Refractory Cancer Pain

This trial aims to address refractory cancer pain (RCP). It will explore the synergistic efficacy and safety of hydromorphone hydrochloride sustained-release tablets (HHST) combined with electroacupuncture (EA) and ear acupoint pressing beans (EAPB) for RCP. Key outcomes will include dynamic changes in Numerical Rating Scale (NRS) scores, proportions of patients with effective analgesia (≥30% NRS reduction from baseline) and marked remission (≥50% NRS reduction from baseline), daily HHST dosage, breakthrough pain (BP) frequency, and drug-related adverse events (AEs) graded by CTCAE 5.0.