KEY POINTS
- This retrospective University of Pennsylvania series included 52 adults with 54 non-metastatic head and neck paragangliomas treated between 2008 and 2020. Tumors included 30 jugular, 8 jugulotympanic, 11 carotid-body, 3 vagal, 1 tympanic and 1 spinal paraganglioma.
- Treatment was deliberately individualized rather than comparative: 22 tumors received proton therapy, 23 SRS and 9 IMRT. Median dose across modalities was 45 Gy-equivalent; median EQD2 was 49.6 Gy for proton therapy, 49.6 Gy for IMRT and 34.7 Gy for SRS.
- Modality selection reflected anatomy and treatment era. Proton-treated lesions were substantially larger—mean volume 45.5 cm³ versus 9.42 cm³ with SRS and 12.91 cm³ with IMRT—and protons were preferentially used for large, skull-base, recurrent or anatomically complex disease.
- After median follow-up of 50.3 months, overall local control was 98%, distant control 100% and all 52 patients were alive. Local control was 95% after proton therapy and 100% after SRS and IMRT, but these rates cannot be interpreted as comparative effectiveness because treatment groups differed profoundly at baseline.
- Radiographic stability rather than major shrinkage was the dominant post-treatment pattern: 53/54 tumors (98%) were stable or partially responsive, while 20 tumors (37%) shrank by at least 20%. Regression occurred in 36% of proton-treated, 35% of SRS-treated and 44% of IMRT-treated lesions.
- No grade 3–5 toxicity was reported. Grade 1 toxicity occurred in 88% of patients and grade 2 toxicity in 38%; common acute events included fatigue, dysphagia, headache, dermatitis, mucositis and xerostomia. Pre-existing and treatment-associated cranial neuropathies were common given the skull-base anatomy.
- The only local failure occurred after proton reirradiation of a previously operated lesion that had received IMRT 17 years earlier. The institution currently favors SRS for small well-circumscribed lesions and generally avoids it above approximately 16 cm³, while using protons for larger or more complex tumors.
CLINICAL TAKEAWAY
Radiotherapy provides extremely durable control for appropriately selected head and neck paragangliomas, and this series suggests that protons can manage substantially larger and more complex lesions without high-grade toxicity. It does not show that one modality is superior: tumor size, anatomy, previous treatment and treatment era dictated modality choice.