Radiation Therapy for Orbital and Adnexal Tumors

Abstract

Radiation therapy is used in the multimodality treatment of many orbital and adnexal tumors to enhance local control and possibly, in some patients, overall survival. In this chapter we will review the indications, modern techniques, potential toxic effects, and expectations of tumor control for a variety of orbital and adnexal tumors. Typically, treatments are delivered in fractions of 1.8-2.0 Gy per day, with the total number of fractions depending on the inherent radiosensitivity of the lesion. Radiotherapy technique and field design depends on the required dose, the tumor type, and the surrounding normal structures such as the lens, which is at risk of a cataract after a dose as low as 2 Gy. Excellent functional outcomes are evident for patients with optic nerve meningiomas with 5-year local control rates greater than 90% after local radiation therapy alone. In patients with orbital rhabdomyosarcoma, chemotherapy with radiation therapy results in excellent 5-year survival rates. Recently, we have been evaluating the role of oculoplastic procedures followed by adjuvant radiation therapy in lieu of orbital exenteration for patients with locally advanced ocular adnexal cancers.