Good Predictive Value of Combined Cytogenetic and Molecular Follow Up in Chronic Myelogenous Leukemia After Non T-cell Depleted Allogeneic Bone Marrow Transplantation: A Report on 38 Consecutive Cases

Abstract

We prospectively performed repeated cytogenetic and PCR monitoring of residual disease in all cases Ph positive of chronic myeloid leukemia (CML) allografted with non T cell depleted marrow at our institution over a period of 8 years. Thirty eight patients who survived the immediate post transplant period could be analyzed (median of 3 cytogenetic analyses/patient. examining 100 mitoses, and 4 PCR analyses/patient). Seven of the 38 patients had a hematological relapse (which was extramedullary in one case) and one a purely cytogenetic relapse, possibly stabilised by interferon treatment. Within 6 months of transplant, Ph positive mitoses were seen in 2 patients, and positive F'CR in most cases, without implying subsequent relapse. Six of the 32 patients analyzed cytogenetically more than 6 months post transplant had Ph positive mitoses on at least one occasion: 5 had a hematological relapse within 7 months of positive cytogenetic analysis, and the remaining patient, treated by interferon remained in purely cytogenetic relapse. (The extramedullary relapse was not preceded by a positive marrow karyotype).

Eight of the 38 patients had positive PCR findings on at least one occasion more than 6 months post transplant. Seven relapsed (6 hematological relapses including the extramedullary relapse, and 1 cytogenetic relapse) after 3 to 20 months, but the remaining patient remained in CR 36 months later, with negative PCR. The 30 patients who never had positive PCR findings remained in CR. In this relatively large series of patients, we found a good correlation between PCR findings more than 6 months post transplant and remission or relapse status. Cytogenetic follow up was useful in the presence of positive PCR results, as positive cytogenetic findings in this situation indicated imminent hematological relapse, justifying rapid therapeutic intervention in order to prevent it.

Key Words:

• Predictive Value
• Cytogenetics
• Molecular follow up
• Bone marrow transplantation
• Chronic myelogenous leukemia