Neuromodulation for cancer pain treatment: which techniques are shown as more effective?

João Gustavo dos Anjos Morais Oliveira1, Luís Emanuel Reis dos Santos2, Ana Flávia Paiva Bandeira Assis1, Pedro Lucca Alves Bastos1, Roberta Veiga Pestana Visco Costa3, Gilcielma Gomes de Lemos2, Letícia Escorse Requião1.

1.Medical student at Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brasil. ; 2.Medical student at Universidade Federal da Bahia, Salvador, Bahia, Brasil. ;3.Medical student at Universidade Salvador, Salvador, Bahia, Brasil

OBJECTIVE: To analyse neuromodulation techniques and their efficacies in cancer pain treatments.

METHODS: The present study is a literature review. Literature reviews and systematic reviews were searched via PubMed, with descriptors taken from MeSH, published from 1980 to 2020, using the formula: (((neuromodulation) OR ("electric stimulation")) OR (Electrostimulation)) AND ("cancer pain"). Studies which did not match the objective of this review were excluded after analyzes of the title and abstract.

RESULTS: The search resulted in 159 articles, from which 38 were selected. Clinical trials and case reports have shown analgesia benefits on the use of ketamine as an adjuvant to opioids. Adjuvant drug use has been shown efficient on pain intensity reduction in cases which opioid therapy was not sufficient. In models, local cannabinoid injections have been shown effective on pain reduction in diverse cancer types. Clinical studies were conducted and have shown neuropathic pain reduction in oncologic patients especially on the use of a combination tetrahydrocannabinol and cannabidiol. Spinal electroestimulation is the most benefic surgical treatment. However, its use is not well established for all patients with cancer pain. It is surging new treatments such as intratecal bomb delivery systems; dorsal-root ganglion stimulation and peripheral nerve stimulation.

CONCLUSIONS: The neuromodulation, both chemical and electrical, has a favorable perspective on cancer pain treatment. However, it lacks concrete evidence, with bigger studies, for its disseminated use.

KEYWORDS: Cannabinoids; Ketamine; Opiods; Neuromodulation; Spinal Cord Stimulation; Dorsal Ganglion Stimulation.