Intensive chemotherapy for elderly patients with acute myelogeneous leukemia: a propensity score analysis by the Japan Hematology and Oncology Clinical Study Group (J-HOCS)

The prognosis of acute myelogenous leukemia (AML) in the elderly patients is extremely poor. Although several previous studies have suggested that intensive chemotherapy is associated with a better prognosis, there may have been a selection bias. Therefore, we retrospectively evaluated the impact of intensive chemotherapy for AML in the elderly by stratifying patients according to a propensity score. Eighty-one AML patients aged 70 years or more were included in this study. Patients with acute promyelocytic leukemia were not included. A propensity score for the use of intensive chemotherapy was calculated from four factors at diagnosis. Forty-five patients received intensive chemotherapy, whereas 36 received low-dose or no chemotherapy. We stratified the patients into quartiles based on the propensity score. The numbers of patients in the first, second, third, and forth quartiles who received intensive chemotherapy were 5 of 21, 10 of 20, 12 of 20, and 18 of 20, respectively. A stratified log-rank test showed significantly better overall survival in the intensive chemotherapy group (P = 0.0088). Especially, in the combined second and third quartiles, which showed an equal tendency for intensive and non-intensive strategies; overall survival at 3 years was 37.5 % for the intensive chemotherapy group and 13.0 % for the non-intensive chemotherapy group (P = 0.0022). A conventional multivariate analysis confirmed that intensive chemotherapy was beneficial (hazard ratio 0.50, 95 % confidence interval 0.27-0.93, P = 0.028). In conclusion, intensive chemotherapy may prolong overall survival in elderly AML patients who are considered to be able to tolerate such treatment based on factors at diagnosis.