[Significance of Minimal Residual Disease in Chronic Lymphocytic Leukemia]

Newly introduced highly effective treatment options increase the importance of minimal residual disease measurement in chronic lymphocytic leukemia. Minimal residual disease is gaining interest mainly as a predictive marker; however, clinical significance of minimal residual dis-ease in chronic lymphocytic leukemia in many different situations remains unresolved. Factors with a possible impact on the clinical significance of minimal residual disease are as follows: technique for minimal residual disease quantification, treatment regimen, peripheral blood vs. bone marrow analysis or time -point for sampling. Highly sensitive methods now available to evaluate minimal residual disease can detect a single chronic lymphocytic leukemia cell in 10(-4)- 10(-5) leukocytes using either allele -specific oligonucleotide polymerase chain reaction or multicolor flow cytometry. Minimal residual disease quantification as a surrogate marker to assess treatment efficacy in routine hematological practice has to be further evaluated.