The prognostic benefit from intermediate-dose cytarabine as consolidation therapy varies by cytogenetic subtype in t(8;21) acute myeloid leukemia: a retrospective cohort study

BACKGROUND: Patients with different karyotypes had different prognosis in t(8;21) acute myeloid leukemia (AML). Cytarabine (Ara-C) plays an important role as consolidation therapy in t(8;21) AML. T(8;21) AML patients with different karyotypes responded differently to post-remission therapy with Ara-C. However, the optimum dose of Ara-C in patients with different karyotypes remains unclear. METHODS: From January 2002 to September 2018, a total of 188 younger adult (14–60 years) patients with t(8;21) AML were enrolled in this retrospective study. Cytogenetic analysis and aberration descriptions followed the International System for Human Cytogenetic Nomenclature. All the patients achieved first complete remission (CR1) after induction chemotherapy. Patients received low-dose Ara-C [LDAC (<1 g/m(2))], intermediate-dose Ara-C [IDAC (1–1.5 g/m(2))], or high-dose Ara-c [HiDAC (2–3 g/m(2))] regimens as consolidation therapy after CR1. All patients were followed for survival or relapse until death, or study completion. We analyzed the prognosis of LDAC, IDAC, and HiDAC regimens as consolidation therapy in patients with different karyotypes. The primary endpoint was overall survival (OS) and the secondary endpoint was relapse-free survival (RFS). RESULTS: The results showed IDAC significantly improved OS compared with LDAC [hazard rate (HR) =0.55, P=0.0375] when the clinical factors were adjusted. However, no significant difference between HiDAC and IDAC was found. Subgroup analysis further showed that the OS advantage of IDAC was focused on patients with additional cytogenetic abnormalities, including loss of X chromosome (-X), del(9q), or complex karyotype (group B, HR =0.21, P=0.0125), but not on patients with t(8;21)-only or additional loss of Y chromosome (-Y) cytogenetics (group A, HR =0.77, P=0.4804) in multivariate analysis. Similarly, better OS was shown after IDAC than LDAC consolidation in patients in group B, whether they received allogeneic hematopoietic stem cell transplantation (allo-HSCT) or not, but not in group A. CONCLUSIONS: IDAC was suitable for patients with additional -X, del(9q), or complex karyotype, while LDAC might be sufficient for patients with t(8;21)-only or additional -Y cytogenetics. It suggested that t(8;21) AML patients with different karyotypes should use different consolidation regimens.