Outcomes of primary lymphoma of the ocular adnexa (orbital lymphoma) treated with radiotherapy

Abstract

Aims: Low-grade ocular adnexal lymphoma is a rare disease and often treated with local radiotherapy to varying doses. Most previously reported studies have a very heterogeneous patient population and treatments. We report the outcomes from a 10 year cohort of patients at our institution treated with primary radiation therapy.

Materials and methods: We analysed a retrospective case series of patients with stage IE low-grade ocular adnexal lymphoma including a review of case notes, histological reports and radiotherapy charts. We assessed local and distant tumour control and relapse rates in addition to toxicity. Disease-free survival was estimated using the Kaplan-Meier method.

Results: In total, 81 patients and 85 orbits were treated with primary radiotherapy to a median dose of 30 Gy in 15 fractions over 3 weeks. Seventy-nine per cent were treated with standard MV external beam radiotherapy to the whole orbit and 21% with a lens-sparing technique. The median follow-up was 4.4 years (range 0.2-10.4). Local control rates were 100%, with 5% of patients experiencing disease relapse elsewhere. No patients died from lymphoma. Cumulative acute toxicity rates were 51% (mainly erythema and conjunctivitis) and late toxicity rates were 8% (mainly cataract). The lens-sparing technique was associated with a significant reduction in cataract rate (P = 0.013) and an increase in acute toxicity (P < 0.001).

Conclusions: This study has shown excellent local control rates and acceptable toxicity from the treatment of stage IE low-grade ocular adnexal lymphoma with localised radiotherapy to a median dose of 30 Gy in 15 fractions over 3 weeks.

Keywords: Lens-sparing radiotherapy; ocular adnexal lymphoma; ocular radiotherapy.