Noninvasive Brain Stimulation for Cancer Pain Management in Nonbrain Malignancy: A Meta-Analysis

Abstract

Purpose. Noninvasive brain stimulation (NIBS) has been reported to have analgesic effects on fibromyalgia and chronic neuropathic pain; however, its effects on cancer pain have yet to be determined. The present study aimed to evaluate the effects of NIBS on patients with pain secondary to nonbrain malignancy. Methods. Electronic databases including PubMed, Embase, Cochrane Library, and Web of Science were searched from inception through June 5th, 2022. Parallel, randomized, placebo-controlled studies were included that enrolled adult patients with cancer pain, except for that caused by brain tumors, compared NIBS with placebo stimulation, and reported sufficient data for performing meta-analysis. Results. Four parallel, randomized, sham-controlled studies were included: two of repetitive transcranial magnetic stimulation (rTMS), one of transcranial direct current stimulation (tDCS), and one of cranial electrical stimulation (CES). rTMS significantly improved pain in the subgroup analysis (standardized mean difference (SMD): −1.148, 95% confidence interval (CI): −1.660 to −0.637, ( p < 0.001 )), while NIBS was not benefited in reducing pain intensity (SMD: −0.632, 95% CI: −1.356 to 0.092, p = 0.087). Also, NIBS significantly improved depressive symptoms (SMD: −0.665, 95% CI: −1.178 to −0.153, p = 0.011), especially in the form of rTMS (SMD: −0.875, 95% CI: −1.356 to −0.395, p < 0.001 ) and tDCS (SMD: −1.082, 95% CI: −1.746 to −0.418, p = 0.001). Conclusion. rTMS significantly improved pain secondary to nonbrain malignancy apart from other forms of NIBS without major adverse events.

Cancer Pain and Non-Invasive Brain Stimulation—A Narrative Review

“…The results are encouraging, with rTMS providing benefits for pain suppression in patients with cancer. This is supported by a recent meta-analysis [21] that included two of the rTMS trials [25,27]. They showed a better effect on pain with rTMS compared to CES and tDCS, but this could be attributed to the fact that tDCS and CES have been represented with only one trial.…”

“…All three studies had an IMMPACT recommendation score of four. None of the studies discussed below were included in the Cochrane analysis, whereas the 2023 meta-analysis by Chien [21] included Lyon's study published in 2015 [32].…”

“…Even though these new techniques are mentioned in articles presenting advances in cancer pain management [19,20], no comprehensive review of the existing data exists. Recently, a systematic review and meta-analysis was performed on just four trials involving noninvasive brain stimulation in patients with cancer [21].…”

The Application of tDCS to Treat Pain and Psychocognitive Symptoms in Cancer Patients: A Scoping Review

“…It is noteworthy that, in addition to implementing tDCS sessions, the literature [62][63][64] has demonstrated the effectiveness of other NIBS techniques, such as TMS, in managing pain and psychocognitive symptoms in cancer patients. In particular, it has been observed that repetitive transcranial magnetic stimulation (rTMS) significantly reduces the intensity of pain and depressive symptoms in patients with nonbrain malignancy tumors [65]. rTMS indeed has a greater and more focused electric field compared to tDCS [66].…”

“…rTMS indeed has a greater and more focused electric field compared to tDCS [66]. On the other hand, some NIBS techniques, including cranial electrical stimulation (CES), do not show a significant reduction in pain and depressive symptoms in cancer patients [65]. However, tDCS remains the more widely adopted technique due to its advantages such as simplicity and potential for remote application, thus enabling more frequent sessions [16].…”