RELINF: prospective epidemiological registry of lymphoid neoplasms in Spain. A project from the GELTAMO group.

Lymphomas are a large, heterogeneous group of neoplasms with well-defined characteristics, and this heterogeneity highlights the importance of epidemiological data. Knowledge of local epidemiology is essential to optimise resources, design clinical trials, and identify minority entities. Given there are few published epidemiological data on lymphoma in Spain, the Spanish Lymphoma and Autologous Bone Marrow Transplant Group created the RELINF project. The aim of this project is to determine the frequencies and distribution of lymphoid neoplasms in Spain and to analyse survival. We developed an online platform for the prospective collection of data on newly diagnosed cases of lymphoma in Spain between January 2014 and July 2018; 11,400 patients were registered. Diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL) were the most frequent lymphomas in our series. Marginal B cell lymphoma frequency was higher than that reported in other studies, representing more than 11% of mature B cell lymphomas. Peripheral T cell lymphoma not otherwise specified (PTCL-NOS) was the most common subtype of T cell lymphoma, and NK/T cell lymphomas were more frequent than expected (5.4% of total). Hodgkin's lymphoma accounted for 12% of lymphoproliferative syndromes. Overall survival was greater than 90% at 2 years for indolent B cell lymphomas, and approximately 60% for DLBCL, somewhat lower than that previously reported. Survival was poor for PTCL-NOS and angioimmunoblastic T cell lymphoma, as expected; however, it was somewhat better than that in other studies for anaplastic large cell anaplastic lymphoma kinase lymphomas. This is the first prospective registry to report the frequencies, distribution, and survival of lymphomas in Spain. The frequencies and survival data we report here are globally consistent with that reported in other Western countries. These updated frequencies and survival statistics are necessary for developing appropriate management strategies for neoplasias in the Spanish population.