CLO19-032: Skin Cancer of the Nose: Outcome in 405 Cases Treated With Accelerated High Dose Rate Radiation Therapy

Overview: Between 2013 and 2016, we treated 1,500 cases of nonmelanoma skin cancer using high-dose radiation therapy. In this series, 405 cases involved the nose. Patient selection was limited to age >35 years, tumor size <40 mm in diameter and <5 mm thick. Demographics included 86.7% basal, 12.8% squamous, 1 lymphoma, 1 melanoma. Size by treatment field: 66.9% 10mm, 28.1% 20mm, 4.7% 35mm, and <1% 50mm. Age: 76.8 years median (37.3–99.7 years) Methods: Radiation therapy was administered following guidelines suggested by ASTRO and AAPM using either a 6MeV LINAC electron beam or 50kV x-ray source. The majority of patients received 4,000 cGy in 500 cGy fractions given twice weekly. Prescribed treatment depth was zero (0) mm for non-bulky disease. Bolus was used for all electron treatments. Wax-coated nasal shields were used for lateralized or large midline lesions. Devitalized tumor was debrided and/or treatment depth modified during treatment as needed. Treatment interruptions were rare, usually due to infection, and limited to less than 2 weeks. Results: 99% of patients maintained a complete response at 2 years (0.2–3.7 years) median follow-up, with 1 edge-of-field progression and 1 in-field recurrence. Side effects seen included transient nasal mucositis (10%) limited to lateralized or large midline lesions, superficial infection (<1%) limited to patients with a history of moderate to severe acne and/or patients applying cosmetic concealers during treatment. No chronic nasal dryness, cartilage necrosis, ophthalmic injury, nasolacrimal disruption, or dental complications occurred. Patient satisfaction/cosmesis: patient-scored functional and cosmetic outcomes ranged from very good to excellent in 100% of patients. Conclusion: Accelerated high dose rate radiation therapy using either LINAC electron beam or electronic brachytherapy is an effective and well-tolerated treatment option for carefully selected patients with basal and squamous cell skin cancer of the nose. Response rates for electron beam or low-energy x-rays with this dose schedule were similar. When compared to surgery, radiation therapy results in high patient satisfaction and excellent cosmesis without the need for lengthy postoperative care or reconstruction. When compared to conventional radiation therapy, the high response rates, smaller field sizes, shorter treatment times, and reduced radiation dose to adjacent critical tissues makes electronic brachytherapy a useful addition to standard techniques.