Long-term outcomes of de novo acute myeloid leukemia in Thai patients

Acute myeloid leukemia (AML) is the heterogeneous disease. As per previous reports, there are some differences in clinical features and cytogenetic biomarkers of AML among different ethnic backgrounds. Therefore, we conducted a retrospective study to analyze clinical outcomes and predictive factors of Thai AML patients receiving chemotherapy treatment.

The authors performed a retrospective analysis of 106 adults with newly diagnosed de novo AML at Ramathibodi Hospital between 2003 and 2007. Of 101 patients with non- M3 subtype, the patients received induction and consolidation chemotherapy with anthracyclin plus cytarabine based regimens (3 + 7). All patients achieving complete remission (CR) were treated with intensive chemotherapy using intermediate dose cytarabine plus anthracyclin based protocol. All patients with M3 subtype, the induction chemotherapy consisted of a combination of all-trans retinoic acid (ATRA) and anthracyclin. All patients achieving complete remission (CR) were treated with three courses of mitoxantrone as consolidation chemotherapy, followed by maintenance chemotherapy with methotrexate, etoposide and ATRA.

Of the 106 patients, median age was 43.5 years (15-73 years) and 19 (17.9%) were older than 60 years. Fifty-six patients (52.8%) were female. Common subtypes were M4 (28.3%), M1 (26.4%) and M2 (20.8%). Of the 95 patients who were performed with cytogenetic analysis, 55 (58%) had abnormal karyotype. AML with recurrent cytogenetic translocations, complex chromosome, trisomy 8, polyploidy, del 5q and del 7q were found in 16.8, 6.3, 5.3, 5.3, 2.1 and 3.2%, respectively. Most patients (70.5%) had intermediate-risk cytogenesis. Eighty patients (75.5%) were treated with idarubicin and cytarabine induction regimen. Of the 96 evaluable patients, 60 (62.5%) achieved complete remission (CR), 38 (39.6%) with the first course of chemotherapy. Median time to CR was 54 days (25-168 days). The CR rate was 78.6% for the good-risk cytogenetic group, 67.2% for the intermediate- risk cytogenetic group, and 37.5% for the poor-risk cytogenetic group. Median follow-up time was 10.4 months, 5-year-DFS and 5-year-OS were 41 and 22.2%, respectively. Patients with poor-risk cytogenetic factors had significantly lower CR rate (p = 0.021). The CR status significantly predicted OS (p < 0.001).

The overall complete remission rate of Thai AML patients is in 60%. Only a small proportion of the presented patients have long-term DFS and OS, the significant factor for predicting survival of Thai AML patients is the complete remission status. Poor-risk cytogenetic factors are associated with poor treatment outcomes.