Radiotherapy alone yields excellent local control and overall survival rates in orbital lymphoma stage IE. Local irradiation is also well tolerated and effective in advanced NHL stages with orbital infiltration. Doses of > 36 Gy resulted in an increase of late complications.

Aims: Primary non-Hodgkin’s lymphoma (NHL) of the orbit is uncommon, representing approximately 8% of extranodal NHLs. Twenty-two patients with indolent stage IE NHL were reviewed retrospectively to analyze the outcome and late effects of primary local radiotherapy. Materials and Methods: The median age at first diagnosis was 63.5 years (range 24–82 years). Extranodal mucosa-associated lymphoid tissue lymphoma (n = 15) was the most common histological subtype of NHL, followed by follicular (n = 6) and lymphoplasmacytic lymphoma (n = 1). Radiotherapy was performed using a linear accelerator. The median radiation dose was 40 Gy (range 30–46 Gy). None of the patients received chemotherapy before irradiation. The follow-up period was 62 months (range 8–136 months). Results:A complete response was achieved in all patients. The 5-year local control rate was 100%. Distant relapse occurred in 2 patients, resulting in a 5-year distant relapse-free survival rate of 88%. The 5-year overall survival rate was 89%; there were no lymphoma-related deaths. No serious acute complications (grade 3/4) were observed. Grade 1/2 late effects were documented in 44% of patients. Grade 3 complications (cataract: 2, dryness: 2) were observed in 4 patients (18%). Conclusions: Indolent early stage orbital NHL can be controlled with local radiotherapy. Morbidity is low. Regular follow-up examinations are necessary to detect rare cases of distant relapse.