Electric Pulses May Help in Pancreatic Ca
by Kristina Fiore, Staff Writer, MedPage Today 2012-03-29
SAN FRANCISCO -- A minimally invasive procedure that uses electrical pulses to target cancer cells may help make surgery an option for unresectable, locally advanced pancreatic cancer patients, researchers said here.
In a small trial, about a quarter of patients who had percutaneous irreversible electroporation (IRE) had their disease downstaged and were able to have surgery, Govindarajan Narayanan, MD, of the University of Miami, and colleagues reported during a press briefing at the Society of Interventional Radiology meeting here.
"This could be a new [therapeutic] option, with the potential to downstage patients to surgery," Narayanan said.
Patients with locally advanced disease aren't often candidates for surgery because their tumors are surrounded by pancreatic blood vessels. Chemoradiation can convert some patients to candidates for resection, but not all.
This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
A minimally invasive procedure that uses electrical pulses to target cancer cells may help make surgery an option for unresectable, locally advanced pancreatic cancer patients.
Note that the device used in this study, the NanoKnife, is FDA-approved for use in soft tissue and delivers high-voltage, low-energy direct current pulses to tumor cells via CT-guided electrode needles.
Clinicians also have tried ablative therapies, but these also run the risk of collateral damage to blood vessels, Narayanan explained.
Instead, irreversible electroporation delivers high-voltage, low-energy direct current pulses to tumor cells via CT-guided electrode needles. The bursts of energy perforate individual cells, ultimately leading to apoptosis, while sparing surrounding blood vessels.
The device used in this study, the NanoKnife, is FDA-approved for use in soft tissue. Use in organs is off-label, Narayanan noted, though it has been investigated in primary and metastatic liver cancer.
For their study, Narayanan and colleagues reviewed the records of eight pancreatic cancer patients who weren't eligible for surgery and had irreversible electroporation at their facility between December 2010 and September 2011.
The median patient age was 53, median time from diagnosis to irreversible electroporation was about nine months, and median tumor size was 8.8 cm.
All patients had had prior chemotherapy and seven had had prior radiation.
Overall, two patients became candidates for surgery, and were resected 4 and 5 months after the electrical procedure, the researchers said. Both patients had margin-negative resections and one had a pathologic complete response.
Both remain disease-free at 346 and 225 days after resection, Narayanan said.
Of the other six patients, one had progressive disease after 3 months, while another had a negative follow-up PET scan and surgery is planned.
Two other patients are still being monitored for the possibility of surgery, and two were lost to follow-up, he said.
He added that there were no major complications with the procedure and that it appears safe.
"We have not seen any major injury to blood vessels, and there are minimal side effects and morbidity," Narayanan said.
He called for larger trials to validate the results of this small study and estimated that within 2 years a sufficient body of evidence may have accumulated to support use of the therapy in pancreatic cancer.
Suresh Vedantham, MD, of Washington University in St. Louis, Mo., moderated the press briefing during which the results were presented. He said interventional radiology is opening up a wide range of options for cancer patients.
"Interventional oncology is becoming more of a pillar of oncology," he said, adding that interventionalists are looking to work more closely with all parties involved in cancer treatment.
Narayanan reported relationships with Angiodynamics.
Source Reference: Narayanan G, et al "Downstaging locally advanced pancreatic adenocarcinoma with vascular encasement using percutaneous irreversible electroporation (IRE)" SIR 2012; Abstract 8.