First-line treatment and survival of transformed follicular lymphoma in the netherlands in the rituximab era; a population-based analysis

Introduction: Treatment of transformed follicular lymphoma (TFL) is diverse as there are no randomized studies to guide therapy. Patients are treated with rituximab (R)-chemotherapy only or with R-chemo and upfront autologous stem cell transplantation (ASCT) at their physicians' discretion. We investigated different treatment modalities and outcome of patients registered in the Population-based Haematological Registry for Observational Studies (PHAROS), covering 40% of the Dutch population. Methods: From the PHAROS registry, we extracted all patients with a diagnosis of both follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) between January 2004 and July 2013 and checked their histology. Only patients with biopsy-proven DLBCL and underlying FL (previously or simultaneously diagnosed) were included. A separate analysis was performed on patients below 68 years, since upfront ASCT was given up to 67 years. Results: One hundred and sixty-one patients were included, median age at transformation was 63 years (34-91), median time to TFL was 14 months (0-101) and median follow-up after transformation was 17 months (1-111). Former treatment for FL: Sixty-one per cent had been treated with chemotherapy for FL (66% of them with R), 2% had received radiotherapy only, 24% were under a watch-and-wait strategy and, in 13%, FL and DLBCL were diagnosed simultaneously. Treatment for TFL: Ten patients were unable to receive any treatment. All 151 treated patients received R-chemo as induction therapy: 62 patients (33,