Celiac plexus radiosurgery may ease retroperitoneal pain syndrome

Ablative radiation delivered to the celiac plexus appears to reduce retroperitoneal pain syndrome in patients with cancer, according to a phase II study.

The multicentre, single-arm study included 125 adult patients (median age 65.5 years, 56 percent female) with either pancreatic cancer (92 percent) or other tumours involving the celiac axis, an average pain level of 5–10 on the Brief Pain Inventory short form (BPI-SF), and an Eastern Cooperative Oncology Group performance status score of 0–2. These patients received a single fraction of 25 Gy of external-beam photons to the celiac plexus.

The primary endpoint was complete or partial pain response based on a reduction of the BPI-SF average pain score of at least 2 points from baseline to 3 weeks after treatment. A total of 90 patients with stable pain scores were evaluable and included in response assessment.

At baseline, the median BPI-SF average pain score was 6. The primary endpoint was documented in 48 patients (53 percent, 95 percent confidence interval, 42–64).

In terms of safety, abdominal pain (28 percent) and fatigue (18 percent) were the most frequent grade 3–4 adverse events, irrespective of attribution. There were 11 serious adverse events of grade 3 or worse recorded. Of these, two were “probably” related to treatment (abdominal pain [n=1], nausea [n=1]), and nine were “possibly” related to treatment (seven were grade 3: blood bilirubin increase [n=1], duodenal haemorrhage [n=2], abdominal pain [n=2], progressive disease [n=2]; two were grade 5: gastrointestinal bleed from suspected varices 24 days after treatment [n=1], progressive disease [advanced pancreatic cancer] 89 days after treatment [n=1]).

The findings suggest that celiac plexus radiosurgery could potentially be a noninvasive palliative option for patients with retroperitoneal pain syndrome. A randomized controlled trial comparing radiosurgery with conventional celiac block or neurolysis is needed.