Long-term outcomes of patients with conjunctival extranodal marginal zone lymphoma

Comprehensive information on clinical features and long-term outcomes of primary conjunctival extranodal marginal zone lymphoma (PCEMZL) is scarce. We present a large single-institution retrospective study of 72 patients. The median age was 64 years, and 63.9% were female. Stage I was present in 87.5%. Radiation therapy (RT) alone was the most common treatment (70.8%). Complete response (CR) was 87.5%, and 100% in RT-treated patients. With a median follow-up of 6.7 years, relapse/progression and death occurred in 19.4% each, with one relapse within the RT field. The 10-year progression-free survival (PFS) and overall survival (OS) were 68.4% (95% CI 52.8%-79.8%) and 89.4% (95% CI 77.4%-95.2%), respectively. The 10-year rate for time to progression from diagnosis was 22.5% (95% CI 11.6%-35.7%). The 10-year PFS and OS of MALT-IPI 0 versus 1-2 were 83.3% versus 51.3%, (p = .022) and 97.6% versus 76.6%, (p = .0052), respectively. The following characteristics were associated with shorter survival: age > 60 years (PFS: HR = 2.93, 95% CI 1.08-7.95; p = .035, OS: HR = 9.07, 95% CI 1.17-70.26; p = .035) and MALT-IPI 1-2 (PFS: HR = 2.67, 95% CI 1.12-6.31; p = .027, OS: HR = 6.64, 95% CI 1.45-30.37; p = .015). CR following frontline therapy was associated with longer PFS (HR = 0.13, 95% CI 0.04-0.45; p = .001), but not OS. Using the Fine and Gray regression model with death without relapse/progression as a competing risk, RT and CR after frontline therapy were associated with lower risk of relapse (SHR = 0.34, 95% CI 0.12-0.96 p = .041 and SHR = 0.11, 95% CI 0.03-0.36; p < .001, respectively). Patients with PCEMZL treated with frontline RT exhibit excellent long-term survival, and the MALT-IPI score appropriately identifies patients at risk for treatment failure.