O. E. Ojo1,2, J. Antone3,4, Y. R. Wuu1,3, B. Gui1,2, J. Starner1,4, J. D. Nosrati4, C. Stanzione5, N. Seetharamu1,6, and M. Ghaly1; 1Northwell, Lake Success, NY, 2Department of Radiation Medicine, Northwell, Lake Success, NY, 3Northwell, Department of Radiation Medicine, Lake Success, NY, 4Northwell, New Hyde Park, NY, 5Half Hollow Hills West High School, Dix Hills, NY, 6Department of MedIcal Oncology, Northwell, Lake Success, NY
Purpose/Objective(s):The management of locally advanced periorbital skin tumors is challenging, especially in those with orbital invasion. 0rbital exenteration has long been considered the gold standard. This study assesses the efficacy and toxicity of stereotactic body radiation therapy (SBRT) as a treatment option in the new paradigm shift towards ‘eye-sparing’ strategies. Materials/
Methods: This is a retrospective analysis of thirteen patients with locally advanced periorbital tumors who were prospectively treated with SBRT. Tumors involve canthi (zone III or IV) in eight patients with more than one zone involvement in two. Three patients presented with complete periorbital skin invasion (zone V). Eleven tumors violated the orbital septum, with anterior orbital space invasion in eight and middle orbital space involvement in three. Extraconal violation was seen in eight patients and intraconal invasion in five. All presented with intact vision in the ipsilateral eye. SBRT with simultaneous boost (35- 40Gy/ 25Gy) delivered in five biweekly fractions. Maximum point dose to “Orbit-PRV and Optic N PRV” were limited to 30 Gy. Lacrimal gland mean dose to < 30 Gy when it was feasible. Local/regional recurrence and treatment-related toxicity were evaluated using CTCAE grading. Statistical analysis utilized the data management and decision management software (or statistical software) version. Results: Eleven patients presented with primary skin tumors (squamous cell carcinoma in six, basal cell in four, and one with Merkel cell cancer), and two presented with advanced orbit solitary fibrous tumor in one and metastatic breast cancer to orbit. SBRT was delivered as definitive therapy in seven patients and as adjuvant therapy in six. All patients completed their treatment. Median PTV volumes were 34 cc (PTV 25), 9cc (PTV35-40 Gy), D90 34/41.5 Gy. After a median follow-up of 9 months, all patients presented with intact vision. Eleven had no evidence of local recurrence. Two remained with stable disease. All had Grade 1 dermatitis during radiation treatment and 4/13 patients had Grade 2 dermatitis. Grade 3 dermatitis was observed in two patients, and one patient underwent skin graft construction. Eight patients were medically treated for Grade 1 conjunctivitis. One patient was treated for symptomatic cataracts, and one had alopecia of the eyebrows. Three patients had Grade 1 epiphora. Conclusion: This study identified that SBRT may offer an alternative to exenteration and standard radiation fractions in the management of periorbital skin cancers. In this small cohort, SBRT offers a safe and effective therapeutic option in the context of “eye-sparing” strategies. Toxicity was minimal, ocular function was maintained, with excellent local control. These results suggest the advance to perform a prospective study to address the role of a nonsurgical option for these clinical scenarios.
