Progression-Free Survival Improvement of Localized Ocular Adnexal MALT Lymphoma Patients with Residual Lesions: Comparative Outcome of Postoperative Treatment Versus Watchful Waiting

Background: Ocular adnexal extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (OA-EMZL) is a rare form of indolent non-Hodgkin's lymphoma. The frontline therapeutic modalities for localized patients involve watchful waiting or further treatment after surgery. However, it remains unclear which patient characteristics should prompt postoperative treatment.

Methods: A retrospective cohort study was conducted in a single institution, and 77 patients with newly diagnosed primary localized OA-EMZL were enrolled. We compared progression-free survival (PFS) in patients undergoing watchful waiting versus those receiving treatment after surgery. Based on the surgical method, patients were classified into a complete resection group and an incomplete resection group. PFS of patients receiving treatment and watchful waiting in different groups were compared.

Results: The median age was 59, with a male predominance (male : female = 1.45:1). The orbit (58, 75.32%) and the conjunctiva (10, 12.99%) were the most frequently involved anatomical structures. Of the 77 patients, 39 underwent watchful waiting, whereas 38 received further treatment, including localized radiotherapy, immunotherapy, or immunochemotherapy. The 5-year PFS for patients who received treatment or watchful waiting were 91.68% and 69.46%, respectively (P = 0.036). Regarding surgical methods, 21 patients underwent complete resection of the neoplasm, whereas 56 had residual lesions after surgery. In the complete resection group, 15 out of 21 and 6 out of 21 patients received watchful waiting and treatment, respectively. The 5-year PFS were 85.71% and 100%, respectively (P = 0.342). In the incomplete resection group, 24 out of 56 patients received further treatment. They had longer PFS (5-year PFS, 90.28%) compared with patients who underwent watchful waiting (5-year PFS, 62.22%) (P = 0.041). Treatment choice of radiotherapy or immunochemotherapy was not associated with PFS (P = 0.601). Of the 77 patients, ten relapsed, of which 8 had undergone watchful waiting. Seven out of eight patients had recurrence at the primary site, and one patient had distant recurrence, subsequently converting to DLBCL.

Conclusions: Overall, postoperative treatment is needed for primary localized OA-EMZL patients with residual lesions. Both radiotherapy and chemotherapy can be alternatives.

No relevant conflicts of interest to declare.