Impact of Biological Variables on Need of Treatment in B-CLL: Study of 347 Patients in a Single Institution
Authors: Garcia-Rodriguez Mj , de Paz Raquel , Canales M. , Morado M. , Hernandez-Navarro F. 
Published: April 2020

Background: Chronic lymphocytic leukemia (CLL) has an extremely variable clinical course. Some patients have a rapid and fatal evolution, and die earlier after diagnosis, whereas others have an indolent disease, and live for 10–20 years without symptoms. Ray and Binet system have been classically considered standard clinical staging method, but have a recognised limitation to identify the real risk to start treatment in patients with initial stage of disease (Rai 0–2, Binet A).

Objetive: Our objective was to evaluate the impact of biological variables (cytogenetic analyses and CD38 and ZAP70 expression) independently of Rai and Binet stage at diagnosis, in the need of treatment. Moreover we analyzed the treatment-free survival at 12 and 60 months.

Patients and methods: Our study includes 347 patients with B-CLL, 167 men and 180 women, with a median age of 70 years (range 35–97 years) who were retrospectively analyzed. All patients were diagnosed in our center during a period of 20 years, on the basis of a clinical examination as well as morphological and immunological criteria. Chromosomal abnormalities were studied using FISH cytogenetic methodology in 79.3% of patients. Patients with normal karyotype or single abnormality of 13q-, were considered in the group of favourable prognosis. Patients with other abnormalities such as trisomy 12, 17p- and 11q-, were considered as high risk of progression. CD38 expression was analyzed by flow cytometry in 90.2% of patients. A cut-off ≥30% was defined to distinguish positive and negative expression. ZAP70 expression was studied in 64.8% and we considered positive a cut-off ≥20%.

Results: 78.9% of patients were classified by FISH in the good risk prognosis group. CD38 positive expression was detected in the 24.6% and ZAP70 was positive in the 56%. When we analysed the biological characteristics of treated patients we observed that they expressed CD38, ZAP70 and unfavourable karyotype more frequently than total population studied. These differences were more significant than the relationship with Rai and Binet stage.

At 12 months of follow-up, we found that only 21% of patients with CD38 negative expression need treatment versus 40% of patients with positive expression. 25% of patients with ZAP-70 negative expression and 35% of ZAP-70 positive expression need treatment at this moment. 27% of patients with favourable kariotype and 29% of patients with unfavourable cytogenetic were treated (Figure 1).

At 5 years since the moment of diagnostic, these differences were more significant. 82% of patients with CD38 positive expression need treatment versus 64% of patients with CD38 negative expression; 80% of patients with unfavourable cytogenetic need treatment versus 64% of patients with favourable kariotype. No differences were found in the two groups of the ZAP70 expression (Figure 1).

Conclusions: We observed that biological markers, fundamentally CD38 expression, predict need of treatment. The percentage of treated patients was significantly higher in the group of CD38 positive expression at the moment of diagnosis. The follow-up of our patients shows that the treatment-free survival is lower in patients with CD38 positive expression, so this marker could be used to predict need of treatment and separate those cases of smouldering B-CLL that no need to be observed so intensively in which the best option of treatment is “watch and wait”.

Figure 1. Treatment-free survival in 347 patients with B-CLL according to karyotype, CD38 and ZAP70 expression. Figure 1. Treatment-free survival in 347 patients with B-CLL according to karyotype, CD38 and ZAP70 expression.