Simplicity at the cost of predictive accuracy in diffuse large B‐cell lymphoma: a critical assessment of the R‐IPI, IPI, and NCCN‐IPI

The international prognostic index (IPI) and similar models form the cornerstone of clinical assessment in newly diagnosed diffuse large B‐cell lymphoma (DLBCL). While being simple and convenient to use, their inadequate use of the available clinical data is a major weakness. In this study, we compared performance of the International Prognostic Index (IPI) and its variations (R‐IPI and NCCN‐IPI) to a Cox proportional hazards (CPH) model using the same covariates in nondichotomized form. All models were tested in 4863 newly diagnosed DLBCL patients from population‐based Nordic registers. The CPH model led to a substantial increase in predictive accuracy as compared to conventional prognostic scores when evaluated by the area under the curve and other relevant tests. Furthermore, the generation of patient‐specific survival curves rather than assigning patients to one of few predefined risk groups is a relevant step toward personalized management and treatment. A test‐version is available on lymphomapredictor.org.