Objective   This study aimed to analyze the factors affecting the outcome of cancer pain in patients with moderate and severe chronic cancer pain for clinical decision making.

  Methods   Data were collected from 426 cancer patients with moderate and severe chronic cancer pain, and the factors affecting pain treatment were analyzed.

  Results   A total of 85.6% of patients had good pain control in 3 days (NRS≤3). Multivariate logistic regression models showed that the pain of patients with bone metastases (P=0.026), breakthrough pain after stable pain control (P < 0.001), and high MEDD (P < 0.001) was poorly controlled. Moreover, age, sex, TNM stage, cause of pain, and medication ladder were not risk factors of pain control (P > 0.05). Opioid combination with NSAIDs contributed to easier pain control (P=0.024). Digestive system tumors, pain intensity, limb pain, neuropathic pain, use of transdermal fentanyl matrix patch, multiple metastases in stage-IV patients were suggested to be risk factors of pain control in univariate logistic regression models (P < 0.05).

  Conclusions   Bone metastases, breakthrough pain after pain relief, and high dose of MEDD were independent risk factors. Opioid combination with NSAIDs was a protective factor of pain control.