EUS-GUIDED CRYOTHERM ABLATION OF STAGE III PANCREATIC ADENOCARCINOMA: A PRELIMINARY RADIOLOGICAL PERSPECTIVE

Aims:

Cryotherm ablation is a hybrid bipolar ablative technique, combining radiofrequency thermal injury with a cryogenic gas. However, data on radiological perspectives are still lacking.

Aim: To evaluate differences in MDCT and DW-MRI imaging on tumor size and necrosis induced by the ERBE HybridTherm (HTP) probe.

Methods:

We evaluated consecutive patients with stage III pancreatic adenocarcinoma presented at our center from 02/2015 and 10/2017. These pts were enrolled in an ongoing randomized-controlled trial, belonging to chemotherapy+HTP treatment group. HTP ablation was conducted up to 3 times at 1-month interval. Patients underwent MDCT and DW-MRI scan 72h after treatment and at T0 and 2, 4 and 6 months after treatment began. We assessed the difference in tumor and ablation size and volume between CT and MRI. Data were considered for analysis if both imaging techniques were available for the same date. The paired T-Test and the Wilcokson matched-pairs signed rank test were used for statistical analysis.

Results:

15 patients (mean age 63 ± 11 years) underwent HTP treatment (mean 2.2 per pt) for locally advanced (11 pts) and borderline resectable (4 pts) disease. In 3 pts MRI was not feasible. A total of 41 MDCT and DW-MRI scans were identified. We observed no difference in tumor size between CT and MRI (p = 0.816 for long axis and p = 0.313 for short axis) as well as between MRI and ADC-Map (p = 0.120 and p = 0.431). Linear regression analysis for the comparison of both CT/MRI and MRI/ADC-Map showed a p =< 0.001. We reported a significant difference between CT and MRI size of the ablation zone, for both long and short axis (p = 0.0029).

Conclusions:

These data highlighted the agreement of both CT and MRI in tumor evaluation, whereas a significant difference in the evaluation of ablation necrosis, suggesting that DW-MRI with ADC-Map is essential in necrosis detection in responder patients.