Chen 2008.

Study characteristics
Methods	RCT, 3 arms
Participants	66 participants with cancer pain randomised to 3 groups: 'mild pain', 'moderate pain' and 'severe pain' Each of these 3 pain groups randomly divided into an acupuncture group and an oral medication group
Interventions	Group 1: acupuncture Group 2: oral medication group according to WHO 3 step administration in which participants in: mild pain were given aspirin moderate pain were given codeine severe pain were given morphine
Outcomes	Pain scores measured on a VAS, with response percentage calculated as [(score before‐score after)/score before] x 100 Analgesic effect reported from percentage difference in pain score. Complete relief (CR) 91%‐100%, average relief (AR) 61%‐90%, partial relief (PR) 31%‐60%, or no relief (NR) > 31%
Notes	Translated from Chinese
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation tables used to allocate subjects to the acupuncture or medication groups. It was not clear whether randomisation was carried out by blinded personnel
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not clearly stated
Blinding (performance bias and detection bias) All outcomes	High risk	Participant and evaluator blinding not described
Incomplete outcome data (attrition bias) All outcomes	High risk	Incomplete data and withdrawals not described
Other bias	High risk	Poor reporting of intervention and methodology Inadequate statistical analysis
Sample size	High risk	66 participants randomly allocated to 3 groups of 22