Elsevier

Leukemia Research

Volume 36, Issue 2, February 2012, Pages 140-145
Leukemia Research

Racial differences in presentation, referral and treatment patterns and survival in adult patients with acute myeloid leukemia: A single-institution experience

https://doi.org/10.1016/j.leukres.2011.10.018Get rights and content

Abstract

Background

Disease presentation and outcomes differ by race in a number of malignancies, but data in adult acute myeloid leukemia (AML) are limited.

Materials and methods

We conducted a retrospective analysis of pretreatment characteristics, referral and treatment patterns, and outcomes in 548 AML patients evaluated at the University of Maryland Greenebaum Cancer Center, a tertiary care referral center in Baltimore, MD, from 2000 through 2009. Cases were analyzed for time from diagnosis to referral, age, race, gender, socioeconomic status, antecedent hematologic disorder, cytotoxic or radiation therapy for prior malignancy, karyotype, fms-like tyrosine kinase receptor-3 (FLT3) mutations, intensive chemotherapy, clinical trial participation, hematopoietic stem cell transplantation (HSCT) and overall survival (OS).

Results

Black patients (n = 105) were younger than white patients (n = 396) (54 vs. 61 years, p < 0.001), were more commonly female (55% vs. 45%, p < 0.001), and had a lower estimated median household income ($42,677 vs. $53,534 per year, p < 0.001). Black patients more frequently had complex karyotypes (26% vs. 12%, p = 0.002) and less frequently normal karyotypes (27% vs. 42%, p = 0.02). FLT3 mutation frequency was similar. Time to referral and proportion of patients receiving intensive chemotherapy did not differ, but both clinical trial participation (43% vs. 54%, p = 0.04) and HSCT (17% vs. 35% for patients ≤70 years old, p = 0.001) were less frequent in blacks than whites. Nevertheless, OS was similar in all black and white patients (median 15 vs. 14 months, p = 0.23), and when stratified by age, gender and karyotype risk classification.

Conclusion

AML presentation and treatment differed in black and white patients, but OS was similar. Black patients appear to have barriers to clinical trial participation and HSCT, and there may be barriers to tertiary care referral for black males.

Introduction

Acute myeloid leukemia (AML) is characterized by maturation arrest of a malignant clone of myeloid cells, with inhibition of normal hematopoiesis. AML is the common type of acute leukemia affecting adults, and its incidence increases with age. The age-adjusted incidence rate of AML in the United States is 3.5 per 100,000 people per year. AML is more common in males, with a male to female ratio of 1.48, and is also more common in whites, with a white to black ratio of 1.2 [1].

Racial differences in clinical characteristics and outcome have been identified in a number of cancers, with blacks often having shorter overall survival (OS) than whites. This relationship has been identified in head and neck [2], [3], [4], skin [5], esophageal [6], colon [7], prostate [8], [9], [10], ovarian [10] and breast cancers [10], [11]. The observed differences between populations are likely multifactorial, reflecting differences in access to care due to socioeconomic disparities, environmental exposures, cultural differences, tumor biology, and genetic mutations or polymorphisms influencing response to and/or toxicity of chemotherapeutic agents [12]. Socioeconomic disparities are generally thought to be the most important of these determinants and indeed many observed racial disparities are at least mitigated when these factors are taken into account.

Racial differences in disease presentation and treatment outcome have not been extensively studied in adult AML. Karyotype is the most significant predictor of outcome in AML, but only limited information is available on the distribution of AML karyotypes across races [13]. Additionally, molecular abnormalities with prognostic significance, most notably mutations of fms-like tyrosine kinase receptor-3 (FLT3), have been identified as having strong prognostic significance in AML [14], but there is little information available about their incidence in different races. Finally, data on outcomes by race are limited and inconsistent [10], [13], [15], [16].

To assess racial differences in pretreatment characteristics, referral and treatment patterns and outcome in adult AML, we studied patients evaluated and treated from 2000 through 2009 at the University of Maryland Greenebaum Cancer Center (UMGCC) in Baltimore, Maryland, a tertiary care referral center with a relatively high proportion of minority patients.

Section snippets

Study population

We conducted a retrospective study of all patients with a diagnosis of AML evaluated at UMGCC from January 1, 2000 through December 31, 2009. This study was approved by the University of Maryland School of Medicine Institutional Review Board.

Data collection

Data were obtained from retrospective electronic and paper chart review. Information collected included diagnosis date, date of referral to UMGCC, self-reported race, gender, date of birth, zip code of residence, presence or absence of an antecedent

Results

A total of 548 patients with a diagnosis of AML were identified, of whom 399 (73%) were white, 105 (19%) black, 22 (4%) Hispanic and 22 (4%) Asian. Karyotype data were available for 510 (94%) and FLT3 data for 177 (32%), with availability of karyotype and FLT3 data similar for all races. As the vast majority of our population was white or black, comparisons were limited to differences between these two groups.

Time from AML diagnosis to referral to UMGCC did not differ in blacks and whites (p = 

Discussion

In this study in a single institution with a 19% black AML population, we found that black adult AML patients were younger, were more commonly female and had a higher incidence of complex karyotypes as well as a lower incidence of normal karyotypes, but had similar survival when compared to whites. FLT3 mutations were equally frequent in black and white patients, but were a stronger predictor of OS in blacks than in whites with intermediate-risk karyotypes. To our knowledge, our study

Conflict of interest

There are no conflicts of interest to disclose.

Acknowledgements

Contributions: JB was the principal investigator and takes primary responsibility for the paper. YN was responsible for collection of cytogenic data. JB, AD, IG, MT, MB wrote the paper. JB performed data collection and analysis. IG, MT, MB assisted with data collection and AD assisted with statistical analysis. All authors had final approval of the manuscript.

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