癌痛在肿瘤患者中十分常见，严重影响患者的日常活动和生活质量。虽然世界卫生组织的三步镇痛阶梯对癌痛管 理起到积极作用，但仍有患者疼痛控制不理想。临床针对中度癌痛使用低剂量的强阿片类药干预取代二阶梯弱阿片类药物用 药尚存疑虑，证据尚不充足。本文针对该问题相关研究进行梳理，提示弱化二阶梯弱阿片类药物，直接采用低剂量强阿片类药 物对于中度癌痛进行干预，能有效控制疼痛，且不良反应较少，有利于提高患者的生活质量。临床镇痛治疗的疗效受到多因素 影响，除了二阶梯或者三阶梯用药区别外，患者接受各种抗肿瘤治疗的程度、不同性质的疼痛以及患者与医院的地域距离等都 会影响整体效果。做好中度癌痛的控制，需要临床医师多维度地进行评估和干预，本文从二阶梯与三阶梯治疗药物的药理、用 药的疗效、安全性以及相关影响因素等进行综述，以期为临床用药提供更多参考。

Patients with cancer often experience pain that affects their daily activities and quality of life. The inadequate pain treatments for patients who suffered from the moderate pain are still existed though the analgesic ladder recommended by the World Health Organization contributed outstanding. Current international guidelines recognize that low doses of a step Ⅲ opioid may be used instead of the step Ⅱ for patients with mild⁃moderate pain, although such recommendations are weak. These previous studies showed that to abolish the second step and start directly with a step three opioid will effectively control the pain better with less adverse effects. The effect of clinical analgesia treatment is affected by many factors. In addition to the different efficacy between the step Ⅱ and Ⅲ, the actual conditions such as cancer therapy (antitumor therapy or palliative care), pain types and living distance to the hospital affect the outcome of the patients. Therefore, clinicians need to formulate the analgesic strategy with multi⁃dimensional evaluations in order to improve the curative effect of moderate cancer pain. In our paper, we made efforts to evaluate the efficacy, tolerability and the factors related to adherence to long⁃term opioid therapy of low doses of morphine in comparison with standard doses of weak opioids in the treatment of moderate cancer pain in opioid⁃naive patients in order to provide more references for clinical job.