Cancer pain matters and it is likely to matter even more in the coming years. Treatment advances have increased life expectancy for cancer patients, leaving them exposed to pain for longer, whereas pain management strategies have remained virtually unchanged for years, writes Bruno Damascelli, Milan, Italy.
In 2014, the American Cancer Society forecast that annual deaths due to cancer of the pancreas, liver, bile ducts, stomach, bowel, uterine cervix, bladder and prostate would total 176,000. A portion of these patients will develop visceral and neuropathic pain, of which 20% will become refractory to opiates and to all their possible combinations with steroids, non-steroidal anti-inflammatory drugs and neuroleptics. Between 5% and 7% of patients with intractable pain experience a severe deterioration in their quality of life, leading to a negative impact on social and family life and an increased burden on health services.
In recent years invasive pain management (neurolysis) has been introduced. These procedures are managed mainly by anaesthetists, gastroenterologists and neurosurgeons and aim to interrupt conduction of visceral and neuropathic pain signals from the structures affected by cancer to the higher nerve centres. As imaging methods have evolved, interventional radiologists have become involved and have begun to perform coeliac and upper hypogastric plexus blocks and neurolysis independently. The chemical and physical agents used are ethanol, phenol, heat (radiofrequency) and cold (cryoablation), which are difficult to apply and can give rise to significant complications. Up to 30ml of ethanol may be needed for coeliac plexus or coeliac ganglion block. It is unthinkable for such a large volume to remain confined to a small anatomical area after percutaneous infiltration.
Ablation of the nerve fibres that run in the artery wall became a reality a few years ago with the introduction of endovascular renal artery denervation for resistant hypertension. When applying this technique with the EnligHTN system (St Jude) we noticed that when the procedure was repeated in non-responders, it was not accompanied by the usual intense pain. It therefore seemed possible to apply the same method to other vascular districts such as the coeliac artery and the hypogastric arteries to obtain the same result as percutaneous neurolytic procedures based on infiltration of ethanol or phenol or application of radiofrequency.
The same electrodes and ultrasound probes already certified for renal artery denervation are used for ablation of the sympathetic nerve fibres that run in the walls of the coeliac and hypogastric arteries. Neurolysis occurs when the heat generated by ultrasound or radiofrequency is applied to the endothelium. The artery wall reaches a temperature of 70°C, which leads to degeneration of the nerve fibres. Introduction of the instruments is to all intents an angiographic percutaneous arterial catheterization procedure that can be performed under local anaesthesia via the femoral artery. At present the only exclusion criterion is anatomical inaccessibility. The reproducibility and safety profile using either radiofrequency or ultrasound are comparable to those reported for renal sympathetic denervation.
We have treated more than 20 patients with intractable cancer pain with radiofrequency to an average of 10 sites along the endoluminal surface following transfemoral catheterisation. The analgesic effect of this procedure has been assessed on a Visual Analog Scale (VAS) and mean score recorded for each patient during follow-up.
To date, in patients undergoing endovascular coeliac or hypogastric denervation for palliation of refractory abdominal cancer pain, the procedure has proved effective in durably reducing pain, particularly end-of-dose or breakthrough pain, and also in cutting down opiate consumption. We were particularly struck by a message from an anaesthetist whose father underwent endovascular coeliac neurolysis for pancreatic cancer pain, who said: “It is a month since you performed the procedure and, although my father is not doing well from a general point of view, he is doing well as far as pain is concerned and has almost stopped taking opiates”.
Bruno Damascelli is with the Department of Interventional Oncology, GVM Emocentrocuore Columbus, Milan, Italy. He has reported no disclosures pertaining to this article