/CT has been shown to alter management in those being considered for primary resection or re-resection in 10% of patients [10,11]. Additional sites of disease, predominantly distant metastases were found in 50% of cases in our study although this altered management in only 20% of patients. The relatively small number of patients is likely to account for the high percentage of occult disease in our study.
The limitations of using FDG PET/CT include the variable FDG avidity of some hepatobiliary tumours, the intrinsic resolution to detect small lesions and sources of false-positive PET (such as inflammatory/infective causes which require correlation with inflammatory markers).
Overall, 18F-FDG PET/CT has incremental value in detecting additional sites of occult disease in patients with hepatobiliary malignancy prior to potentially curative surgical resection and alters planned management in almost 1 in 5 patients.