Protontherapy of head and neck paragangliomas: A monocentric study

Purpose: The aim of this study was to assess efficacy and safety of proton beam therapy of paragangliomas of the head and neck, rare benign tumours developed close to crucial structures such as cranial nerves and vascular tissues.

Patients and methods: Ten patients with a paraganglioma of the head and neck were treated from 2001 to 2014 with image-guided proton therapy. Neurological and ear nose throat symptoms were collected in addition to audiometric testing, before and after the treatment. Acute and late toxicities were assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.

Results: Median age at diagnosis was 52.6years (range: 18.2-65.8years). Proton therapy was the exclusive treatment in six patients and four patients had a postoperative radiotherapy. Median dose was 50.4Gy relative biological effectiveness (RBE; range: 45.0-67.0Gy). With a median follow-up of 24.6months (range: 6.7-46.2 months), local tumour control rate was 100% (stable, n=10). No upper grade 2 acute toxicity was reported. To the latest news, seven patients had controlled symptoms (improved, n=1, stabilized, n=6). One patient out of seven with initial tinnitus had a decrease in his symptoms, while the six other patients had a sustained stabilization.

Conclusion: Proton beam therapy is an effective and well-tolerated treatment modality of skull base paragangliomas, with documented functional benefit. A longer follow-up is planned in order to assess local control and long-term toxicities.