Comparison of the (A, B, C) staging and the Rai's staging from a large prospective series (935 patients). French Cooperative Group on Chronic Lymphocytic Leukemia.

In 1979, the French Cooperative Group on Chronic Lymphocytic Leukemia proposed a 3-stage prognostic classification, called the (A, B, C) system. This staging system was used in the design of a protocol which included 973 patients from May 1980 to May 1985. The third interim analysis of this protocol, which was performed on the reference date of June 1, 1987, enabled us to compare this (A, B, C) system with the Rai's staging system, using the largest prospective series ever used. This analysis confirmed that stage A patients (n = 612) have a similar survival pattern to stage 0 patients from Rai's (n = 291) (5-year survival rate: 78% versus 82%), that the (A, B, C) staging system adds prognostic information within the Rai's stages. The (A, B, C) system appears to be an optimal tool for designing clinical trials in Chronic Lymphocytic Leukemia.