Radiotherapy in the management of orbital lymphoma.

PURPOSE: This retrospective study reviews the treatment technique, disease outcome, and complications of radiotherapy used in the management of lymphoma involving the orbits. PATIENTS & METHODS: Thirty-eight patients were treated between May 1969 and January 1995, with a median follow-up of 8.3 years. All patients had biopsy-proven orbital lymphoma. Twenty patients who had limited disease were treated with curative intent, and 18 patients who had known systemic disease were treated with palliative intent. Of the 20 patients treated with curative intent, 14 had low-grade and 6 had intermediate- or high-grade disease. None received chemotherapy. Most patients received treatment with 250 kVP or 60Co radiation, using either an en face anterior field or wedged anterior and lateral fields. Median treatment dose was 25 Gy. Lens shielding was performed if possible. For patients treated for cure, cause-specific survival and freedom from distant relapse were calculated using the Kaplan-Meier method. RESULTS: Control of disease in the orbit was achieved in all but 1 patient, who developed an out-of-field recurrence after irradiation of a lacrimal tumor and was salvaged with further radiotherapy. In the patients treated curatively, the 5-year rate of actuarial freedom from distant relapse was 61% for those with low-grade and 33% for those with intermediate/high-grade disease (p = 0.08). Cause-specific survival at 5 years was 89% for patients with low-grade and 33% for those with intermediate/high-grade disease (p = 0.005). Two patients with low-grade disease had contralateral orbital failures; both were salvaged with further irradiation. Acute toxicity was minimal. Cataracts developed in 7 of 21 patients treated without lens shielding and 0 of 17 patients treated with lens shielding. No patient developed significant late lacrimal toxicity. CONCLUSION: Radiotherapy is a safe and effective local treatment in the management of orbital lymphoma.