Table 1. International Prognostic Index for Chronic Lymphocytic Leukemia (CLL, CLL-IPI*).

Variable	Risk factor	Points		Score	Risk group	5-year survival rates (%)	Subgroup frequency (%)
TP53 (17p)	Deletion and/or mutation	4		0–1	low	93.2	28
IGHV	unmutated	2		2–3	intermediate	79.3	39
B2M (mg/L)	>3.5	2		4–6	high	63.3	28
Age	>65 years	1		7–10	very high	23.3	5
Stage	Binet B/C, Rai I–IV	1
Total risk score		0–10

* For the variables listed in the Table, differently weighted points are awarded, resulting in total risk scores between 0 and 10.

From the total risk score, 4 risk groups can be identified (low, intermediate, high, and very high) which differ in their overall survival rates.

The classification of the risk groups originates from the time before the introduction of chemoimmunotherapy. Nevertheless, it has proven to be useful until today.

The introduction of new substances has significantly improved prognosis.

Binet or Rai staging system: disease progression is defined based on laboratory tests and physical examination;

IPI, International Prognostic Index, B2M, ß₂ -microglobulin.