Peripheral blood vs. bone marrow for molecular monitoring of BCR-ABL1 levels in chronic myelogenous leukemia, a retrospective analysis in allogeneic bone marrow recipients.

Molecular monitoring of the BCR-ABL1 transcript in chronic myelogenous leukemia (CML) using quantitative real-time PCR (RQ-PCR) can be performed using either bone marrow (BM) or peripheral blood (PB). However, a recent report by Stock et al. [International Journal of Oncology 28 (2006) 1099] questioned the reliability of PB samples for BCR-ABL1 detection as performed by RQ-PCR. We report a study on 114 CML patients who received allogeneic stem cell transplantation (ASCT), and who were monitored by RQ-PCR using paired samples of BM and PB: the total number of determinations was 428, with a median follow-up after transplant of 8 years. BCR-ABL1 transcript was undetectable or <0.1%, in 106 (49.57%) and 62 (29%) paired determinations, respectively. BCR-ABL1 was >0.1% in 36 (16.8%) paired determinations and was discordant in 10 (4.7%). Agreement between PB and BM results was quantified by the kappa test (k = 0.85; 95% CI 0.76-0.94). This study shows that BCR-ABL1 RQ-PCR monitoring of CML patients after ASCT with PB is concordant with BM in 95.3% of cases, and thus may be used to monitor the disease. This may be relevant when discussing both quality of life issues and the need for post-transplant monitoring with the patient.