18F-FDG PET/CT performed immediately after percutaneous ablation to evaluate outcomes of the procedure: preliminary results

Abstract

ObjectiveTo determine whether 18F-fluorodeoxyglucose positron emission tomography/computed tomography performed immediately after percutaneous ablation (iPA18F-FDG PET/CT) is useful in evaluating the outcomes of the procedure.Materials and MethodsThis was a retrospective study of 20 patients (13 males, 7 females; mean age, 65.8 ± 12.1 years) submitted to percutaneous ablation of metastases. All of the lesions treated had shown focal uptake on a 18F-FDG PET/CT scan obtained at baseline. The primary tumors were mainly colorectal cancer (in 45%) or lung cancer (in 40%). iPA18F-FDG PET/CT was performed to identify any residual viable tumor cells. The treatment was considered a success (no viable tumor cells present) if no uptake of 18F-FDG was noted on the iPA18F-FDG PET/CT scan.ResultsTwenty-six lesions were submitted to percutaneous ablation with either cryoablation (n = 7) or radiofrequency ablation (n = 19). The mean lesion diameter was 2.52 ± 1.49 cm. For the detection of viable tumor cells, iPA18F-FDG PET/CT had a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 66.7%, 95%, 88.5%, 80%, and 90.5%, respectively. There was a significant correlation between the iPA18F-FDG PET/CT findings and the results of the follow-up studies (kappa = 0.66; p < 0.01).ConclusioniPA18F-FDG PET/CT studies appear to constitute a useful means of evaluating the outcomes of percutaneous ablation. By detecting residual viable tumor cells, this strategy might allow early re-intervention, thus reducing morbidity. Studies involving larger numbers of patients are needed in order to confirm our findings.

Use of PET/CT to aid clinical decision-making in cases of solitary pulmonary nodule: a probabilistic approach

“…A number of recent studies conducted in Brazil have emphasized the importance of nuclear medicine, especially 18 F-FDG-PET/CT, for the diagnosis and follow-up of various illnesses (14)(15)(16)(17)(18) . The present study showed how 18 F-FDG-PET/CT can aid clinicians during the decisionmaking process in cases of SPN with an intermediate probability of malignancy.…”

Cryoablation of Lung Metastases: Review of Recent Literature and Ablation Technique

“…A small series consisting of a mixed population of primary and metastatic malignancy and cryoablation and RFA showed that PET/CT performed immediately following IGTA is effective in confirming complete ablation and predicting recurrence. 46 Recurrent tumor can usually be retreated with cryoablation with size and location considerations the same as with untreated lesions.…”

Is 18F-FDG PET/CT a real breakthrough imaging test in predicting the outcome of percutaneous ablation of metastases?

“…Another aspect that would be very interesting to investigate is the value of iPA 18 F-FDG PET/CT in improving overall survival and recurrence-free survival rates in a highly selected group of patients, in comparison with that of the standard approach (performing only imaging studies during a follow-up period of the standard duration). Although we still cannot answer the question raised by this editorial, the Romanato et al ( 6 ) article provided very interesting insights into the use of 18 F-FDG PET/CT after percutaneous ablation of malignant cells in a selected group of patients.…”

“…Albeit a relative expensive tool for local or segmental evaluation, iPA 18 F-FDG PET/CT had a false-positive rate that was low (7.6%), although it was still higher than that reported in patients referred for PET/CT performed at a time point that was slightly longer after ablation ( 7 ) . As very well discussed by Romanato et al ( 6 ) , that difference might be partially explained by the fact that a lung tumor treated with cryoablation and liver metastasis from colorectal cancer treated with radiofrequency ablation were included in the same group for analysis. The relatively low sensitivity in detecting a viable tumor is dependent not only on the amount of viable cells still present after ablation but also on many other biological features that might be impaired immediately after ablation, such as the enzymatic activity of hexokinase, proliferation activity of the tumor cells (in the vicinity and within the target), and hypoxia-inducible factors in the periphery of the treated lesion.…”

“…A very interesting paper published in the previous issue of Radiologia Brasileira , authored by Romanato et al ( 6 ) , represents the first study enrolling patients that were referred for 18 F-FDG PET/CT performed immediately after percutaneous ablation ( iPA 18 F-FDG PET/CT). The authors showed a good correlation between the iPA 18 F-FDG PET/CT findings and those of the follow-up imaging studies.…”