Abstract
BACKGROUND
The International Prognostic Index (IPI) is widely used as a predictive model in diffuse large B‐cell lymphoma (DLBCL) patients of all ages and stages. To determine the optimal IPI‐based prognostic system at the time of diagnosis in younger patients with limited‐stage DLBCL, the authors evaluated the age‐adjusted IPI and the recently proposed stage‐adjusted IPI, and constructed an IPI‐based model adjusted for both age and stage.
METHODS
From the population‐based LYFO registry of the Danish Lymphoma Group, 233 patients not older than 60 years with Stage I‐II DLBCL treated with anthracycline‐based chemotherapy with or without involved‐field irradiation were identified. The primary endpoint of analysis was overall survival.
RESULTS
At the end of the observation period, 151 patients were alive with a median follow‐up time of 8.3 years. All the variables in the age‐adjusted and the stage‐adjusted IPI had major prognostic significance (P ≤ 0.0001). Log‐rank analyses of survival showed highly significant differences between the subgroups in each model (P < 0.0001); however, the stage‐adjusted IPI was more powerful (chi‐square test = 44.99) than the age‐adjusted IPI (chi‐square test = 36.27). By using the median age of the cohort (50 years) as a cutoff point, age was found to be a strong prognostic factor (P = 0.0036). An age‐/stage‐adjusted IPI was constructed, the predictive power of which was equal to the stage‐adjusted IPI (chi‐square test = 44.16) but with different distribution of patients between the risk groups, making the proposed model better suited to identify poor‐risk patients.
CONCLUSIONS
The data from the current study suggest that the proposed age‐/stage‐adjusted IPI is the superior IPI‐based model in predicting outcome in younger patients with localized DLBCL. Cancer 2003;98:516–21. © 2003 American Cancer Society.
DOI 10.1002/cncr.11497