Observational Study
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Hematol. Aug 6, 2014; 3(3): 105-114
Published online Aug 6, 2014. doi: 10.5315/wjh.v3.i3.105
Age is an independent adverse prognostic factor for overall survival in acute myeloid leukemia in Japan
Hiroaki Ohnishi, Osamu Imataki, Yasunori Kawachi, Makoto Ide, Kimihiro Kawakami, Masato Waki, Hidetaka Takimoto, Yasuo Hoshijima, Tetsuya Fukumoto, Kensuke Matsumoto, Fusako Waki, Akihito Matsuoka, Takamichi Shintani, Makiko Uemura, Shigeyuki Yokokura, Teruhisa Taoka, Takuya Matsunaga
Hiroaki Ohnishi, Osamu Imataki, Tetsuya Fukumoto, Kensuke Matsumoto, Fusako Waki, Akihito Matsuoka, Takamichi Shintani, Makiko Uemura, Shigeyuki Yokokura, Takuya Matsunaga, Department of Internal Medicine, Division of Endocrinology and Metabolism, Hematology, Rheumatology and Respiratory Medicine, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
Hiroaki Ohnishi, Yasunori Kawachi, Makoto Ide, Department of Internal Medicine, Division of Hematology, Takamatsu Red Cross Hospital, Kagawa 760-0017, Japan
Kimihiro Kawakami, Masato Waki, Department of Internal Medicine, Division of Hematology, Kagawa Prefectural Central Hospital, Kagawa 760-8557, Japan
Hidetaka Takimoto, Department of Internal Medicine, Division of Hematology, Kagawa Rosai Hospital, Kagawa 763-8502, Japan
Yasuo Hoshijima, Department of Internal Medicine, Division of Hematology, Takamatsu Municipal Hospital, Kagawa 760-8538, Japan
Teruhisa Taoka, Department of Internal Medicine, Division of Hematology, Sakaide City Hospital, Kagawa 762-0031, Japan
Author contributions: Ohnishi H and Imataki O contributed equally to this work; Ohnishi H, Imataki O and Matsunaga T conceived and designed the study, analyzed and interpreted the data, wrote the paper; Kawachi Y, Ide M, Kawakami K, Waki M, Takimoto H, Hoshijima Y, Fukumoto T, Matsumoto K, Waki F, Matsuoka A, Shintani T, Uemura M and Yokokura S acquired the data, revised the paper; all authors approved the final version of the report.
Correspondence to: Osamu Imataki, MD, Department of Internal Medicine, Division of Hematology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan. oima@med.kagawa-u.ac.jp
Telephone: +81-87-8912145 Fax: +81-87-8912147
Received: December 11, 2013
Revised: April 20, 2014
Accepted: May 28, 2014
Published online: August 6, 2014
Processing time: 313 Days and 6.9 Hours
Abstract

AIM: To elucidate risk factors for survival of elderly acute myeloid leukemia (AML) patients in a real-world practice by observational study.

METHODS: We conducted a population-based study in 213 adult and elderly AML patients (127 males and 86 females) in Kagawa Prefecture, Japan. To construct this cohort, we gathered all data for patients diagnosed with AML at 7 hospitals in Kagawa between 2006 and 2010. The primary end point was overall survival (OS) after AML diagnosis. Unadjusted Kaplan-Meier survival plots were used to determine OS in the overall cohort. Multivariate analysis was used to determine the independent adverse prognostic factors for OS, with the covariates of interest including age, gender, race/ethnicity, CCI, education, median income, metropolitan statistical area size and history of myelodysplastic syndrome.

RESULTS: The average population of Kagawa during the study period was 992489, and the incidence of AML was 4.26 per 100000 person-years. A total of 197 patients with non-acute promyelocytic leukemia (non-APL) (119 males and 78 females) were also included. The median age of non-APL patients was 70 years (average 67, range 24-95). The 5-year OS rate was 21.1%. Subsequent analysis by age group showed that the survival rate declined with age; the 5-year OS rates of non-APL patients younger than 64 years, 65-74 years, and older than 75 years were 41.5%, 14.1%, and 8.9%, respectively. Multivariate analysis revealed that unfavorable risk karyotype, older age, poor performance status (PS) (3-4), lack of induction chemotherapy, and antecedent haematological disease were independent prognostic predictors. In the subgroup analysis, we also found that older patients with non-APL had lower complete remission rates and higher early death rates than younger patients, irrespective of PS. However, intensive chemotherapy was a significant predictor for longer survival not only in the patients < 75 years of age, but also in those over 75 with PS 0-2.

CONCLUSION: Age would contribute considerable life expectancy to indicate induction chemotherapy with eligible dose of cytotoxic drugs for a favorable case even in advanced elderly.

Keywords: Acute myeloid leukemia; Elderly; Adverse prognostic factor; Overall survival; Population-based study

Core tip: The prevalence of acute myeloid leukemia (AML) is increasing among elderly patients in Japan. Our population-based observational study revealed that age was an independent prognostic factor in a real-world practice for the treatment of AML patients. Although we found that AML patients older than 75 years had lower complete remission rates and higher early death rates than patients younger than 75 years, an appropriately intensified induction chemotherapy would be helpful to prolong the survival of elderly AML patients with better performance status (PS) (1-2). The intensity of chemotherapy should thus be adjusted according to age and PS.