Initial experience using percutaneous irreversible electroporation (IRE) in the treatment of locally advanced pancreatic adenocarcinoma (LAPC) with vascular encasement.

Abstract

291 Background: Neoadjuvant chemoradiation therapy can convert some patients (pts) with borderline or unresectable LAPC to resectability. Persistent vascular encasement after neoadjuvant therapy usually contraindicates resection. IRE using the Nanoknife is more versatile than other ablative modalities in that tumors abutting vascular structures can be treated with IRE without compromise of the vessels or concern for the heat sink effect of nearby blood flow. Methods: We examined the records of pts referred for IRE for LAPC. The procedures were all done percutaneously under general anesthesia using a standard protocol. The primary endpoint was safety. Secondary endpoints included survival and resection rate after the procedure. Results: Between 12/2010 and 8/2011, 8 pts with biopsy-proven PC underwent percutaneous ablation of pancreatic tumors using IRE. The median age was 53 years (range 51-72), the median time from diagnosis to IRE was 8.8 months (range 2.4-29.2) and the median tumor size treated was 2.8cm (range 2.5-6.8). All pts had prior chemotherapy and 7 had prior radiation, with a median of 2 lines of prior therapies (range 1-4). Two pts went to surgery after IRE after 4 and 5 months respectively. Both had margin-negative (R0) resections and one had a pathologic complete response. Both remain disease-free at 1 and 5 months after resection respectively. Among the 6 remaining pts, 2 were lost to follow-up, one had progressive disease after 3 months and 3 remain under follow-up to determine resectability. One of these 3 pts had a negative follow-up PET scan and surgery is planned. The procedure was complicated by a spontaneous pneumothorax during anesthesia in one patient, and another developed pancreatitis; both recovered completely. Conclusions: Percutaneous ablation of pancreatic tumors appears to be feasible and safe using the IRE modality. In our initial experience, 2 out of 8 pts with unresectable LAPC due to persistent vascular encasement after neoadjuvant therapy achieved a margin-negative resection after IRE. One had a pathological complete response. A prospective neoadjuvant trial in LAPC incorporating IRE is planned.