Radiation therapy for stage I primary orbital non-Hodgkin's lymphomas

The orbit is an uncommon primary site for non-Hodgkin's lymphomas (NHL), and it accounts for less than 1% of all sites of primary presentations. We report the experience of the Department of Radiation Oncology at Ankara University Faculty of Medicine with radiation therapy in treatment of patients with stage I primary orbital NHL.

From February 1978 through August 1993, 14 patients with stage I primary orbital NHL were treated with radiation therapy. According to the Working Formulation classification, 8 patients had low-grade and 6 had intermediate-grade lymphomas. The most commonly used radiation therapy technique was a single anterior field with a Cobalt-60 unit, delivering 40 Gy in 2 Gy daily fractions. Two patients with intermediate-grade lymphomas received the CHOP regimen following radiation therapy.

Follow-up ranged from 0.8 to 18.3 years (median, 10.3 years). Local control was achieved in all patients. Two patients with low-grade lymphomas relapsed locally and were successfully salvaged with radiation therapy. Three patients with intermediate-grade lymphomas failed systemically. Salvage therapy consisted of combination chemotherapy for 2 of them but was unsuccessful. Overall survival probabilities at 2, 5 and 10 years were 78.6%, 61.1% and 52.4%, respectively, for the entire group of 14 patients. Overall, cause-specific and disease-free survival probabilities were higher for patients with low-grade lymphomas than for those with intermediate-grade lymphomas (P = 0.03, P = 0.03 and P = 0.06, respectively). Cataracts were observed in 9 and lacrimal disorders in 4 patients.

The study suggests that among stage I primary orbital NHL, low-grade lymphomas could be treated with radiation therapy alone, whereas combination chemotherapy could accompany radiation therapy for intermediate-grade lymphomas.