Outcome of patients with diffuse large B-cell lymphoma and testicular involvement - real world data

Patients with testicular lymphoma are at an increased risk of central nervous system (CNS) disease. Optimal strategy for CNS relapse prevention is unknown. We analyzed treatment strategies, cumulative incidence of CNS relapse and prognosis in 229 patients with diffuse large B-cell lymphoma (DLBCL) and testicular involvement: 157 primary testicular lymphomas (PTL) in clinical stages IE/IIE and 72 patients in advanced stages (T-DLBCL) IIIE/IV. Treatments for PTL vs. T-DLBCL included: rituximab-based chemotherapy (80.9% vs. 90.3%), orchiectomy (94.3% vs. 65.3%) and contralateral testicular irradiation (59.8% vs. 44.4%). Majority (84.3%) received CNS prophylaxis with similar rates of prophylactic methotrexate (intravenous 19.1% vs. 16.6%, intrathecal 40.8% vs. 40.4%, or both 24.2% vs. 27.8%) between PTL and T-DLBCL (p = 0.89). Median follow-up was 51.8 months. CNS relapses occurred in 14 (6.1%) of 63 relapsing patients. The 5-year cumulative incidence of CNS relapse in PTL was 4.5% and in T-DLBCL 12.1%. Median time to CNS relapse was 21.9 months. In univariate analyses, orchiectomy was the single significant factor associated with lower risk of CNS relapse in PTL (HR = 0.11 [95% CI, 0-0.124], p = 0.001). Rituximab significantly reduced CNS relapse risk in T-DLBCL (HR = 0.1002, p = 0.0005). Median progression-free survival (PFS) and overall survival (OS) following CNS relapse was dismal in T-DLBCL compared to PTL (PFS 1.6 vs. 37.8 months, p = 0.04 and OS 2.3 vs. 37.8 months, p = 0.05). This study confirmed a favorable impact of rituximab in prevention of CNS relapse in T-DLBCL. Methotrexate prophylaxis did not alter CNS relapse risk. Prognosis of CNS relapse is particularly poor in T-DLBCL.