Changes in the incidence, pattern of presentation and clinical outcome of early chronic lymphocytic leukemia patients using the 2008 International Workshop on CLL guidelines

Abstract

Objectives: Before 2008, diagnosis of chronic lymphocytic leukemia (CLL) relied on 1996 National Cancer Institute Working Group criteria which required an absolute lymphocyte count of 5.0 × 109/l or higher. The up-dated 2008 International Workshop on CLL (IWCLL) guidelines recommend using the B-cell count as a basis for the diagnosis of CLL and indicate a B-cell threshold of 5.0 × 109/l. The objective of this study was to assess the effects of these changes on the pattern of presentation and clinical outcome of early CLL. Methods: For this purpose we analysed 414 patients with previously untreated, Binet stage A CLL diagnosed between January 2006 and December 2010 and registered prospectively at a national database. Results: After patients were reclassified according to updated 2008 IWCLL guidelines, 130 Rai stage 0 CLL patients were reclassifed as clinical monoclonal B-cell lymphocytosis, resulting in a 31.4% decrease (from 414 to 284) in the diagnosis of early stage CLL. Moreover, a shift towards a more advanced Rai clinical stage under 2008 IWCLL criteria was observed. Finally, the estimated 3-year time to first treatment decreased from 77.2 to 69.9% according to whether 1996 National Cancer Institute Working Group criteria or 2008 IWCLL criteria were used. Conclusion: In conclusion, the 2008 IWCLL guidelines modify the distribution of Rai stage at diagnosis and shorten the time to first treatment in early CLL patients. We expect that these changes might be considered in the interpretation of epidemiologic studies in CLL and in designing clinical trials of early therapeutic intervention in patients with asymptomatic CLL.