Radiation therapy of conjunctival and orbital lymphoid tumors.

Lymphoid tumors of the conjunctiva and orbit are rare and remain localized in the majority of cases. Sometimes it is not possible either clinically or histologically to differentiate between a non-Hodgkin's lymphoma (NHL) and benign lymphoid hyperplasia. A series of 24 patients is reported. Nineteen were classified as having malignant NHL and 5 benign hyperplasia; 1 of these 5 later developed metastases, however. All patients had systemic work-up: 18 had Stage I, 1 had Stage II, and 5 had Stage IV disease. All patients received local radiation therapy with doses of 2400 to 2750 rad in 2-3 weeks for lesions of the eyelid and conjunctiva, and between 3000 and 3750 rad in 3-4 weeks for retrobulbar lesions. The lens was shielded in all patients except in 2 who had NHL of the vitreous body. A method of shielding the lens with a lead block mounted on a "low vac lens" is described, and the dose distribution within the eye and orbit is presented. The dose to the ocular lens is reduced to about 10% of the tumor dose with this technique. Patients who were treated with doses higher than 3000 rad experienced conjunctivitis and skin erythema that resolved completely. No other effects of radiation on normal structures of the ocular adnexa were observed in the 20 patients who are alive and without signs of tumor 10-46 months with a median follow-up time of 22 months.