Hematopoietic stem cell transplantation among patients with leukemia of all ages in Texas

Trends in volumes and survival after hematopoietic cell transplantation in racial/ethnic minorities

ABSTRACT

There has been an increase in volume as well as an improvement in overall survival (OS) after hematopoietic cell transplantation (HCT) for hematologic disorders. It is unknown if these changes have affected racial/ethnic minorities equally. In this observational study from the Center for International Blood and Marrow Transplant Research of 79 904 autologous (auto) and 65 662 allogeneic (allo) HCTs, we examined the volume and rates of change of autoHCT and alloHCT over time and trends in OS in 4 racial/ethnic groups: non-Hispanic Whites (NHWs), non-Hispanic African Americans (NHAAs), and Hispanics across 5 2-year cohorts from 2009 to 2018. Rates of change were compared using Poisson model. Adjusted and unadjusted Cox proportional hazards models examined trends in mortality in the 4 racial/ethnic groups over 5 study time periods. The rates of increase in volume were significantly higher for Hispanics and NHAAs vs NHW for both autoHCT and alloHCT. Adjusted overall mortality after autoHCT was comparable across all racial/ethnic groups. NHAA adults (hazard ratio [HR] 1.13; 95% confidence interval [CI] 1.04-1.22; P = .004) and pediatric patients (HR 1.62; 95% CI 1.3-2.03; P < .001) had a higher risk of mortality after alloHCT than NHWs. Improvement in OS over time was seen in all 4 groups after both autoHCT and alloHCT. Our study shows the rate of change for the use of autoHCT and alloHCT is higher in NHAAs and Hispanics than in NHWs. Survival after autoHCT and alloHCT improved over time; however, NHAAs have worse OS after alloHCT, which has persisted. Continued efforts are needed to mitigate disparities for patients requiring alloHCT.

Reducing barriers of access and care related to hematopoietic cell transplantation and cellular therapy: The mission-driven role of the national marrow donor program

The treatment of malignant and nonmalignant hematologic disorders continues to benefit from significant scientific advancement and progress in the use of hematopoietic cell transplantation and cellular therapies. However, barriers associated with receiving these lifesaving treatments and care remain, which necessitate innovative approaches to overcome, so all persons in need can receive these therapies. This article reviews barriers to receiving hematopoietic cell transplantation and cellular therapies, and highlights novel approaches taken by the National Marrow Donor Program in reducing barriers for all patients in need.

Racial disparities in hematopoietic stem cell transplant: a systematic review of the literature

BACKGROUND

Hematopoietic stem cell transplant (HSCT) is an expensive and complex treatment regimen that can be curative in many diseases of the bone marrow, including malignant and non-malignant conditions. The introduction of the Affordable Care Act increased access to potential candidates and removed or reduced many barriers previously identified in the literature, however, racial disparities continue to persist. As HSCT expands its utilization and indications, there is a continued need to understand the multifactorial barriers which lead to inequalities in transplant referral, utilization, and survival. The objective of this systematic review is to summarize these racial disparities, expand the current understanding of the literature, and determine whether the increases in insurance status from Medicaid expansion have played a role in HSCT utilization and survival rates by race.

METHODS

We explored studies based on retrospective reviews, literature reviews, and focus groups with the key-terms of 'race', 'hematopoietic stem cell transplant', and 'disparities'. The included studies were extracted from Cochrane and Medline databases. After screening for relevancy to research aims and objectives, 10 articles were utilized for background information and discussion, while 30 articles were categorized into main groups of outcomes, chiefly, (I) access/referral to transplant and (II) survival.

RESULTS

Eight of the eleven retrospective reviews found substantial variation in access to HSCT by ethnic minorities (Black, Hispanic, or Asian) when compared to their Caucasian counterparts. Thirteen of the fourteen publications found racial disparities in either overall survival, progression free survival, treatment related mortality, relapse, or combinations of these outcomes. The majority of the studies evaluated African American patients with six of eight studies showing significantly elevated mortality compared to Caucasian patients.

DISCUSSION

Substantial variation exists in access to HSCT, particularly in black patients. Having less generous insurance coverage was previously hypothesized to reduce the likelihood of HSCT utilization. Studies performed after full implementation of the Affordable Care Act continue to show poorer survival among ethnic minorities, particularly black patients, despite this increased coverage. Perceived racial bias and health-related stigma, as well as physician decisions and delay in referral process are likely contributing factors.

