Central Nervous System Progression in Primary Vitreoretinal Lymphoma with Bilateral and Unilateral Involvement: A Systematic Review and Meta-Analysis

SIMPLE SUMMARY: Primary vitreoretinal lymphoma (PVRL) is a rare disease with high mortality rates. It has a poor prognosis mainly because of its tendency to spread to the central nervous system (CNS). The optimal treatment strategy for PVRL is unknown; ideally, a treatment should prevent spread to the CNS, and thereby prolong overall survival. PVRL may occur in one eye (unilateral PVRL), or in both (bilateral). We reviewed studies from the scientific literature to investigate whether the risk of CNS progression differs between bilateral and unilateral PVRL. The quality of most available studies was moderate, at best. From the available studies, we found no difference in the development of CNS disease between patients with bilateral PVRL and unilateral PVRL. ABSTRACT: Background: Primary vitreoretinal lymphoma (PVRL) is either unilateral or bilateral at initial presentation. Progression to a central nervous system (CNS) lymphoma is regularly observed and these patients seem to have an inferior survival. Knowledge of the predictive value of laterality for CNS progression may facilitate risk stratification and the development of more effective treatment strategies, and eventually, improve outcomes. The objective of this analysis is to estimate the risk of CNS progression for patients with bilateral versus unilateral involvement of PVRL. Methods: Systematic literature search for studies on CNS progression in PVRL with bilateral and unilateral involvement according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We assessed the risk of bias and the methodological quality of studies using the Quality in Prognosis Studies (QUIPS) tool. Risk ratios of CNS progression in PVRL with bilateral and unilateral involvement were calculated and combined via a meta-analysis. Results: Twenty-five small-sized (total n = 371 cases) studies were included. The majority of the studies were at medium to high risk of bias. Results suggest no significant difference in CNS progression between bilateral and unilateral PVRL, with a pooled relative risk ratio of 1.12 (95% confidence interval 0.89–1.41). Conclusions: CNS progression is common in PVRL. From the limited available evidence, there is no significant difference in CNS progression between bilateral and unilateral PVRL.