A prognostic algorithm including a modified version of MD Anderson Cancer Center (MDACC) score predicts time to first treatment of patients with clinical monoclonal lymphocytosis (cMBL)/Rai stage 0 chronic lymphocytic leukemia (CLL).

We propose an algorithm based on a slightly modified version of MD Anderson Cancer Center (MDACC) score (i.e., mutational status of IgVH, LDH, presence of high-risk FISH abnormalities), β2-microglobulin and separation of clinical monoclonal B-cell lymphocytosis (cMBL) from chronic lymphocytic leukemia (CLL) to predict time to first treatment (TTFT) of a prospective multicentre cohort including 83 cMBL and 136 CLL Rai stage 0 patients. Patients with MDACC score point ≥38, at any level of β2-microglobulin and irrespective of whether they fulfilled 2008 International Workshop on CLL (IWCLL) criteria for CLL Rai stage 0 or cMBL, experienced the worst clinical outcome (5-year TTFT, 24%) and formed the high-risk group. In contrast, subjects with a diagnosis of cMBL, MDACC score point <38 and β2-microglobulin ≤ UNL had the best clinical outcome (5-year TTFT, 100%) and constituted the low-risk group. The intermediate group included patients in Rai stage 0, MDACC score point <38, and any level of β2-microglobulin, and patients with cMBL, MDACC score point <38, and β2-microglobulin ≥ UNL. Cases showing these features can be grouped together to form the intermediate-risk group (5-year TTFT, 65%). Although the separation between cMBL and Rai stage 0, as proposed by the 2008 IWCLL guidelines, has clinical implications, the model we propose may help to classify patients with cMBL and Rai stage 0 into more precise subgroups suggesting that a prognostic separation of these entities based solely on clonal B-cell threshold may be unsatisfactory.