Cochlear implants in the etiopathogenesis of glioblastoma–an interesting observation or independent finding?

Abstract

Various risk factors have been implicated in the pathogenesis of glioblastomas including ionizing radiation. Recent evidence has suggested a possible association between exposure to nonionizing radiofrequency electromagnetic fields (RF-EMF) generated from mobile phones and wireless devices to cause malignant transformation of the neuroglial cells, albeit this is widely debated. In this report, we discuss the development of glioblastoma in two geopolitically unrelated patients, an elderly male from the United States and a middle-aged woman from Sweden, with long-standing cochlear implants (CI). We hypothesize that the low-frequency RF-EMF emanating from the transcutaneous link of the CI prosthesis over a long period has potentially triggered tumor development in these patients.

Occurrence of primary brain tumors in cochlear implant patients in Sweden between 1989 and 2014

“…Contrary to the concerns raised by our recently published case report, 6 we did not find an increased risk of malignant glioma, meningioma, or schwannoma in our cohort of patients with cochlear implants. The RF-EMFs generated by a cochlear implant are thus unlikely to induce tumors.…”

“…We cannot rule out that a more highly powered study would find weak associations between exposure and tumor incidence. Still, the only patient with a glioblastoma among the cochlear implant patients in Sweden was our one Swedish index case in the case report (the other was from the USA) 6 and the absence of additional patients is indicative of low risk. Various risk factors have been associated with glioma, 8 but cochlear implants were only suggested in our previous report of two cases of glioblastoma after long-term cochlear implantation.…”

“…Various risk factors have been associated with glioma, 8 but cochlear implants were only suggested in our previous report of two cases of glioblastoma after long-term cochlear implantation. 6 In these cases, the anatomical relation to the implant antennas was compelling, but two patients are a very small proportion of the more than 500,000 cochlear implant recipients around the world. Furthermore, our present findings were based on the comprehensive population-based Swedish registers, ensuring complete follow-up, which is a strength.…”

“…We have recently reported on two cases of glioblastoma in geographically unrelated patients, one from Sweden and the other from the USA, who had long-standing cochlear implants. 6 Extrapolating from the discussions regarding mobile phone use, the two cases raised concerns that long-term exposure to low levels of RF-EMF emanating from the transcutaneous link of the cochlear implant could increase the risk of neurological tumors in patients with cochlear implants.…”

Deep brain stimulation and glioma

“…The authors speculate that electric fields associated with the treatment could have caused the tumour. The authors also mention a case report describing the development of glioblastoma in two patients who had cochlear implants, where it was suggested that the tumours might be attributed to the electromagnetic fields from the implants [5]. Both of these are interesting observations, although alternative explanations for the occurrence of the tumours in these patients may be at least as, or even more, plausible.…”