“…11 Undertreatment of pain affected the patients' physical function, impaired psychological well-being, interfered with social interactions, increased the utility of hospital resources, and compromised the effectiveness of anti-tumor treatment. 13,14 The barriers to adequate cancer pain control were multi-factorial, and were often attributed to clinicians, patients, families, and social reasons. Therefore, knowledge of the prevalence of undertreatment of pain, and identification of the vulnerable subjects, may assist in enhancing patients' care and achieving better outcomes.…”