Pain: Persistent postsurgery and bone cancer-related pain

Abstract

The generation of neuropathic pain is a complex dynamic process. Factors involved include one or more dysregulated sensory neural pathways; dysregulated activity of specific neurotransmitters, synapses, receptors and cognitive and emotional neural circuits; and the balance between degenerative and regenerative neural events. Risk factors include age, sex, cognition, emotions, genetic polymorphism, previous or ongoing chronic pain conditions and the use of certain drugs. Intense pain experienced before, during and after surgery is a risk factor for the development of central sensitization with consequent persistent postsurgery neuropathic pain. Blockade of N-methyl-D-aspartate receptors with appropriate drugs during and immediately after surgery may prevent persistent postsurgical pain. Most cancers, but particularly malignant metastases in bone, can induce persistent pain. Local factors including direct damage to sensory nerve fibres, infiltration of nerve roots by cancer cells and algogenic biological agents within the microenvironment of the tumour bring about central sensitization of dorsal horn neurons, characterized by neurochemical reorganization with persistent cancer pain. In this article, the clinical features, pathogenesis and principles of management of persistent postsurgery pain and cancer pain are briefly discussed.

Selected pathobiological features and principles of pharmacological pain management

“…Whereas central sensitization related to inflammatory pain is resolved with the resolution of inflammation, central sensitization is the mechanism that both drives and maintains neuropathic pain. 8,61…”

“…Figure 2. Sequence of neural events caused by injury-induced inflammation (Adapted from Feller et al, 2019) 61. …”

Interrelations between pain, stress and executive functioning

“…3,29,32 Maladaptive response to chronic psychosocial stress or to chronic pain may include the onset of depression, anxiety and feelings of vulnerability, suffering and hostility, interfering with everyday activities such as eating, sleeping, working, social interactions and cognitive functions, thus significantly reducing quality of life. 35,36 The nature of the maladaptive response is determined by the type of the chronic stressor/pain and its severity and duration; by environmental, developmental, genetic and epigenetic factors and by the ability to mitigate or buffer the impact of the chronic stressor/pain via cognitive, emotional/spiritual, physical and pharmacological mechanisms 3,32,[35][36][37][38][39] (Table 2).…”

Effects of high-intensity training on the quality of life of cancer patients and survivors: a systematic review with meta-analysis

“…Short- and long-term 11 effects of cancer treatments have been shown to compromise patients’ HRQoL. Short-term effects include symptoms of fatigue 12 , weight loss 13 , weight gain 14 , sarcopenia and cachexia 15 , nausea/vomiting 16 , pain 17 , hair loss 18 , dyspnea 19 , insomnia (sleep disturbance) 20 , constipation 21 , and drowsiness 22 . Symptoms such as diarrhea, appetite loss, sore mouth, and sweating are also reported 23 .…”