Purpose The Edmonton Classification System for Cancer Pain (ECS-CP) has been shown to predict pain management complexity based on five features: pain mechanism, incident pain, psychological distress, addictive behavior, and cognitive function. The main objective of our study was to explore the association between ECS-CP features and pain treatment outcomes among outpatients managed by a palliative care specialist-led interdisciplinary team. Methods Initial and follow-up clinical information of 386 eligible supportive care outpatients were retrospectively reviewed and analyzed. Results Between the initial consultation and the first follow-up visit, the median ESAS pain intensity improved from 6 to 4.5 ( p  < 0.0001) and the median total symptom distress score (0–100) improved from 38 to 31 ( p  < 0.0001). At baseline, patients with neuropathic pain ( p  < 0.001) and those with at least one ECS-CP feature ( p  = 0.006) used a higher number of adjuvant medications. At follow-up, patients with neuropathic pain were less likely to achieve their personalized pain goal (PPG) (29 vs 72%, p  = 0.015). No statistically significant association was found between increasing sum of ECS-CP features and any of the pain treatment outcomes at follow-up. Conclusion Neuropathy was found to be a poor prognostic feature in advanced cancer pain management. Increasing sum of ECS-CP features was not predictive of pain management complexity at the follow-up visit when pain was managed by a palliative medicine specialist. Further research is needed to further explore these observations.