Endovascular Radiofrequency Neurolysis for Refractory Abdominal Cancer Pain

Endovascular radiofrequency neurolysis was originally developed on the basis of our experience with endovascular renal artery denervation for treatment of resistant hypertension. In 2014 we began to study the use of endovascular celiac artery denervation to alleviate chronic pain due to pancreatic adenocarcinoma and other abdominal malignancies. In view of the favorable results, we later introduced denervation of the hypogastric arteries for pain from pelvic tumors. 

Our technique copies what is done through celiac plexus neurolysis with alcohol, celiac plexus block with steroids, radiofrequency splanchnic nerve ablation, and hypogastric plexus block with alcohol. These procedures are not widely used because they are difficult to perform and carry significant complications. They are carried out percutaneously, surgically, under endoscopic ultrasound guidance, and they require various technical resources and specialists.

The aim of celiac and hypogastric endovascular radiofrequency denervation is to improve control of chronic refractory cancer pain through a procedure that is simpler than those proposed to date. Also the goal is to identify an option that is less invasive, safer, more reproducible and with few exclusion criteria. Percutaneous arterial catheterization is used to insert a radiofrequency electrode designed for ablation of the sympathetic fibers that run in the adventitia of the vessels. The sympathetic and parasympathetic fibers that originate from the retroperitoneal ganglia and those of the vagus nerve follow the celiac trunk and the superior and inferior mesenteric arteries. The superior and inferior hypogastric plexi are the pathways for transmission of pelvic pain and their fibers follow the hypogastric vessels.

Histologic tests carried out on the renal arteries of experimental animals and on human autopsy specimens show that the heat induced by radiofrequency or ultrasound in endovascular mode can bring about regressive changes in the nerve fibers that run in the adventitia up to a distance of 7 mm from the endothelium, interrupting conduction of both afferent and efferent stimuli.

Any of the devices designed for endovascular radiofrequency and used until now for renal sympathetic denervation can be used for analgesic denervation. We use the EnligHTN system produced by St. Jude Medical, with some modifications. The procedure involves percutaneous catheterization via the femoral artery of the celiac arteries for upper abdominal cancers and of the hypogastric artery on one or both sides for pelvic cancers. For this specific use we have developed a steerable sheath (Destino Twist TD, Oscor), which has a double pre-shaped curve that can be accentuated or decreased by manipulating a rotating collar on the handle. A CT or MR angiography is first performed to map the vascular anatomical conditions. The celiac or hypogastric artery is engaged for an angiographic check and then the electrode is introduced into the artery. After making sure that the four active points are in correct contact with the vessel wall, radiofrequency is delivered with automatic control of power, temperature, and impedance. One-minute delivery can be repeated along various sections of the artery, depending upon its length. The sheath is optimized for the diameter of the electrode, allowing roadmapping navigation of the electrode, which is steerable. Radiofrequency can also be delivered to the initial portion of the hepatic and/or splenic artery, depending upon the topography of the malignancy.

The heat produced by the radiofrequency causes pain due to stimulation of the sensitive fibers which normally corresponds to the site of the pain reported by the patient. Additional opioid analgesia, accessible without changing the patient's ongoing treatment, is usually necessary during this stage of the procedure. On completion, hemostasis is achieved through manual compression or using a dedicated system.

At the time of this publication we have considered 16 candidates for the procedure and excluded one because access was anatomically impossible. In all 15 cases, the safety profile was good. The procedure required only one night in hospital and there were no local problems at the access site or general problems. All patients had previously complained of chronic pain that was not controlled by maximum doses of opioids, NSAIDS, and steroids. The VAS score was markedly reduced in almost all patients (80%), allowing opioid doses to be reduced by about 30%. The analgesic effect lasts for about 2.5 months, but this a preliminary finding because the follow-up is still limited. In one patient with a re-exacerbation of pain after 2.5 months, denervation was repeated with renewed efficacy.

In Europe, the use of endovascular radiofrequency electrodes carries the CE mark only for use in the renal arteries to treat drug-resistant hypertension. Celiac and hypogastric denervation are to be considered off-label and subject to special regulatory standards. Our first results were obtained in patients with refractory pancreatic cancer pain, which still represents the main experimental indication, making this procedure particularly relevant to interventional oncology clinicians. Pancreatic adenocarcinoma is among the malignancies most frequently associated with severe pain for which medical treatment based on narcotics is inadequate. This pain is often refractory to opioids, whose side effects increase with increasing doses. A nonpharmacologic support characterized by excellent feasibility and safety is highly desirable to preserve the patient's quality of life. In addition to these extreme conditions related to terminal diseases, we believe that with the development of suitable instruments, the same technique can be used to treat other benign causes of chronic visceral pain.

Editor’s note: This article did not undergo peer review.

Suggested citation: Damascelli B, Tichà V, Patelli G. Endovascular radiofrequency neurolysis for refractory abdominal cancer pain. Intervent Oncol 360. 2015;3(11):E137-E140.