Research in context
Evidence before this study
Refining prognostication of chronic lymphocytic leukaemia has become essential, as therapeutic concepts are changing from chemoimmunotherapy to targeted drugs. Provision of a more accurate, comprehensive tool to predict the heterogeneous clinical course of this cancer would be relevant both for patient counselling and designing of future clinical trials. Between Jan 1, 2009, and Dec 31, 2010, the Cochrane Haematological Malignancies Group did a systematic database search of MEDLINE, Embase, and Central for prognostic factors in chronic lymphocytic leukaemia published between Jan 1, 1950, and Dec 31, 2010, evaluating at least one of the following new prognostic factors: del(17p), del(11q), trisomy 12, del(13q), del(6q), IGHV mutational status, ZAP-70, CD38, or TP53 mutational status. Their search identified 13 eligible phase 3 clinical trials.
Added value of this study
Our meta-analysis used the individual patient data of eight trials identified in the Cochrane systematic search and two additional prospective cohorts to evaluate the currently known prognostic markers including novel gene mutations. The results allowed us to propose an easily applied prognostic model—the chronic lymphocytic leukaemia international prognostic index (CLL-IPI)—based on five widely available parameters defining four distinct groups of patients with very different prognoses.
Implications of all the available evidence
The CLL-IPI will allow uniform reporting of patients in clinical trials internationally with a classification that includes modern prognostic factors beyond clinical staging. It also prepares clinical staging of chronic lymphocytic leukaemia, for a potentially bright future of more targeted and more efficacious therapies, and will improve the precision of prognostic counselling of patients with chronic lymphocytic leukaemia regarding the implications of their disease.