Background: The advent of endoscopic ultrasound guided celiac plexus neurolysis (EUS-CPN) has provided immeasurable benefits for patients with pain from pancreatic malignancies. Here, we aim to characterize efficacy of various agents used in EUS-CPN for reducing pain secondary to pancreatic cancer by performing a systematic review and meta-analysis.

Methods: Using predefined keywords, a search was performed using PubMed, Medline, and Cochrane databases during the last 30 years. An initial search identified 130 relevant articles and seven studies fit inclusion criteria (N = 291). Criteria used to assess the quality of studies included randomization, selection bias, blinding outcome, concentration, and types of agents for neurolysis. The meta-analysis was performed by calculating pooled proportion of patients with pain relief. Clinical outcome was defined as ratio of patient who reported improvement of pain within 4 to 8 weeks of intervention. Forrest plots were drawn to show the point estimates in each study in relation to the summary of pooled estimates. Cochran’s Q test was used to calculate heterogeneity. A Pearson’s Chi-Square test was used to estimate the significance of the relationship between EUS-CPN and adverse outcomes.

Results: The agents used in the studies were 98%, 99% and 99.5% of alcohol, Iodine 125 seeds, 7% phenol and 0.7 g phenol and 60% glycerol. Among the total of 291 patients pain relief achieved on 80.2% (95% CI = 75.5% – 85%) in 4 to 8 weeks. The test of heterogeneity gave a p value of 0.85, suggesting there were no significant difference in between utilizing different concentration of alcohol percentage or different agents for CPN. A Forrest plot showing the summary estimates was shown in Fig. 1. Additionally, adverse events were charted and found to have a Pearson’s Chi-square value of 36.0, with a df of 7, and p-value < 0.001, showing a statistically significant association between using with alcohol, phenol, phenol with glycerol, or Iodine as substance for neurolysis and potential side effects. Phenol and Iodine based neurolysis had adverse events mainly related to worsening pain and alcohol had adverse events related to hypotension and transient diarrhea.

Conclusions: Overall, there is no significant difference in outcome between using different agents or concentrations of alcohol during the celiac plexus neurolysis. While adverse effects have been shown to be related to EUS_CPN, the side effect profile varies wildly, depending on substance used for neurolysis and concentration percentage.

IMAGE 1: Figure 1: Forrest plot showing the individual study proportion of pain relief in relation pooled proportions of pain relief in patients with pancreatic cancer