As the above-mentioned cellular and molecular parameters and newly identified biologic features are evaluated in larger numbers of patients with aggressive NHL, the biologic heterogeneity of this disease will be better appreciated. With a more complete understanding of the disease, it is likely that we will substitute biologic variables for clinical surrogate features in our prognostic factor models and target these biologic variables for therapy in specific subsets of patients. In the meantime, widely accepted clinical models such as the International Index and the age-adjusted index will aid in the identification of specific patient risk groups and the ongoing comparison of different therapeutic approaches. Early restaging with sensitive techniques like Ga-67 citrate scans may also identify patients with suboptimal responses to induction therapy at timepoints when additional therapeutic alternatives may be most effective.