Delivery of radiation to the celiac plexus can decrease pain and opioid use among patients with pancreatic cancer, according to a phase 2 trial presented at the 2022 ASTRO Annual Meeting.
“Pancreatic cancer is characterized by a particular retroperitoneal nerve syndrome of epigastric pain that radiates to the lower back, and this pain is often severe, debilitating, and difficult to treat,” explained study presenter Yaacov Lawrence, MD, of Sheba Medical Center in Ramat Gan, Israel.
“The pain is thought to be caused by infiltration or pressure on the celiac nerve plexus, which lies immediately posterior to the pancreas itself,” he added.
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Dr Lawrence and colleagues hypothesized that radiotherapy targeted to the celiac plexus would relieve this pain and have limited side effects.
The team tested this theory in a study of patients with pancreatic cancer or any cancer involving the celiac blood vessels. The patients had an average pain level of 5 or more on an 11-point scale despite analgesia, an ECOG performance status of 0-2, and a life expectancy of at least 8 weeks.
A total of 125 patients received radiation (25 Gy to the celiac plexus), and 90 were evaluable for analysis. The median age of the patients was 65 years (range, 28-88), 92% had pancreatic cancer, and 86% had metastases. Patients had received a median of 1 prior lines of systemic therapy (range, 0-5). The median pain level at baseline was 6 (range, 4-10), and the mean opioid use was 54.0 mg (range, 0-328) of morphine equivalent units.
The primary endpoint was complete or partial pain response on the Brief Pain Inventory at 3 weeks. At that time, 53.3% of patients (48/90) had at least a partial pain response.
Total daily opioid use was similar at baseline and 3 weeks — 54.0 mg and 54.2 mg, respectively — but it decreased significantly by 6 weeks, to 37.3 mg (P =.005).
The use of short-acting opioids decreased from 6.9 times per day at baseline to 5.0 times per day at 3 weeks (P =.03) and to 3.2 times per day at 6 weeks (P =.01).
There were minimal adverse events, Dr Lawrence said. Five serious adverse events were possibly related to treatment, including hyponatremia, jaundice, duodenal hemorrhage, and duodenal ulcer.
“We consider this a new possible treatment option for cancer pain emanating from the celiac plexus,” Dr Lawrence concluded.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Lawrence Y, Miszczyk M, Dawson LA, et al. Celiac plexus radio-surgery for pain management in advanced cancer: An international phase II trial. ASTRO 2022. October 23-26, 2022. Abstract LBA6.
