Definitive Radiotherapy for Head and Neck Paragangliomas – A Single-Institution 30-Year Experience

Abstract

<h3>Purpose/Objective(s)</h3> To report local control (LC) and long-term toxicities following definitive radiotherapy (RT) in head and neck paragangliomas (HNPG). <h3>Materials/Methods</h3> All HNPG treated with definitive RT between 1990-2020 were reviewed. Patients with <1 year follow-up were excluded. The decision for RT instead of surgery was made together by the patient, surgical and radiation oncologists, considering expected efficacy and morbidity. Local failure (LF) was defined as growth of the tumor on imaging ± reappearance of or worsening symptoms. Late toxicity was recorded based on clinician's notes and attribution. The actuarial rates of LC and late toxicity were estimated using the competing risk method. <h3>Results</h3> Among 67 eligible patients, 33 (49%) had glomus jugulotympanicium (GJT), 18 (27%) carotid body (CB), 14 (21%) glomus vagale (GV), and 2 (3%) both CB and GV tumors. Six (9%) and 3 (4%) patients had 2 and 3 HNPGs, respectively. Three (4%) patients had malignant HNPGs; 4 (6%) had secretory tumors; and 4 (6%) had a family history of PGs. Active surveillance was adopted as the initial management strategy in 19 (28%) patients, among whom the median interval from diagnosis to initiation of RT was 4.5 years (range: 1.8-15.1). RT techniques evolved during the study period as shown in Table 1. The median follow-up of the entire cohort was 7.6 (1.1-32.3) years. One malignant GJT and 1 CB patient experienced LF based on imaging or persistent local symptoms potentially related to tumor. The patient with malignant GJT had a progressive asymptomatic neck mass on CT 4.5 years after RT, and was salvaged by surgery. The patient with CB tumor had persistent neck pain 1.9 years after RT despite stable disease on MR, and was controlled by pain medication. One CB (tinnitus), 1 GJT (stroke), and 1 GV (sensory nerve hearing loss) had potential RT-related toxicities occurring 6-, 9-, and 11-years post-RT, respectively. The 5-year LC rates for the entire cohort, GJT, CB, and GV subsets were 96% (85-99%), 96% (70-99), 94% (55-99), and 100%, respectively. The 10-year late toxicity rates for the entire cohort, GJT, CB, and GV subsets were 6% (1-23), 7% (1-51), 10% (1-74), and 0%, respectively. <h3>Conclusion</h3> HNPG patients benefit from multidisciplinary care. Modest dose (<50 Gy) radiotherapy is a safe and effective treatment modality in the management of HNPGs (especially for GJT tumors at skull base) with excellent rates of disease control and very low toxicity. Active surveillance may be suitable as an initial modality for properly selected HNPGs.