Screening of Adverse Prognostic Factors and Construction of Prognostic Index in Previously Untreated Concurrent Follicular Lymphoma and Diffuse Large B-Cell Lymphoma

Abstract

Objective. Concurrent follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) (defined as FL/DLBCL) have been considered an important pathological feature in cell lymphoma. However, clinicopathological information and prognostic factors in these cases are scarce. The aim of this study was to construct a prediction index to compare with traditional prognostic models. Methods. Retrospectively enrolled, previously untreated FL/DLBCL ( $n=121$ ) patients, as well as those with pure FL 1–3a ( $n=471$ ), were assessed. De novo DLBCL ( $n=529$ ) were used as controls. Kaplan–Meier curves were plotted to compare the outcomes among the three groups. Multivariate analysis identified risk factors associated with overall survival (OS) in FL/DLBCL patients. A clinicopathological prognosis index (CPPI) was developed to predict OS based on the Cox proportional hazards model. Results. The outcomes of FL/DLBCL patients were intermediate between pure FL 1–3a and de novo DLBCL patients, with a 5-year PFS of 70%, 59%, and 48% ( $P<0.05$ ) and 5-year OS of 80%, 70% and 60% ( $P<0.05$ ), respectively. Cox regression analysis showed that the prognostic factors of OS for FL/DLBCL patients included FL grade, cell of origin, and Ann Arbor stage. A nomogram and clinicopathological prognostic index (CPPI) were developed to predict the OS for FL/DLBCL patients based on these factors. The area under the curve (AUC) of the CPPI for 3- and 5-year OS prediction was 0.782 and 0.860, respectively. This was superior to that of the International Prognostic Index (IPI), Follicular Lymphoma International Prognostic Index (FLIPI), and FLIPI2 in the 0.540–0.819 ( $P<0.01$ ) range. Conclusions. A valid OS estimation in FL/DLBCL patients, using the recommended CPPI, may be useful in routine clinical practice.