Clinical features of extranodal marginal zone B-cell lymphoma

This is the largest cohort study characterizing extranodal marginal zone B-cell lymphoma (EMZL) occurring in the ocular adnexa (OA).

Study design

This retrospective study included 689 patients with OA-EMZL at 7 international eye cancer centers. Data was collected from 1980 to 2017.

Outcomes

Approximately 82% of patients were diagnosed with primary disease, 10% had disseminated disease with ocular adnexal involvement and 8% had ocular adnexal relapse of systemic disease. The most common sites of involvement were the orbit (66%) and conjunctiva (37%); only 1 patient had intraocular involvement. Approximately 85% of lesions were unilateral.

External beam radiation therapy (EBRT) as a monotherapy was the most common treatment among patients with primary disease (72%). The 5-, 10- and 20-year disease-specific survivals (DSS) were 96%, 91% and 90%, respectively. Stage IE patients had a better 10-year DSS with EBRT than with chemotherapy (95% vs. 86%). Meanwhile, stage IIE/IVE had a better 10-year DSS with rituximab-based chemotherapy than chemotherapy without rituximab (96% vs. 63%). Secondary disease and relapse or disease progression of OA lymphomas correlated with poorer outcomes.

Limitations

This study was a retrospective review of pooled cases. There were no standard protocols for treatment or follow-up.

Clinical significance

This is a large study of a relatively rare condition. It showed that EMZL is an indolent tumor with good long-term survival. Findings suggest secondary disease and relapse or OA lymphoma progression may predict poorer outcome. While low-dose EBRT may be an effective monotherapy for localized disease, rituximab-based chemotherapy could be useful for patients with disseminated disease.