Long-term clinical outcomes of patients with localized primary ocular adnexal mucosa-associated lymphoid tissue lymphoma.

Because primary ocular adnexal mucosa-associated lymphoid tissue lymphoma (POAML) is rare, key clinical questions, including the best treatment strategy and the validity of watchful waiting (WW), remain unresolved. Although radiotherapy (RT) is the standard treatment for localized POAML, it is commonly associated with acute and late toxicities. Overall, 128 patients with localized POAML diagnosed and managed at our institution between 1998 and 2015 were retrospectively analyzed. Forty-two patients were initially managed with WW, and 86 received immediate RT. During a median follow-up of 7.2 years (range 0.1-18.4), no patients died of lymphoma progression. Seven patients in the WW group experienced disease progression at the primary site. In the RT group, almost all patients (97.7%) achieved a complete response after RT; however, 12 patients relapsed. Histological transformation occurred in one patient in each group. The 10-year cumulative incidence of progression was 24.9% (95% CI, 12.6-45.7%) with WW and 13.1% (95% CI, 6.9-23.9%) with RT (p = 0.27). The rate of freedom from systemic therapy at 10 years was 89.7 and 94.8%, respectively (p = 0.67). This observational study suggests that WW is an acceptable treatment option for selected patients with localized POAML, with no significant differences in long-term outcomes compared with RT.