Feasibility of the TNM-based staging system of ocular adnexal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma).

The American Joint Committee on Cancer has proposed the tumor, node, metastasis (TNM) staging system to overcome the limitations of the Ann Arbor staging system for ocular adnexal lymphoma. We performed this study to evaluate the feasibility of the TNM staging system for ocular adnexal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (OAML). The data form 66 total eyes from 54 patients with biopsy-confirmed OAML according to World Health Organization classification were retrospectively analyzed. Using the TNM staging system, we reclassified all patients into two categories: (1) T1N0M0 stage group (n = 26), for patients with lymphoma involving only the conjunctiva; and (2) above T1N0M0 or bT1N0M0 stage group (n = 28), for patients with lymphoma extending to the orbit, eyelid, or adjacent structures, and/or bilateral OAML. After a 24-month median follow-up period for all patients, the T1N0M0 group revealed higher progression-free survival (PFS) than the above T1N0M0 or the bT1N0M0 group (P = 0.041). In a separate analysis of only 50 patients categorized as Ann Arbor stage IE, the T1N0M0 group demonstrated higher PFS (100%) than the above T1N0M0 or the bT1N0M0 group (84.7%; P = 0.067). Our data show that the poor prognostic group classified as Ann Arbor stage IE can be further distinguished by using the TNM staging system. Thus, further studies to develop treatment strategies for reducing relapse after treatment for OAML should use the TNM staging system.