Intensity-modulated radiation therapy for orbital lymphoma

Purpose: Orbital manifestations of non-Hodgkin\u27s lymphoma (NHL) are rare and accounts for only 1% of all cases of NHL. There have been no reports of treating orbital lymphoma using intensity-modulated radiotherapy (IMRT). Materials and methods: Four patients were treated at our institution for orbital lymphoma using IMRT. Radiotherapy (RT) plans using wedged pair fields were developed for comparison. Clinical results using IMRT are presented and a dosimetric analysis between IMRT and RT was performed. Results: All patients had a complete response based on their physical examinations and post-IMRT imaging. Symptoms that had been present at initial presentation resolved in all patients during the course of the treatment. All four patients experienced only grade 1 dry eye syndrome and keratitis. The average dose to the contralateral orbit, lacrimal gland, and lens were all significantly reduced (P \u3c 0.01) in IMRT patients as compared to the RT patients. IMRT reduced the V5 and V10 for the contralateral lens, orbit, and lacrimal gland and the optic chiasm (P \u3c 0.05). Conclusion: IMRT is feasible when treating orbital lymphoma and reduces dose to critical structures while providing excellent dose coverage of target volumes. IMRT offers patients with orbital lymphoma excellent clinical outcomes, similar to conventional RT, with no increased toxicity. © 2008 Japan Radiological Society