Stage-specific trends in primary therapy and survival in follicular lymphoma: a nationwide population-based analysis in the Netherlands, 1989-2016.

We assessed stage-specific trends in primary therapy and relative survival among adult follicular lymphoma (FL) patients diagnosed in the Netherlands between 1989-2016 (N = 12,372; median age, 62 years; and 21% stage I disease). Patients were stratified by disease stage and subsequently categorized into four calendar periods (1989-1995, 1996-2002, 2003-2008, and 2009-2016) and three age groups (18-60, 61-70, and >70 years). The use of radiotherapy in stage I FL remained relatively stable over time and across the three age groups (i.e., 66%, 54%, and 49% in 2009-2016, respectively). In stage II-IV FL, the start of chemotherapy within 12 months post-diagnosis decreased over time, indicating a broader application of a watch-and-wait approach. Relative survival improved considerably over time, especially since 2003 when rituximab was introduced in the Netherlands, and for stage III-IV FL patients and older age groups. Five-year relative survival for patients with stage I-II versus stage III-IV FL in the period 2009-2016 was 96% versus 90%, 93% versus 83%, and 92% versus 68% across the three age groups, respectively. Collectively, the improvement in survival since 2003 is accounted for by advances in FL management, particularly the implementation of rituximab. There remains, however, room for improvement among elderly stage III-IV FL patients.