Prospective Randomized Controlled Clinical Study of Acupoint Application With Gutong Plaster in the Treatment of Moderate to Severe Cancer Pain

This clinical trial aims to evaluate the efficacy and safety of acupoint application with Gutong Plaster for treating moderate to severe cancer pain in patients aged ≥18 years with moderate to severe cancer pain (NRS 4-8), ECOG 0-3, life expectancy ≥3 months. The main questions it aims to answer are: Does acupoint application with Gutong Plaster improve the response rate (CR + PR) in patients with moderate to severe cancer pain? Does Gutong Plaster reduce pain intensity (NRS score) and opioid consumption in cancer pain patients? Researchers will compare patients receiving oxycodone plus Gutong Plaster to patients receiving oxycodone plus placebo simulant to see if Gutong Plaster provides better pain relief and lower opioid use. Participants will: Receive standard treatment with oxycodone prolonged-release tablets Be randomly assigned to receive Gutong Plaster or placebo simulant via acupoint application twice daily for 14 days Undergo pain assessment, quality of life evaluation, safety laboratory tests, and follow-up at specified time points