MONITORING RESIDUAL DISEASE IN ACUTE LYMPHOBLASTIC-LEUKEMIA - THERAPEUTIC IMPLICATIONS

The polymerase chain reaction (PCR) has been applied to detect occult leukemia (ALL) cells in patients with acute lymphoblastic leukemia who are otherwise considered in complete remission by traditional morphol ogical examination of bone marrow specimens. The combined data from th e clinical studies published to date suggest that a consistent pattern for residual disease disappearance over many months exists for patien ts who remain in complete remission for an extended period of time. Co nversely, a pattern of residual disease persistence and reappearance p receding clinical findings exists for the majority of patients who ult imately relapse. The ability to detect residual ALL disease near the e nd of chemotherapy or after the completion of treatment in some patien ts who otherwise are deemed likely to be cured of their malignancy rai ses the possibility that mechanisms other than leukemia cell cytotoxic ity are influencing the outcome for this disease.