Pharmacological Treatment of Neuropathic Cancer Pain: A Comprehensive Review of the Current Literature

Abstract

Neuropathic cancer pain (NCP), commonly encountered in clinical practice, may be cancer-related, namely resulting from nervous system tumor invasion, surgical nerve damage during tumor removal, radiation-induced nerve damage and chemotherapy-related neuropathy, or may be of benign origin, unrelated to cancer. A neuropathic component is evident in about 1/3 of cancer pain cases.Although from a pathophysiological perspective NCP may differ from chronic neuropathic pain (NP), such as noncancer-related pain, clinical practice, and limited publications have shown that these two pain entities may share some treatment modalities. For example, co-analgesics have been well integrated into cancer pain-management strategies and are often used as First-Line options for the treatment of NCP. These drugs, including antidepressants and anticonvulsants, are recommended by evidence-based guidelines, whereas, others such as lidocaine patch 5%, are supported by randomized, controlled, clinical data and are included in guidelines for restricted conditions treatment. The vast majority of these drugs have already been proven useful in the management of benign NP syndromes. Treatment decisions for patients with NP can be difficult. The intrinsic difficulties in performing randomized controlled trials in cancer pain have traditionally justified the acceptance of drugs already known to be effective in benign NP for the management of malignant NP, despite the lack of relevant high quality data. Interest in NCP mechanisms and pharmacotherapy has increased, resulting in significant mechanism-based treatment advances for the future. In this comprehensive review, we present the latest knowledge regarding NCP pharmacological management. n INTRODUCTIONFollowing EFIC's (European Federation of IASP Chapters) declaration in 2001, pain is not a symptom but a disease in its own right, necessitating appropriate treatment. The word pain usually refers to a discrete sensory experience, triggered by an identifiable set of ''painful'' stimuli, acting on a unique or stable ''pain'' pathway and eliciting an invariant sensation. However, pain, and particularly neuropathic pain (NP) can also exist as a diverse group of complex phenomena of unpleasant and distressing nature. NP encloses numerous complicated neurobiologic constituents and reflects potentially dynamic mechanisms, interacting at multiple neuraxial sites. 1Modern neurobiological techniques have led to tremendous progress in the exploration of pain pathogenetic mechanisms. [2][3][4] Research indicates that pain can be produced in multiple ways, at different locations, co-existing between and across various pathological conditions. 5,6 Novel therapeutic targets have been discovered and are used by the pharmaceutical industry for the construction of highly specific molecules, acting as potential innovative analgesics. Recent targets' application, specific to precise NP mechanisms, will very soon enable treatment to be focused at particular mechanisms, introducing a mechanism-based therap...

Screening for Cancer-Related Neuropathic Pain in the Oncology Outpatient Setting in the United Kingdom

“…A greater proportion of patients with PainDETECT end scores of <13 received a diagnosis of neuropathic pain after examination of this questionnaire (36 of 127 [28.3%]) than patients with PainDETECT end scores of >18 (indicative that underlying CRNP was likely) who were considered not to experience neuropathic pain (three of 27 [11.1%]; Table 5). This trend is consistent with the findings of a recent review of pharmacologic treatments for CRNP that identified a shift from a trend of underdiagnosis of CRNP to hyperdiagnosis, explained by the researchers as a potential confusion between symptoms of neuropathic pain and hyperalgesia resulting from opioid administration [27]. Consequently, identifying screening tools that can help physicians characterise and diagnose the nature of pain is paramount to improving pain management in cancer patients, particularly as poor pain assessment has been identified as a contributing factor to the current undertreatment of cancer pain in general [28,29].…”

Anti-hyperalgesic effect of paracetamol in rat model of thermal hyperalgesia: implications for the treatment of neuropathic pain

“…15,16 GBP exert AHA action probably by acting in brain stem thereby causing descending inhibition and anti-allodynic action probably by altering microglial functions. 17 Beneficial effects of AMT in NP are independent of antidepressant action as indicated by requirement of low dose (25-100 mg daily) for analgesic action than antidepressant action. ADRs of AMT are common and around one third patient suffer from mild adverse effects while 8% of the patient stop taking drug due to severe adverse effects.…”

Macrophages as a Key Factor in the Process of Tumour From the Initiation to the Therapy of Cancer.

“…[119] Recently, it was reported that an anti-PD-L1 antibody, which blocks the PD-1/PD-L1 pathway, can improve macrophage-mediated T cell activation and has progressed to clinical trials. [120] www.wjpr.net …”