Prognosis of localized diffuse large B-cell lymphoma in younger patients

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 < or = 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.