Low-dose radiotherapy for lymphoid lesions of the orbit and ocular adnexa.

Purpose: There is no agreement within the radiation oncology and ophthalmic communities regarding the treatment of lymphoid lesions of the orbit and ocular adnexa. The authors report their experience with the use of low-dose radiation therapy for malignant and benign lymphoid masses of the orbital region in a series of 54 patients treated between 1985 and 1993.

Methods: All patients received 2 Gy per day for a total of 24 Gy, except when the lesion was extensive, in which case the therapy was 1.5 Gy per day for a total of 25.5 Gy. A diagnosis was established by incisional surgical biopsy in 26 patients and aspiration cytology in 28 patients. Those with a malignant or an indeterminate diagnosis were evaluated with a modified Ann Arbor staging system.

Results: Low-dose radiation therapy produced a complete response in 100% of the orbital lymphoid lesions. This local control was maintained in 52 patients (96%) for the first year and in 51 patients (95%) for 5 or more years with a mean follow-up of 7 years. One patient died of causes unrelated to the malignant lymphoma after the first year of observation. The mean age of the 54 patients was 67 years, and the range was 37 to 90 years. The mean ages of presentation for each location were: orbit, 67 years; conjunctiva, 68 years; lacrimal gland, 66 years; and eyelids, 72 years. The female-to-male ratio was 1.25:1 (34 women and 20 men). In this series, 9 patients had benign processes, 38 patients had non-Hodgkin's lymphoma, and 7 patients had abnormalities of indeterminate cause. All histologic subtypes of non-Hodgkin's lymphoma involving the orbit responded equally well to therapy. Forty-five patients had clinically staged disease as follows: stage I, 21 patients; stage II, 4 patients; stage III, 2 patients; and stage IV, 18 patients. Benign disease, diagnosed in 9 patients, was not staged.

Conclusion: Low-dose radiation therapy proved effective in treating lymphoid lesions of the orbital area. No treatment-limiting complications occurred. The only early side effects were mild xerophthalmia and chemosis in 50% of patients, and the only chronic side effect was mild xerophthalmia in 33% of patients. Cataracts, corneal ulcerations, and retinal injury were not observed.