Ocular adnexal lymphoma: clinical behavior of distinct World Health Organization classification subtypes

To evaluate the clinical behavior and treatment outcome of ocular adnexal lymphomas classified by the World Health Organization system, with emphasis on marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT).

The clinicopathologic materials from 98 consecutive patients treated for ocular adnexal lymphoma were reviewed. Fourteen patients had prior lymphoma and 84 patients had primary disease (75% Stage I, 6% Stage III, and 19% Stage IV). Radiation (photons/electrons) was administered to 102 eyes to a median dose of 30.6 Gy. The mean follow-up was 82 months.

The most common subtypes among the primary patients were MALT (57%) and follicular (18%) lymphoma. The 5-year actuarial local control rate in 102 irradiated eyes was 98%. Among the low-grade lymphomas, the 5-year local control rate correlated with the radiation dose in the MALT lymphoma subgroup (n = 53): 81% for <30 Gy and 100% for > or =30 Gy (p <0.01). For the non-MALT low-grade lymphomas such as follicular lymphoma (n = 30), the local control rate was 100% regardless of dose. For 39 Stage I MALT lymphoma patients treated with radiation alone, the distant relapse-free survival rate was 75% at 5 years and 45% at 10 years. Distant relapses were generally isolated and successfully salvaged by local therapy. The overall survival for this subgroup was 81% at 10 years, with no deaths from lymphoma.

Dose-response data suggest that the optimal radiation dose for MALT lymphoma of the ocular adnexa is 30.6-32.4 Gy in 1.8-Gy fractions and follicular lymphoma is adequately controlled with doses in the mid-20 Gy range. The substantial risk of distant relapse in Stage I ocular adnexal MALT lymphoma underscores the importance of long-term follow-up for this disease and the need for additional comparative studies of MALT lymphoma of different anatomic sites.