Can a causal relationship be established between acoustic neuroma and occupational exposure to non-ionizing radiations from mobile devices? Comparison between scientific literature data and medico-legal methodology

Background. Over the process of establishing the causal relationship, medical and legal methodologies may be at variance over the definitional standards and terminologies applied, which can hinder the activities of expert witnesses. Objectives.The article's authors have set out to assess whether, and under what conditions, a causal relationship can be established between acoustic neuroma and exposure to non-ionizing radiation from mobile communication devices. Methods. The study design is a Systematic Review. The authors have drawn upon a 2020 Turin Court of Appeals ruling which found such a causal relationship in a somewhat peculiar case: rare tumor and exposure to non-ionizing radiation of unusually long and regular duration. The case presents several peculiarities, herein analyzed in light of a) scientific evidence relative to the etiopathogenesis of the neuroma; b) available medico-legal literature defining causality evaluation criteria, and lastly c) court filings in regard to the probability standards applied to prove causal relationship. Results.A direct tie cannot be proven, not even in cases of substantially intense and lengthy exposure, if the medico-legal standards applied are not consistent enough to prove that nexus is more likely than not. Discussion. Several elements suggest a causal relationship is unlikely: a) a dearth of evidence on humans; b) rats exposed to such radiation have developed cardiac tumors, not in their ears; c) exposure has caused no tumors in mice; d) the length of exposure is incompatible with tumor size and type. That fourth point only concerns the case herein explored, whereas the first three have a general scope of validity. The main limitation of the present study design is the heterogeneity among the included studies. Retrospective and prospective studies have been included, which may be a source of bias.