Proton beam therapy of periorbital sinonasal squamous cell carcinoma: Two case reports and review of literature

BACKGROUND: Sinonasal malignancies are rare but demanding due to complex anatomy, usually late diagnosis, and inconsistent therapy strategy based on multimodality approaches. Squamous cell carcinoma (SCC) is the most common histology, with poorer prognosis. In the setting of orbital invasion, an orbital exenteration may be required. However, in case of primary rejection of disfiguring surgery or unresectable disease, proton beam therapy (PBT) should be largely considered, allowing for better sparing of neighboring critical structures and improved outcomes by dose escalation. CASE SUMMARY: A 62-year-old male presented with a recurrent SCC in the nasal septum abutting frontal skull base and bilateral orbits at 7 mo after primary partial nasal amputation. Because of refusal of face-deforming surgery and considerable adverse effects of conventional radiotherapy, the patient underwent a PBT by hyperfractionated accelerated scheme, resulting in complete response and moderate toxicities. After 2 years, a nasal reconstruction was implemented with satisfactory appearance and recurrence-freedom to date. Another patient with an initially extended sinonasal SCC, invading right orbit and facial soft tissue, declined an orbital exenteration and was treated with a normofractionated PBT to the gross tumor and elective cervical lymphatics. The follow-up showed a continuous tumor remission with reasonable late toxicities, such as cataract and telangiectasia on the right. Despite T4a stage and disapproval of concurrent chemotherapy owing to individual choice, both patients still achieved outstanding treatment outcomes with PBT alone. CONCLUSION: PBT enabled orbit preservation and excellent tumor control without severe adverse effects on both presented patients with locally advanced sinonasal SCC.