FCR (fludarabine, cyclophosphamide, rituximab) combination is currently accepted as the gold standard in treatment of younger and physically fit CLL patients. These excellent results, however, cannot be generally applied to the whole CLL population. This is because the median age at diagnosis of CLL lies between 65 and 72 years and patients older than 65 years in fact account up to 50%-75 % of the CLL population. Nevertheless, such population is considerably underrepresented in most of the large clinical trials in CLL/SLL. Therefore, it is not clear whether elderly/comorbid patients could profit from newer treatment approaches such as purine analog combinations or chemoimmunotherapy. Several publications demonstrated unacceptable toxicity of full-dose FC/FCR in elderly CLL patients. However, regimens using attenuated doses of fludarabine and cyclophosphamide showed promising efficacy and low toxicity.

The objective of this observational study is to provide additional data to confirm the safety profile and efficacy of low dose FCR for CLL patients treated in clinical practice.

Specific data of interest are: comorbid concitions, concomitant medication, CLL characteristics, prior treatment regimens, adverse events, reasons for discontinuation low dose FCR, overal response rates, complete response rate, progression-free survival, overall survival.

This is an observational, non-interventional, medical record review study in CLL patients. A total of 200 patients with CLL who have been previously treated with low dose FCR will be eligible for the study.

Inclusion Criteria:

• confirmed diagnosis of CLL or SLL
• previously treated by low dose FCR for active disease requiring treatment per IWCLL criteria
• dose reduction of fludarabine and cyclophosphamide due to age, comorbid conditions, or reduce creatinine clearance

Exclusion Criteria:

• patients treated with low dose FCR within prospective clinical trials

Patients with CLL or SLL deemed unfit for full-dose FCR. Both untreated and relapsed/refractory setting.