PFS of CLL Binet stage A patients in relation to different prognostic parameters: (A) s-TK, with a cut-off level of 7.1 U/L; (B) peripheral blood leukocyte count with a cut-off level of 75,000/μL; (C) presence or absence of lymphadenopathy. Differences were statistically significant (P < .001) for all three parameters.