A Pilot Comparison of 18F-fluorodeoxyglucose and 18F-fluorocholine PET/CT to Predict Early Recurrence of Unifocal Hepatocellular Carcinoma After Surgical Resection

Objective: Presurgical identification of patients at high risk for early recurrence of hepatocellular carcinoma (HCC) after resection could warrant additional therapies. F-fluorodeoxyglucose (FDG) uptake by the tumour on preoperative PET can predict HCC recurrence after resection as effectively as poor differentiation or presence of microvascular invasion (MVI) on postsurgical histology. A better sensitivity for the detection of HCC nodules has been reported with F-fluorocholine (FCH), a PET tracer of lipid metabolism. This pilot study aimed to compare preoperative FDG and FCH PET/CT for predicting early recurrence of unifocal HCC, occurring within 6 months after surgical resection.

Methods: FDG and FCH tumour uptakes were assessed on preoperative PET/CT by two masked readers. On FCH PET/CT, a photopenic lesion and a hot focus were considered as indicative of malignancy. During postoperative follow-up, recurrence was searched for by regularly performing CT and MRI.

Results: In 11 consecutive HCC patients, the detection rate was greater with FCH (80%) than with FDG (27%). After resection, the overall recurrence rate was 55%. Early recurrence occurred in four patients, who were the only ones with an FDG-positive and FCH-photopenic tumour, with a significant reduction in disease-free survival. On postsurgical histology, those four patients also presented with MVI and satellite nodules. Histological differentiation and capsule disruption appeared less accurate than PET/CT or MVI in predicting early recurrence.

Conclusion: In unifocal HCC, the FCH photopenic pattern was associated with MVI and predicted early HCC recurrence after surgical resection as accurately as did an FDG uptake. Larger studies with FCH are warranted.