Race as a factor in donor selection and survival of children with hematologic malignancies undergoing hematopoietic stem cell transplant in Florida

BACKGROUND

Previous studies have explored posthematopoietic cell transplant (HCT) outcomes by race in adults; however, pediatric data addressing this topic are scarce.

PROCEDURE

This retrospective registry study included 238 White (W) and 57 Black (B) children with hematologic malignancies (HM) receiving first allogeneic HCT between 2010 and 2019 at one of the five Florida pediatric HCT centers.

RESULTS

We found no differences between W and B children in transplant characteristics, other than donor type. There was a significant difference in use of human leukocyte antigen (HLA)-mismatched donors (HLA-MMD) (53% W, 71% B, p = .01). When comparing HLA-MMD use to fully HLA-matched donors, B had relative risk (RR) of 1.47 (95% CI 0.7-3) of receiving a mismatched unrelated donor (MMUD), RR of 2.34 (95% CI 1.2-4.4) of receiving a mismatched related donor (MMRD), and RR of 1.9 (95% CI 0.99-3.6) of receiving a mismatched cord blood donor (MMCBD) HCT, respectively. There was no significant difference in the incidence of aGVHD (48% W, 35% B), p = .1, or cGVHD (19% W, 28% B, p = .1), or primary cause of death. Overall 24-month survival was 61% (95% CI 55%-68%) for W, and 60% (95% CI 48-75) for B children, log-rank p = .7. While HLA matching improved survival in W children, the number of B children receiving HLA-matched HCT was too small to identify the impact of HLA matching on survival.

CONCLUSIONS

In this contemporary cohort of children with HM, we found that B children were more likely to receive HLA-MMD transplants, but this did not adversely affect survival or GVHD rates.

Barriers to Hematopoietic Cell Transplantation for Adults in the United States: A Systematic Review with a Focus on Age

Hematopoietic cell transplantation (HCT) is an effective treatment for many hematologic malignancies, and its utilization continues to rise. However, due to the difficult logistics and high cost of HCT, there are significant barriers to accessing the procedure; these barriers are likely greater for older patients. Although numerous factors may influence HCT access, no formal analysis has detailed the cumulative barriers that have been studied thus far. We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to better categorize the barriers to access and referral to HCT, with a focus on the subgroup of older patients. We searched for articles published in English from PubMed, Embase, Cumulative Index for Nursing and Allied Health, and Cochrane Central Register of Controlled Trials between the database inception and January 31, 2020. We selected articles that met the following inclusion criteria: (1) study design: qualitative, cross-sectional, observational cohort, or mixed-method study designs; (2) outcomes: barriers related to patient and physician access to HCT; and (3) population: adults aged ≥18 years with hematologic malignancies within the United States. Abstracts without full text were excluded. QUALSYST methodology was used to determine article quality. Data on the barriers to access and referral for HCT were extracted, along with other study characteristics. We summarized the findings using descriptive statistics. We included 26 of 3859 studies screened for inclusion criteria. Twenty studies were retrospective cohorts and 4 were cross-sectional. There was 1 prospective cohort study and 1 mixed-method study. Only 1 study was rated as high quality, and 16 were rated as fair. Seventeen studies analyzed age as a potential barrier to HCT referral and access, with 16 finding older age to be a barrier. Other consistent barriers to HCT referral and access included nonwhite race (n = 16/20 studies), insurance status (n = 13/14 studies), comorbidities (n = 10/11 studies), and lower socioeconomic status (n = 7/8 studies). High-quality studies are lacking related to HCT barriers. Older age and nonwhite race were consistently linked to reduced access to HCT. To produce a more just health care system, strategies to overcome these barriers for vulnerable populations should be prioritized. Examples include patient and physician education, as well as geriatric assessment guided care models that can be readily incorporated into clinical practice.

Regional differences in access to hematopoietic stem cell transplantation among pediatric patients with acute myeloid leukemia

INTRODUCTION

Indications for hematopoietic stem cell transplantation (HSCT) in pediatric acute myeloid leukemia (AML) are primarily dependent on risk stratification at diagnosis and relapse status. We sought to determine whether access to HSCT is influenced by regional and socioeconomic factors.

