Montalbán, CarlosDíaz-López, AntonioMartín, AlejandroBaile, MónicaSanchez, José MSancho, Juan MGarcía, OlgaNovelli, SilvanaMonter-Rovira, AnnaSalar, AntonioBastos, MarianaGutiérrez, AntonioBento, LeyreCórdoba, RaulArquero, TeresaGonzález de Villambrosia, SoniaBarranco, GilbertoDe Oña, RaquelLópez Guillermo, ArmandoRodriguez Salazar, María JDomínguez, Juan FFernández, RubénQueizan, José ARodríguez, JoséAbraira, VictorGarcía, Juan FGELTAMO-IPI Project Investigators2023-01-252023-01-252018-07-05http://hdl.handle.net/10668/12684The Grupo Español de Linfomas y Trasplantes de Médula Ósea International Prognostic Index (GELTAMO-IPI) stratifies four risk groups in diffuse large B cell lymphoma (DLBCL) patients treated with immunochaemotherapy: low (LR), low-intermediate (LIR), high-intermediate (HIR), and high (HR). The present study explores the effect of GELTAMO-IPI in the DLBCL subtypes defined by the immunohistochaemistry-based Hans algorithm, Germinal Centre B (GCB) and non-GCB. A multivariate Cox regression model including GELTAMO-IPI risk groups, cell of origin (COO) subtypes and their product was developed to evaluate interaction between the two variables. The COO subtype was available in 839 patients (380 GCB; 459 non-GCB) and both the GELTAMO-IPI and the COO subtype in 780 (353 GCB; 427 non-GCB). There were no differences in 5-year overall survival (OS) between the two subtypes. The Cox model revealed interaction between the GELTAMO-IPI risk groups and the COO subtypes (P = 0·005), indicating that GELTAMO-IPI has a different effect in the two subtypes. Three risk groups were stratified in both COO subtypes: in the GCB subtype, LR, LIR and the combined HIR+HR had 5-year OS of 100%, 75% and 52%, respectively. In the non-GCB subtype, LR, the combined LIR+HIR and HR had a 5-year OS of, 97%, 82% and 35% respectively. GELTAMO-IPI identifies a genuine poor outcome group of patients in the DLBCL non-GCB subtype.enGELTAMO-IPIHans algorithmcell of origin subtypingdiffuse large B cell lymphomaimmunohistochemistryAdultAgedAlgorithmsAntineoplastic Combined Chemotherapy ProtocolsDisease-Free SurvivalFemaleGerminal CenterHumansImmunotherapyLymphoma, Large B-Cell, DiffuseMaleMiddle AgedPrognosisRisk AssessmentRisk FactorsSurvival Rateresearch article29978453open access10.1111/bjh.154461365-2141https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/bjh.15446