Proton Beam Therapy for Advanced Periocular Skin Cancer: An Eye-Sparing Approach.

Background/Objectives: The management of periocular skin malignancies presents a unique challenge. Proton beam therapy, due to its sharp dose fall-off, allows for the delivery of a tumoricidal dose to the tumor while sparing adjacent normal tissues. Methods: Thirteen patients with a median age of 76.5 years received protons at our institution to a median dose of 66.6 Gy (RBE). Sixty-four percent of the lesions were basal cell carcinoma, and 22% were squamous cell carcinoma. Eighty-six percent of patients underwent biopsy only or partial resection. Fifty-seven percent of the lesions were located in the medial or lateral canthus. There was orbital invasion in 93% of the cases. Locoregional control probability and overall survival were estimated with the Kaplan-Meier method. Treatment toxicity was scored using the CTCAE 4.0. Results: At a median follow-up of 96 months, there was no local recurrence. The rate of orbital preservation was 100%. Functional vision was maintained in all the patients. There was no acute or late grade 3 or higher toxicity. Conclusions: Protons allow for long-term tumor control with eye preservation in patients with locally advanced periocular skin cancers. Larger prospective multi-institutional trials with standardized ophthalmological assessments are needed to confirm our findings.