Postoperative Pain: Associated Cancer and Behavioral Disorders (Part 3)

Postoperative pain remains one of the most pressing problems of modern surgery, anesthesiology, clinical pharmacology, and clinical pharmacy. Inadequate control of postoperative pain is associated with delayed functional recovery, poor quality of life, and increased risk of chronic pain. The problem is of particular importance in cancer patients, in whom pain is often of a mixed nature, develops against the background of a pre-existing pain syndrome, previous use of opioids and pronounced psycho-emotional distress. Postoperative pain in patients with associated behavioral disorders (anxiety, catastrophizing, avoidance of activity, sleep disorders) has a mutually reinforcing negative effect: pain exacerbates behavioral disorders, and the latter exacerbate the subjective intensity of pain. The aim of the work was to summarize modern data on the clinical and pharmacological mechanisms of postoperative pain, to characterize associated oncological and behavioral disorders, and to analyze the role of opioids in postoperative pain relief. The study was carried out in the format of a systematic literature review using the principles of PRISMA 2020, which ensure transparency and reproducibility of the selection and analysis of publications. The analysis included clinical guidelines, systematic reviews, meta-analyses, narrative reviews, and original studies on postoperative pain, multimodal analgesia, opioid therapy, endosurgery, and behavioral disorders. The results showed that postoperative pain is formed under the influence of peripheral and central sensitization, inflammatory response, and psycho-emotional factors, which justifies the need for a multimodal approach to pain relief. Anxiety, catastrophizing pain, sleep disturbances, avoidant behavior, and hyperfixation on bodily sensations have been found to enhance the subjective perception of pain and impair postoperative rehabilitation. Opioids remain important in the treatment of severe postoperative pain, but their use is limited by the risk of sedation, respiratory depression, nausea, constipation, tolerance, and continued use after surgery. In cancer patients, postoperative pain management requires a personalized, opioid-sparing, and multidisciplinary approach, considering chronic pain, possible opioid tolerance, neuropathic pain component, and somatic weakness. Effective management of postoperative pain should be based on the principles of early pain assessment, multimodal analgesia, limitation of unnecessary use of opioids, and individualization of therapy, especially in cancer patients. Considering behavioral and psycho-emotional factors can increase the effectiveness of anesthesia, improve functional recovery, and reduce the risk of chronic pain.