Prospective evaluation of 18F-fluorodeoxyglucose positron emission tomography in patients receiving hepatic arterial and systemic chemotherapy for unresectable colorectal liver metastases

BackgroundThe prognostic and predictive abilities of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) coupled with conventional computed tomography (CT) have not been studied in patients with unresectable colorectal liver metastases (uCRLM) treated with combined hepatic arterial infusion (HAI) and systemic chemotherapy. ObjectivesThe ability of PET-CT metabolic response parameters to predict conversion to resectability and oncologic outcome in this setting was evaluated. MethodsThirty-eight patients undergoing serial PET-CT as part of a Phase II trial of HAI and systemic chemotherapy for uCRLM were included. Metabolic response was determined as the percentage change in standard uptake value (SUV) and total lesion glycolysis (TLG). Conversion to resection, overall survival (OS), progression-free survival (PFS) and recurrence-free survival were evaluated using standard statistics. ResultsVolumetric response sufficient to facilitate resection was seen in 53% of patients after a median of 5months of therapy. Median follow-up was 38months (range: 32-52months). Median OS was not reached [95% confidence interval (CI) 32months-unknown] and 3-year OS was 54% (range: 33-71%). Median PFS was 13months (95% CI 6-21months) and 3year PFS was 10% (range: 3-20%). Neither baseline values nor the percentage change in any of the metabolic parameters evaluated correlated with conversion to resection, survival variables or hepatic recurrence on Cox regression analysis. ConclusionsPre- and post-treatment PET-related metabolic parameters do not predict conversion to resection or oncologic outcome in patients with uCRLM treated with HAI and systemic chemotherapy. Metabolic parameters should not be used to monitor response or to determine prognosis in these patients.