Post-treatment residual masses in orbital lymphoma: incidence, risk factors, and prognostic impact.

Abstract

Purpose: We aimed to evaluate the incidence and risk factors for residual masses (RMs) following first-line treatment of primary orbital lymphoma (OL) and identify predictors of local recurrence (LR) and systemic relapse (SR) among patients with RMs.

Methods: This retrospective study included 100 individuals with OL who received treatment and were followed for over 6 months. Clinical characteristics were reviewed, and treatment responses were assessed at 12 and 24 weeks post-treatment and at the last follow-up. Risk factors for RM presence, persistence, LR, and SR were analysed.

Results: The mean age was 57.1 years, with a male predominance (61%) and a median follow-up of 58.2 months. Histological subtypes included extranodal marginal zone lymphoma (EMZL, n = 85), diffuse large B-cell lymphoma (DLBCL, n = 12), and mantle cell lymphoma (MCL, n = 3). Residual masses were identified in 73% of participants at 12 weeks post-treatment. Residual mass presence was significantly associated with tumour size ≥25 mm, AJCC N1/M1 stage, and location in the posterior orbit or with extraocular muscle involvement (each P < 0.05). All LR (n = 19) and SR (n = 8) cases occurred exclusively in patients with RMs. Local recurrence was significantly associated with N1 disease (P < 0.001), while SR correlated with high-grade histological subtypes, such as DLBCL and MCL (P = 0.026).

Conclusion: Post-treatment RMs were common in OL, particularly among individuals with advanced-stage, large, or posteriorly located tumours. Among those with RMs, AJCC N1 stage and high-grade histology were independent predictors of relapse. Given the risk of relapse despite standard first-line therapy, intensified treatment and closer surveillance should be considered in this high-risk subgroup.