Real world outcomes and prognostic factors in Chinese patients with primary mediastinal B cell lymphoma: A single center experience and the Surveillance, Epidemiology, and End Results validation.

This study aimed to characterize the clinical characteristics, treatment patterns, survival outcomes, and prognostic factors of Chinese patients with primary mediastinal B-cell lymphoma (PMBCL). We retrospectively reviewed 69 consecutive patients with PMBCL treated at our center between 2010 and 2025. External validation was performed using data from the Surveillance, Epidemiology, and End Results (SEER) database (n = 1,460). The median age at diagnosis was 33 years (range, 18–62), with a female predominance (female-to-male ratio, 2.1:1). Most patients (92.8%, 64/69) received R-DA-EPOCH as frontline therapy, and 29.0% (20/69) additionally underwent consolidative radiotherapy (RT). Among 51 evaluable patients, the objective response rate was 90.2%, with a complete response rate of 74.5%. After a median follow-up of 74 months (range, 2–166), the estimated 5-year progression-free survival (PFS) and overall survival (OS) rates in whole cohort were 88.7% and 94.8%, respectively. Hematologic toxicity, predominantly febrile neutropenia, was the most common adverse event; nevertheless, 60.4% of patients maintained a relative dose intensity ≥ 100%. Consolidative RT did not confer a survival advantage, whereas age > 40 years emerged as an adverse prognostic factor for OS, a finding further validated in the SEER cohort. Chinese patients with PMBCL generally have favorable outcomes in the modern treatment era. However, older age (> 40 years) is associated with inferior survival. The R-DA-EPOCH regimen demonstrated high efficacy in this real-world setting, whereas additionally consolidative RT failed to provide a significant survival benefit.