1Division of Radiation Oncology, Department of Oncology, Yokohama City University, Graduate School of Medicine, Japan
2Department of Radiology, Yokohama City University Graduate School of Medicine, Japan
Primary orbital lymphoma is a rare malignancy that accounts for only 1% of all lymphomas, and more than half of orbital lymphomas present histology of marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). MALT lymphoma is an indolent and slow growing disease that is very radiosensitive. Radiation therapy is thus the first choice of curative treatment for MALT lymphoma. The total dose of approximately 30 Gy in conventional fractions has been most frequently used for the treatment of MALT lymphoma, and has achieved an excellent local control rate of ≥ 95%. Recently, the total dose has been reduced to 24 Gy to 25 Gy in some institutions. Furthermore, low dose irradiation with 4 Gy in 2 fractions is also given, but the long-term efficacy is still unclear even though the initial response is good. In contrast, higher dose irradiation with >30 Gy is not recommendable, because there is no evidence that such higher doses enhance the efficacy of local control, and because higher doses can cause unacceptable toxicities, such as severe retinopathy.
Malignant lymphoma; Mucosa-associated lymphoid tissue lymphoma; Orbit; Orbital lymphoma; Radiation therapy
Hata M. Radiation Therapy for Orbital Mucosa-Associated Lymphoid Tissue Lymphoma: What is the Optimal Radiation Dose? Ann Radiat Ther Oncol. 2017; 1(2): 1012.