Prognostic impact of central nervous system prophylaxis and a simplified BL model in primary testicular lymphoma: a real-world multicenter study

Primary testicular lymphoma (PTL) is a rare but aggressive form of extranodal lymphoma with a high risk of central nervous system (CNS) relapse and poor long-term survival. However, the optimal CNS prophylaxis strategy and effective prognostic models for PTL remain unclear. This study aimed to evaluate the prognostic impact of intrathecal (IT) prophylaxis and to develop a novel, simplified prognostic model in a Chinese multicenter cohort.

We retrospectively collected data from a total of 55 patients with PTL, treated at three major tertiary hospitals in China. Multivariate Cox regression identified independent prognostic factors for overall survival (OS) and progression-free survival (PFS). A new risk stratification model (BL model, based on B symptoms and LDH levels) was constructed and validated using time-dependent C-index and calibration plots, and compared with the International Prognostic Index (IPI).

IT prophylaxis reduced CNS relapse rates (9.1% vs. 36.4%, p < 0.001) and was independently associated with improved OS (HR = 0.18, p < 0.001) and PFS (HR = 0.21, p < 0.001). The BL model (B symptoms and LDH), demonstrated superior predictive accuracy compared to the IPI, with higher AUCs at 1-, 3-, and 5-year OS (0.883, 0.894, 0.854 vs. 0.656, 0.804, 0.724), and a corrected C-index of 0.798. Calibration analysis confirmed good agreement between predicted and observed survival.

IT prophylaxis significantly improves survival and reduces CNS relapse in PTL. The BL model provides a simple yet effective tool for individualized risk stratification, outperforming IPI and aiding clinical decision-making in PTL.