The utility of the chronic lymphocytic leukemia - international prognostic index (CLL-IPI) in predicting outcomes of individuals with Rai 0 stage CLL and monoclonal B-cell lymphocytosis (MBL) is unclear. We identified 969 individuals (415 MBL and 554 Rai 0 CLL; median age=64 years, 65% men) seen at Mayo Clinic between 1/1/2001 and 10/1/2018, and ascertained time to first therapy (TTFT) and overall survival (OS). After a median follow up of 7 years, the risk of disease progression needing therapy was 2.9%/year for MBL (median=not reached) and 5%/year for Rai 0 CLL (median=10.4 years). Among patients with low, intermediate and high/very high risk CLL-IPI risk groups, the estimated 5-year risk of TTFT was 13.5%, 30%, and 58%, respectively, p<0.0001 (c-statistic=0.69); and the estimated 5-year OS was 96.3%, 91.5%, and 76%, respectively, p<0.0001 (c-statistic:0.65). In a multivariable analysis of absolute B-cell count with individual factors of the CLL-IPI, the absolute B-cell count was associated with shorter TTFT (hazard ratio [HR] for each 10 x 109/L increase: 1.31; p<0.0001), and shorter OS (HR: 1.1; p=0.02). The OS of the entire cohort was similar to age- and sex-matched general population of Minnesota (p=0.17), although Rai 0 CLL patients with high and very high risk CLL-IPI score had significantly shorter OS (p=0.01, and p=0.0001, respectively). The results of this study demonstrate the ability of CLL-IPI to predict time from diagnosis to first treatment (an endpoint not impacted by therapy) in a large cohort of patients whose only manifestation of disease is a circulating clonal lymphocyte population.
Sameer A Parikh, Kari G Rabe, Neil E Kay, Timothy G Call, Wei Ding, Jose F Leis, Saad S Kenderian, Eli Muchtar, Yucai Wang, Amber Koehler, Susan M Schwager, Connie Lesnick, Geffen Kleinstern, Daniel L Van Dyke, Curtis A Hanson, Esteban Braggio, Susan L Slager, Tait D Shanafelt