Patients with a particular form of adnexal cancer called extranodal marginal zone B-cell lymphoma fared well after treatment with low-dose external beam radiation when involvement was localized. By contrast, rituximab-based chemotherapy should be considered in patients where the disease has spread. These findings come from a large cohort study just published in the British Journal of Ophthalmology.

Extranodal marginal zone B-cell lymphoma is a slow-growing tumor with an excellent long-term survival, the researchers noted.

The multicenter study included cases followed at seven international eye cancer centers from 1980 through 2017. A total of 689 patients with the lymphoma were enrolled in the study.

The majority of patients (82%) were diagnosed using either Ann Arbor staging (90%) or American Joint Committee on Cancer staging (61%). The study found the orbit and the conjunctiva were the most frequently involved anatomical structures (66% and 37%, respectively). The disease-specific survival rates at five, 10 and 20 years were 96%, 91% and 90%, respectively.

At 10 years, researchers found early-stage patients treated with external beam radiation therapy as monotherapy had a better survival rate than those treated with chemotherapy (95% vs. 86%). Additionally, later-stage patients treated with chemotherapy and rituximab had a better disease specific survival rate at 10 years (96%) than chemo patients treated without rituximab (63%).

To date, this is the largest cohort study on extranodal marginal zone B-cell lymphoma of the ocular adnexa, the researchers wrote in their paper.