Minimizing Eye Toxicity in the Treatment of Periorbital Nonmelanoma Skin Cancers

摘要

Nonmelanoma skin cancer (NMSC) is the most common malignancy worldwide and a major public health issue in Australia. The incidence of NMSC is increasing throughout the world in part because of the increasing age of the population and the increasing number of immunosuppressed patients. Periorbital NMSC is a serious problem because it can invade the bony cavity that contains the eyeball, the orbit. Basal cell carcinoma (BCC) is the most common among periorbital tumors, having a predilection for the lower eyelid and medial canthus. Squamous cell carcinoma (SCC) is also a common cancer of the eyelid. Orbital invasion occurs more frequently in SCC cases (5.9%) than in BCC cases (1.6-2.5%). Surgery is the gold standard in treating NMSC that has invaded the orbit because it offers the highest cure rate. However, patients may not proceed to surgery if they have certain comorbidities or if they refuse on the basis of operative morbidity. Radiation therapy is an alternative treatment option in such cases. The multidisciplinary radiation team may be reluctant to treat periorbital NMSC because of radiosensitive structures in the orbit, which can suffer side effects resulting from irradiation. In addition, a large differential in the radiosensitivity of eye structures can lead to further complication (see Table 1). The anterior chamber contains the bulk of the radiosensitive structures of the globe.