METHODS

Children with newly diagnosed AML aged < 15 years between 2001 and 2015 were identified using the Cancer in Young People in Canada national population-based registry. Factors potentially associated with the receipt of HSCT were studied using univariate and multivariable logistic regression models.

RESULTS

Overall, 568 children with newly diagnosed AML were included and 262 (46%) received HSCT. A greater proportion of patients, 103/157 (65.6%), underwent HSCT after first or subsequent relapse compared to 159/411 (38.7%) patients who underwent transplant before relapse. Among patients for whom HSCT would be considered before relapse, factors associated with higher odds of HSCT in a multivariable analysis were: poor versus good-risk cytogenetics (Odds ratio [OR]: 30.0, 95% confidence interval [CI]: 7.7-117.0), diagnosis during 2012-2015 versus 2001-2006 (OR: 3.2, 95% CI: 1.6-6.3), diagnosis in eastern Canada versus central Canada (OR: 3.7, 95% CI: 1.9-7.3), and age 10-14 years versus age < 1 year (OR: 5.4, 95% CI: 2.3-12.8). Among patients for whom HSCT would be considered after first relapse, higher odds of HSCT was associated with diagnosis at a HSCT center (OR: 2.1, 95% CI: 1.1-4.1).

CONCLUSION

Patients diagnosed at a HSCT performing center and patients from eastern Canada had higher odds of receiving HSCT. This may suggest preferential access to HSCT for certain patients.

Sociodemographic disparities in chemotherapy and hematopoietic cell transplantation utilization among adult acute lymphoblastic and acute myeloid leukemia patients

Introduction

Identifying sociodemographic disparities in chemotherapy and hematopoietic cell transplantation (HCT) utilization for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) may improve survival for underserved populations. In this study, we incorporate neighborhood socioeconomic status (nSES), marital status, and distance from transplant center with previously studied factors to provide a comprehensive analysis of sociodemographic factors influencing treatments for ALL and AML.

Methods

Using the California Cancer Registry, we performed a retrospective, population-based study of patients ≥15 years old with ALL (n = 3,221) or AML (n = 10,029) from 2003 through 2012. The effect of age, sex, race/ethnicity, marital status, nSES, and distance from nearest transplant center on receiving no treatment, chemotherapy alone, or chemotherapy then HCT was analyzed.

Results

No treatment, chemotherapy alone, or chemotherapy then HCT were received by 11%, 75%, and 14% of ALL patients and 36%, 53%, and 11% of AML patients, respectively. For ALL patients ≥60 years old, HCT utilization increased from 5% in 2005 to 9% in 2012 (p = 0.03). For AML patients ≥60 years old, chemotherapy utilization increased from 39% to 58% (p<0.001) and HCT utilization from 5% to 9% from 2005 to 2012 (p<0.001). Covariate-adjusted analysis revealed decreasing relative risk (RR) of chemotherapy with increasing age for both ALL and AML (trend p <0.001). Relative to non-Hispanic whites, lower HCT utilization occurred in Hispanic [ALL, RR = 0.80 (95% CI = 0.65–0.98); AML, RR = 0.86 (95% CI = 0.75–0.99)] and non-Hispanic black patients [ALL, RR = 0.40 (95% CI = 0.18–0.89); AML, RR = 0.60 (95% CI = 0.44–0.83)]. Compared to married patients, never married patients had a lower RR of receiving chemotherapy [ALL, RR = 0.96 (95% CI = 0.92–0.99); AML, RR = 0.94 (95% CI = 0.90–0.98)] or HCT [ALL, RR = 0.58 (95% CI = 0.47–0.71); AML, RR = 0.80 (95% CI = 0.70–0.90)]. Lower nSES quintiles predicted lower chemotherapy and HCT utilization for both ALL and AML (trend p <0.001).

Conclusions

Older age, lower nSES, and being unmarried predicted lower utilization of chemotherapy and HCT among ALL and AML patients whereas having Hispanic or black race/ethnicity predicted lower rates of HCT. Addressing these disparities may increase utilization of curative therapies in underserved acute leukemia populations.

Factors affecting receipt of expensive cancer treatments and mortality: evidence from stem cell transplantation for leukemia and lymphoma

OBJECTIVE

To identify factors that affect whether patients diagnosed with either leukemia or lymphoma receive a stem cell transplant and secondly if receipt of stem cell transplantation is linked to improved survival.

