RCT on Intralesional Rituximab Injection Versus ISRT in Ocular Adnexal MALT Lymphoma

Inclusion criteria 1. Age between 18 to 75 years old. 2. Ocular adnexal MALT lymphoma with a comprehensive diagnosis based on pathology, clinical manifestations, and biological characteristics according to the WHO classification of tumors of hematopoietic and lymphoid tissues. 3. Based on the TNM staging of ocular adnexal lymphoma, patients with stages T1-3 of ocular adnexal MALT lymphoma without involvement of intraconal compartment are included. 4. Willing to participate the trial and sign the informed consent form. Exclusion criteria 1. Based on the TNM staging of ocular adnexal lymphoma (Table 1), patients staged as T2/T3 with involvement of intraconal compartment and patients staged as T4. 2. Patients who have previously received local or systemic radiation, chemotherapy, or drug treatment specifically for ocular adnexal MALT lymphoma. 3. Presence of cataract and is anticipated to require surgical treatment within a certain period after enrollment; existing cataract affects visual field testing and fundoscopic examination; vision affected by cataract is \<20/40. 4. In addition to the need for treatment of ocular adnexal MALT lymphoma, there is a requirement for other ocular procedures (e.g., full-thickness corneal transplant or retinal surgery) or an anticipated need for another emergent ocular surgery. 5. Complicated with other ocular diseases: including corneal abnormalities or existing corneal infections, iridocorneal endothelial syndrome, anterior segment dysgenesis, true microphthalmos, uveitis, glaucoma, ocular trauma, and retinal disorders such as central retinal vein occlusion, central retinal artery occlusion, retinal detachment, etc. 6. The statue of HBV or HIV infection. 7. Need for long-term use of local or systemic steroids. 8. Patients already enrolled in other drug clinical trials. 9. Pregnant or breastfeeding women. 10. Serious systemic diseases: advanced cardiac disease, kidney disease, respiratory disease, or other malignant tumors, etc. 11. Inability to understand the research content. If both eyes of a patient meet the inclusion criteria, the right eye will be selected for participation in the study, while the left eye will receive the same treatment, but its data will not be included in this research. Each patient can have only one eye participating in the study. If both eyes of a patient meet the inclusion criteria and the patient is randomized to the ISRT group, the eye with the larger lesion or with more symptomatic disease is treated first, and in the case of well tolerability, the other eye is irradiated.