Curative radiation therapy for primary ocular lymphomas: Demonstration of dose response.

Abstract

e18503 Background: Orbital lymphomas (OL) are rare and account for less than 1% of all cases of non-Hodgkin lymphoma. Radiotherapy (RT) alone provides good local control rates (97-100%) for extranodal marginal zone lymphoma (MALT) of the orbit. We report the outcomes of OL patients treated at FCCC. Methods: Between 1991 and 2008, 23 patients (28 eyes, 5 bilateral, 20%) treated at FCCC with local radiation therapy for orbital lymphoma were reviewed. Treatment consisted of 24-36 Gy,1.5-2.5 Gy per fraction (median 30 Gy in 20 fractions) of RT to the orbit using 6 MV photons. Patient, tumor and treatment related factors including age, stage, histology, type of treatment, RT details and late side effects were analyzed for the local control rates (LC), relapse free and overall survival (OS) by number of patients and orbits independently. Results: The median follow-up was 27 months (range: 1-123 months). The median age was 72 years (range: 37-87), 11 were females, 12 males. Most common presenting symptom was proptosis (74%). 20 patients had tumor in orbit only, 2 in conjunctiva only and 1 in both conjunctiva + orbit. Histology was MALT in 13 patients, and other low grade B cell NHL in 10. The 5-year LC and OS rates were 95%, 63% by patients and 96%, 68% by orbits respectively. The 5-year LC rate at patient level for MALToma was 91% versus 100% for other NHL histologies (p=0.3) and 100% for RT dose ≥ 30 Gy versus 75% for < 30 Gy (p = 0.04). One patient had both systemic + orbital relapse and systemic relapse was seen in two. The median interval to first relapse was 25 months (0.99- 122.37). On univariate analysis including age (≤ 70 versus > 70 years), stage (IAE vs others), histology (MALT versus others), and location of tumor (orbit vs others), there was no difference in outcomes except for RT dose (≥ 30 Gy vs < 30 Gy) for LC (p = 0.04). 4/23 patients had three lines of improvement in Snellen's visual acuity after one year of treatment. Minimal dry eye was seen in 77% patients. Five patients developed cataracts. There were no late effects like corneal ulcer, papillopathy or secondary glaucoma. Conclusions: Radiation therapy alone is the extremely effective in the curative management of primary localized orbital lymphoma. RT dose of 30 Gy provides better LC rates. No significant financial relationships to disclose.