Evaluation of minimal residual disease using reverse-transcription polymerase chain reaction in t(8;21) acute myeloid leukemia: A multicenter study of 51 patients

Purpose: Most studies using various reverse transcription polymerase chain reaction (RT-PCR) techniques reported that the detection of the AML1-ETO fu sion transcript was a common finding in long-term complete remission (CR) i n acute myeloid leukemia (AML) with t(8;21) translocation, However, larger prospective studies with interlaboratory quality control may be important t o investigate more precisely the clinical usefulness of studying minimal re sidual disease with RT-PCR in t(8;21) AML. Patients and Methods: We collected 223 marrow samples from 51 patients with t(8;21) AML diagnosed in five centers and tested all samples by two differ ent RT-PCR techniques (a nested technique and a one-step technique, with a sensitivity of 10(-6) and 10(-5), respectively) in two different laboratori es. Results: Samples from 14 patients in long persistent CR (median follow-up d uration, 112 months) were taken at least twice, and all were PCR-negative b y both techniques, Samples were prospectively taken from 37 patients after achievement of first CR and/or second CR, before intensive consolidation tr eatment, and every 3 to 6 months after completion of therapy. Patients who converted to PCR negativity with the one-step technique (60%) or both techn iques (48%) after CR achievement had a longer CR duration than those with p ersistently positive PCR results (two-sided log-rank test, P = .0001), Pati ents who became PCR-negative with the one-step technique before intensive c onsolidation (23%) had a lower relapse rate (11% v 72%) and a longer CR dur ation than those who remained persistently PCR-positive at that point (two- sided log-rank test, P = .0015). Conclusion: Patients with AML with t(8;21) in longterm remission were all P CR-negative. In prospectively studied patients, a good correlation was foun d between negative PCR results and absence of relapse. Early negative resul ts with the one-step RT-PCR technique, before consolidation treatment, seem ed to carry an especially good prognosis, suggesting that RT-PCR analysis c ould help in choosing the type of consolidation therapy in patients with t( 8;21) AML, (C) 2000 by American Society of Clinical Oncology.