The 'Real World' Uptake and Prognostic Impact of GELF in Newly Diagnosed Follicular Lymphoma: An Australasian Alliance Initiative.

Background The time to treatment initiation is determined by tumour burden in patients with follicular lymphoma (FL). The Groupe d'Etude des Lymphomes Folliculaires ('GELF') criteria, defined in the pre-rituximab era, are commonly used to assess tumour burden.2 Patients must meet >=1 of the following criteria to be considered "high" tumour burden according to GELF: any tumour mass >7 cm; >= 3 nodal sites (each >3 cm); B symptoms; splenomegaly; compression syndrome; pleural/peritoneal effusion; leukemic phase or cytopenias. Low tumour burden FL is often excluded from clinical trials, based on data from initial retrospective studies and later randomised trials, demonstrating no survival advantage with chemotherapy compared with observation alone. 1-3 Conversely, it is recommended those with high burden disease receive immediate therapy. The use of GELF in therapeutic decision-making outside of clinical trials is not well described. Methods Cases of newly diagnosed Grade 1-3a FL were retrospectively identified from the Australian Lymphoma and Related Diseases Registry (LaRDR), and 2 additional institutional databases from 2002-2019. Additional data was obtained from electronic hospital records. The primary aim of the study was to determine the utilisation of GELF criteria in guiding therapeutic decisions in FL. The secondary aims were to document frequency of GELF according to stage and treatment and to determine the impact of the number of GELF criteria on PFS. Survival analysis was calculated according to the Kaplan-Meier method. Results 385 cases were identified. Patient characteristics are in table 1. The median follow-up was 2 years (range 0.1-18) with 2-year PFS and OS of 89% (95% CI 85-92%) and 96% (95% CI 92-98%) respectively. 94 (24%) patients underwent a 'watch and wait' approach (W&W), 54 (14%) received radiotherapy alone and 237 (62%) received chemotherapy +/- radiotherapy. 118 (31%) patients had stage I/II disease at diagnosis, of these 36 (30%) underwent