Long-Term Outcome and Comparison of Treatment Modalities of Temporal Bone Paragangliomas

SIMPLE SUMMARY: Temporal bone paragangliomas are rare benign skull base tumors. They are categorized according to Fisch or Glasscock–Jackson classification systems. The complexity of tumor location and extension into neighboring anatomical structures together with multiple treatment alternatives make it difficult to find optimal therapy for patients. In our retrospective study, we evaluated treatment strategies consisting of surgical resection, radiotherapy or radiosurgery and embolization over an extensive long-term follow-up period. We observed that especially small tumors (Fisch A and B) are best treated by surgical resection, and larger temporal bone paragangliomas (Fisch C and D) may be treated with combination therapy. Especially in larger tumors, evaluation in an interdisciplinary board is important. ABSTRACT: Introduction: Temporal bone paragangliomas are rare tumors with high vascularization and usually benign entity. A variety of modalities, including gross total resection, subtotal resection, conventional or stereotactic radiotherapy including gamma-knife, embolization, and wait-and-scan strategy can be considered. The aim of this study was to compare long-term outcomes of different primary treatment modalities in temporal bone paragangliomas. Materials and Methods: Patients with temporal bone paragangliomas treated between 1976 and 2018 at a tertiary referral center were retrospectively analyzed in this study. Collected patient data of 42 years were analyzed and long-term results including interdisciplinary management were assessed. Patient outcomes were compared within the different therapy modalities according to tumor control rate and complications. Clinical characteristics, radiological imaging, tumor extent and location (according to Fisch classification), symptoms, and follow-up were evaluated and a descriptive analysis for each treatment modality was performed. Tumor recurrence or growth progression and respective cranial nerve function before and after therapy were described. Results: A total of 59 patients were treated with a single or combined treatment modality and clinical follow-up was 7 (13) years (median, interquartile range). Of the included patients 45 (76%) were female and 14 (24%) male (ratio 3:1) with a patient age range from 18 to 83 years. Total resection was performed on 31 patients, while 14 patients underwent subtotal resection. Eleven patients were treated with conventional primary radiotherapy or gamma-knife radiosurgery. Pulsatile tinnitus (n = 17, 29%) and hearing impairment (n = 16, 27%) were the most common symptoms in our patient group. Permanent lower cranial nerve deficits were observed only in patients with large tumors (Fisch C and D, n = 14, 24%). Among the 45 patients who were treated surgically, 88% of patients with Fisch A and B paragangliomas had no recurrent disease, while no tumor growth was perceived in 83% of patients with Fisch C and D paragangliomas. Conclusion: In conclusion, we propose surgery as a treatment option for patients with small tumors, due to a high control rate and less cranial nerve deficits compared to larger tumors. Although patients with Fisch C and D temporal bone paraganglioma can be treated surgically, only subtotal resections are possible in many cases. Additionally, frequent occurrence of cranial nerve deficits in those patients and tumor growth progression in long-term follow-up examinations make a combination of the therapy modalities or a primary radiotherapy more suitable in larger tumors.