Natural history of early chronic lymphocytic leukemia. A single institution study with emphasis on the impact of disease progression on overall survival

Background and Objectives. Criteria for identifying patients with early chr onic lymphocytic leukemia (CLL) who are likely to progress to a more advanc ed clinical stage rely on results of prospective clinical trials. Is not cl ear whether these same criteria apply to patients followed-up in the settin g of clinical practice. With the aim of addressing this issue we investigat ed the clinical outcome of a series of patients with Binet stage A CLL. Design and Methods. Two hundred and four Binet stage A CLL patients observe d at a single institution over an 18-year period form the basis of this stu dy. Different proposals for subclassifying Binet stage A were validated by using our patients as test-set cases. Results. The survival of patients with early CLL (i.e., Binet stage A and R ai stage 0) was significantly different from that of an age- and sex-matche d population. Three of 4 different criteria for subclassifying stage A (Rai substaging, Montserrat criteria, French Group proposal), when applied to o ur patients, gave similar results in terms of sample size, death rate and d isease progression (DP) risk. The French Group proposal, based exclusively on blood counts and hemoglobin levels, was not effective in predicting the risk of DP. Forty-nine (23.5%) patients progressed to a more advanced clini cal stage (30 to stage B and 19 to stage C); the risk of DP was 32.8% at 5 years and 49.6% at 10 years, When analyzed as a time-dependent variable (Ma ntel-Byar method), DP had a clear cut-impact on overall survival (p < 0.000 1). Finally, outlook for survival of patients who experienced a change of c linical stage was similar to that of patients in that stage at the time of diagnosis. Interpretation and Conclusions. As many patients are now being diagnosed wh ile asymptomatic and at a younger age than previously, an accurate evaluati on of prognosis is mandatory in early CLL. How prognostic information trans lates into a policy of early or delayed therapy is still unclear. Our resul ts further support a conservative approach for CLL in early stage; patients who progress into a more advanced stage have similar survival to those in that stage at diagnosis. (C) 1999, Ferrata Storti Foundation.