Proton Therapy of Paranasal Sinus Tumors: The UFPTI Experience

Introduction: Ten patients with tumors in the paranasal sinus region with skull base extension have received high-dose proton therapy at UFPTI since January of 2007. The disease characteristics, treatment planning, and delivery techniques and initial follow-up results are presented.

Methods: Of the 10 patients, 8 had prior surgery, 4 with positive margins. Two patients had biopsy only. Histology included poorly differentiated carcinomas, sinonasal undifferentiated carcinoma, adenocarcinoma, mucosal melanoma, and adenoid cystic carcinoma. Proton treatment targets and critical structures were delineated from coregistered simulation CT images and diagnostic MR images. The geometric relations between target volumes and critical structures were examined to select optimal proton beam parameters. Proton-specific through- and patch-fields as well as match-fields were used for these patients to achieve target-conforming and critical organ-sparing concave dose distributions. Prescribed dosage ranges from 69.6 CGE to 74.4 CGE, delivered at 1.2 CGE per fraction, two fractions per day. Treatments were delivered with orthogonal kV x-ray imaging guidance, to achieve 1 mm patient setup accuracy, for each fraction.

Results: Patient follow-ups ranged from 1 to 8 months, with a mean of 3.4 months. All patients tolerated treatments well. Patients had brisk skin reactions that resolved within 4 weeks after completion of treatments. Follow-up CT and MR scans revealed no evidence of disease recurrence. Visual and neurological functions were preserved for all patients at last follow-up.

Conclusion: Our experience suggests that patients with tumors involving the skull base will benefit from high-dose conformal proton therapy treatments.