The utility of a prognostic index for predicting time to first treatment (TFT) in early chronic lymphocytic leukemia (CLL): the GIMEMA (Gruppo Italiano Malattie Ematologiche dell' Adulto) experience

BACKGROUND: A prognostic index based on widely available clinical and laboratory features was recently proposed to predict survival in patients with previously untreated chronic lymphocytic leukemia. We assessed the utility of this index for predicting time to first treatment in early chronic lymphocytic leukemia. DESIGN AND METHODS: An observational database of the GIMEMA (Gruppo Italiano Malattie EMatologiche dell'Adulto), which included 310 patients with newly diagnosed Binet stage A chronic lymphocytic leukemia who were observed at different primary hematology centers during the period 1991 - 2000, was used for the purpose of this study. RESULTS: The new prognostic index enabled Binet stage A patients to be divided into two subgroups that differed with respect to time to first treatment (P=0.003). The original prognostic index was derived from a database that included cases observed at a reference academic center; these patients were younger (P<0.0001) and had more advanced disease (P<0.0001) than those in the current investigation, which studied community-based patients whose data were recorded at presentation. With this in mind, we used an optimal cut-off search to determine how best to split patients with Binet stage A disease into different prognostic groups. According to the recursive partitioning (RPART) model, a classification tree was built that identified three subsets of patients who scores were 0-2 (low risk), 3-4 (intermediate risk) and 5-7 (high risk). The probability of remaining free from therapy at 5 years was 100% in the low risk group, 81.2% in the intermediate risk group and 61.3% in the high risk group (P