Time trends in primary therapy and relative survival of diffuse large B-cell lymphoma by stage: a nationwide, population-based study in the Netherlands, 1989-2018.

It is unclear whether survival in diffuse large B-cell lymphoma (DLBCL) continues to increase in an era where rituximab-containing chemotherapy reigns for almost two decades. Therefore, we evaluated trends in primary therapy and relative survival (RS) among Dutch DLBCL patients diagnosed between 1989 and 2018. Analyses were performed separately according to the stage I (N = 6952) and stage II-IV disease (N = 20,676), stratified by calendar period and age (18-64, 65-74, and ≥75 years). The use of chemotherapy ± radiotherapy increased over time across all age and stage groups. As of the mid-2000s, >95% of chemotherapy-treated patients received chemoimmunotherapy, irrespective of age and stage. Overall, RS increased significantly over time across all age groups, especially after 2003 when rituximab-containing chemotherapy had become the standard of care. However, RS increased less pronounced between 2003-2010 and 2011-2018 than between 1989-2002 and 2003-2010. These findings were congruent across all studied stage groups. Five-year RS across the three age groups during 2011-2018 was 96%, 84%, and 67% for stage I DLBCL and 75%, 60%, and 46% for stage II-IV DLBCL. Collectively, survival in DLBCL increased modestly beyond the initial introduction of rituximab, with apparent survival differences across age and stage that warrant novel treatment approaches.