What factors influence treatment decision making in acoustic neuroma? Our experience on 103 cases

Acoustic Neuromas (AN) are benign tumors of the vestibulocochlear nerve with symptomatology that includes unilateral sensorineural hearing loss, tinnitus, dizziness, facial and/or trigeminal neuropathy. There are different treatment options of AN: watchful waiting, microsurgical resection, stereotactic radiation and the choice depends by many variables such age, health and hearing of patients as size, location and growing status of tumor. The objective of this retrospective study is to better understand the differences in demographic, hearing status, symptoms, tumor characteristics in patients affected by AN presenting at our clinic and analyze the factors that influence the therapeutic choice. One-hundred three patients affected by AN were included in the study. All subjects underwent a detailed clinical interview and audio-vestibular examination, and Magnetic Resonance Imaging (MRI). Tumor status, growing or stable was estimated comparing new size to any previous MRI with at least a 6-month interval. Descriptive statistics were used for clinical and demographic features of patients. Therapeutic choices related to subjective symptoms were assessed with the chi-square test. Treatment options in our sample included watchful waiting, surgical resection and stereotactic radiosurgery. Overall, 17 patients (16.5%) pursued surgical resection via the retrosigmoid approach, 3 patients (2.9%) were treated with gamma knife stereotactic radiosurgery and 83 patients (80.6%) underwent watchful waiting. The decision-making process for AN treatment was based on size of tumor, age, and hearing loss; a statistically significant difference was found at Z test about size of tumor and PTA of patients that underwent retrosigmoid surgery. No statistically significant difference was found at chi-square test between the type of treatment and symptoms (p=0.719). The analysis of the data showed that the main elements taken into consideration for surgery were the size of tumor (p<0.000004) and, secondly, the PTA threshold; the latter may be due to the fact that patients with bigger tumors had greater hearing impairment (p<0.001). Disease progression influenced the therapeutic decision making with a positive correlation between tumor progression and surgery (p<0.001). In our sample, active surveillance was the most adopted option for small tumor, slow growth and old age. Microsurgical resection was the preferred treatment in patients with large tumors, hearing deterioration and rapid growth. Stereotactic radiation has been proposed in a few cases of elderly patients with slow growing tumor and mild hearing loss.