Ultra-Low Dose Radiotherapy Combined with Orelabrutinib Improves the Complete Response Rate of Treatment for Localized Ocular Adnexal Extranodal Marginal Zone B-Cell Lymphoma

Background: Extranodal marginal zone B-cell lymphoma (EMZL) is the most common lymphoma of the ocular adnexa (OA). Although radiotherapy is still the first-line treatment for localized OA-EMZL (stage I/II), the toxic effects of standard dose radiotherapy cannot be ignored. While reduced doses of radiotherapy can lessen these toxic effects, they also lower the complete response (CR) rate. We aim to use prospective trials to improve this CR rate while reducing the toxic effects of radiotherapy.

Methods: This is a single-arm, open clinical trial. Nine patients were diagnosed with OA-EMZL through surgery. These patients had Ann Arbor stage I/II with residual lesions. They received an ultra-low dose of radiation therapy, with each dose of 2 Gy administered twice, for a total of 4 Gy. Concurrently, the patients received oral orelabrutinib, 150 mg daily, every 4 weeks as a course of treatment, and the efficacy and adverse reactions were evaluated. During the treatment process, the patients continued to take oral orelabrutinib for four courses.

Results: One patient had involvement of both eyes, while the remaining eight had monocular involvement. Eight patients had lesions located in the orbit, and one had lesions in the orbit and lacrimal gland. Currently, five of the patients have completed treatment and all achieved CR, while the remaining four cases are still under treatment. Three patients achieved CR after three courses, and two patients achieved CR after four courses. Additionally, the lesions in the patients still undergoing treatment have shrunk compared to before treatment. During treatment with orelabrutinib, one patient experienced mild leukopenia and one patient experienced mild thrombocytopenia. There were no early toxic effects, such as dermatitis, xerophthalmia, conjunctivitis, watering eyes in eight patients. Moreover, dry eye was not aggravated in one patient due to lacrimal gland resection.

Conclusion: The combination of ultra-low dose radiotherapy and orelabrutinib in the treatment of OA-EMZL not only improves the effectiveness of treatment but also significantly reduces the toxic effects of radiotherapy, providing a new approach for the treatment of localized OA-EMZL.

No relevant conflicts of interest to declare.