All too often, pain in cancer patients is not fully recognized or adequately treated. Inadequate pain management is due, at least in part, to the lack of a proper assessment of the experience of pain. And thus, improvement in the treatment of pain in cancer patients, furthermore, the possibility of prevention involves, among other things, the improvement of the assessment of pain. In this work, ... [Show full abstract] and as part of what should be a comprehensive assessment of patients with cancer and pain, the author provides an overview of the main tools to assess pain intensity. Not surprisingly, the reduction in pain intensity is the standard by which most pain treatments are judged.