DATA

California inpatient discharge records (2002-2003) for patients with either leukemia or lymphoma linked with vital statistics death records (2002-2005).

STUDY DESIGN

Bivariate Probit treatment effects model that accounts for both the type of treatment received and survival while controlling for nonrandom selection due to unobservable factors.

PRINCIPAL FINDINGS

Having private insurance coverage and residence in a well-educated county increased the chances a patient with either disease received HSCT. Increasing age and travel distance to the nearest transplant hospital had the opposite effect. Receipt of HSCT had a significant impact on mortality. We found the probability of death was 4.3 percentage points higher for leukemia patients who did NOT have HSCT. Receipt of HSCT reduced the chances of dying by almost 50 percent. The likelihood of death among lymphoma patients who underwent HSCT was almost 5 percentage points lower, a 70 percent reduction in the probability of death.

CONCLUSIONS

The findings raise concern about access to expensive, but highly effective cancer treatments for patients with certain hematologic malignancies.

Tertiary center referral patterns for patients with myelodysplastic syndrome are indicative of age and race disparities: a single-institution experience

Little is known about disparities in myelodysplastic syndromes (MDS). We performed a retrospective chart review of patients with MDS (n = 252) evaluated at the University of Maryland Greenebaum Cancer Center between 2000 and 2010. The median age at diagnosis was 65 years, which was lower than the median age of 76 years for patients with MDS in the Surveillance, Epidemiology and End Results database. Black males were younger than white males (62 vs. 68 years; p = 0.03) and had longer time to referral (9 vs. 1.5 months; p = 0.03), but black and white females did not differ in age or in time to referral. A difference in World Health Organization subtype classification was noted in black and white patients at diagnosis, but not at referral. There was no difference between all other pretreatment characteristics, treatment and survival by race. Our data suggest barriers to tertiary care referral for older patients and for black males.

Racial disparities in hematopoietic cell transplantation in the United States

Hematopoietic cell transplantation (HCT) is a highly specialized, expensive and resource-intense medical procedure that can be associated with racial disparities. We review the prevailing literature on racial disparities in HCT in the United States and describe areas for future research and interventions. We discuss the complexity of interpreting race as a biological and social determinant of disease in biomedical research, especially as it relates to HCT. In the United States, race is often a surrogate for socioeconomic, education and health insurance status. We also discuss some of the nuances to consider while reviewing the literature on racial disparities. Disparities by race exist in three areas related to HCT: donor availability, access to HCT and outcomes of HCT. African-Americans/Blacks have a lower likelihood of finding an unrelated donor. Race and ethnicity definitions are country-specific and reconciling race data can represent significant challenges to unrelated donor registries worldwide. African-Americans/Blacks do not have the same access to autologous and allogeneic HCT as Whites. Racial disparities in outcomes of HCT are more prevalent among allogeneic HCT than autologous HCT recipients. More research is required to understand the biological, social, cultural, medical and financial aspects of race that may influence access to HCT and survival after transplantation. Better understanding of racial disparities will minimize inequities, inform health policy, guide development of interventions targeted to eliminate disparities and ensure equitable access to HCT for all populations.

Practice variation in physician referral for allogeneic hematopoietic cell transplantation

Hematological malignancy patients not referred by their primary hematologist/medical oncologist suffer disparate access to allogeneic hematopoietic cell transplantation (HCT). However, investigation into physician, system and patient factors relevant to this decision making is lacking. We surveyed a national randomized sample of practicing hematologists/medical oncologists identified through the AMA (American Medical Association) masterfile. A modified Dillman approach was utilized to encourage survey response. From 1200 surveyed, a total of 113 physicians responded. In all, 68% were male, 62% identified as White/non-Hispanic, 79% practiced in non-academic settings and 80% reported spending 75-100% of their professional effort in clinical care. Using clinical vignettes, we detected significantly increased odds for HCT non-referral according to age (age 60 vs 30, odds ratio (OR) 8.3, 95% confidence interval (CI): 5.9-11.7, P<0.0001), insurance coverage (no coverage vs coverage, OR 6.9, 95% CI: 5.2-9.1, P<0.0001) and race (African-American vs Caucasian, OR 2.4, 95% CI: 1.9-2.9, P<0.0001). Physician (perception of HCT risks), system (insurance coverage) and patient (age, social support and co-morbid illness) factors were strongly endorsed by respondents as important determinants of their HCT referral practices. These data speak to important factors relevant to HCT referral practices, and highlight several opportunities for education and intervention to reduce current disparities.

Who is fit for allogeneic transplantation?

The use of allogeneic hematopoietic cell transplantation (HCT) has expanded progressively, facilitated by the increasing availability of unrelated donors and cord blood, and the inclusion of older patients as transplantation candidates. Indications remain diagnosis-dependent. As novel nontransplantation modalities have been developed concurrently, many patients come to HCT only when no longer responding to such therapy. However, patients with refractory or advanced disease frequently relapse after HCT, even with high-dose conditioning, and more so with reduced-intensity regimens as used for patients of older age or with comorbid conditions. Thus, patients with high-risk malignancies who have substantial comorbidities or are of advanced age are at high risk of both relapse and nonrelapse mortality and should probably not be transplanted. Being in remission or at least having shown responsiveness to pre-HCT therapy is generally associated with increased transplantation success. In addition, to handle the stress associated with HCT, patients need a good social support system and a secure financial net. They must be well informed, not only about the transplantation process, but also about expected or potential post-HCT events, including graft-versus-host disease and delayed effects that may become manifest only years after HCT.

Access to hematopoietic cell transplantation in the United States

Hematopoietic cell transplantation (HCT) is a highly specialized and resource-intense medical procedure that can be associated with disparities in access to transplantation. Barriers to access to HCT are multifactorial, complex, and interrelated. Our current knowledge of specific barriers that prevent access to HCT is very limited. As the utilization of HCT increases, it is imperative that underserved populations receive the benefit of this life-saving procedure. We review the prevailing literature on access to HCT and describe research priorities for eliminating disparities in transplantation. Better understanding of these complex barriers will minimize inequities, inform health policy, guide development of interventions targeted to eliminate disparities, and continue the expansion of HCT in the future.

Gender and ethnic differences in chronic myelogenous leukemia prognosis and treatment response: a single-institution retrospective study

BACKGROUND

In the last decade the importance of ethnicity, socio-economic and gender differences in relation to disease incidence, diagnosis, and prognosis has been realized. Differences in these areas have become a major health policy focus in the United States. Our study was undertaken to examine the demographic and clinical features of chronic myelogenous leukemia (CML) patients presenting initially at the LAC+USC Medical Center, which serves an ethnically diverse population.

RESULTS

Patients were evenly split by gender, overwhelmingly Hispanic (60.9%), and quite young (median age 39, range 17-65) compared with previously reported CML patient populations. Previous CML studies identified significant anemia (Hgb <12 g/dl), significant thrombocytosis (platelets >450 x 109/l), and significant leukocytosis (WBC >50 x 109/l) as significant adverse pretreatment prognostic factors. Using these indicators, in addition to the validated Hasford and Sokal scores, patients were stratified and analyzed via gender and ethnicity. A significantly greater proportion of women presented with significant anemia (p = 0.019, Fisher's exact test) and significant thrombocytosis (p = 0.041, Fisher's exact test) compared to men, although no differences were found in risk stratification or treatment response. MCV values for women were significantly (p = 0.02, 2-sample t-test) lower than those for men, suggesting iron deficiency anemia. Focusing on ethnicity, Hispanics as a whole had significantly lower Hasford risk stratification (p = 0.046, Fisher's exact test), and significantly greater likelihood (p = 0.016, Fisher's exact test) of achieving 3-month complete haematological remission (CHR) compared with non-Hispanics at LAC+USC Medical Center, though differences in treatment outcome were no longer significant with analysis limited to patients treated with first-line imatinib.

CONCLUSION

Female CML patients at LAC+USC Medical Center present with more significant adverse pre-treatment prognostic factors compared to men, but achieve comparable outcomes. Hispanic patients present with lower risk profile CML and achieve better treatment responses compared to non-Hispanic patients as a whole; these ethnic differences are no longer significant when statistical analysis is limited to patients given imatinib as first-line therapy. Our patients achieve response rates inferior to those of large-scale national studies. This constellation of findings has not been reported in previous studies, and is likely reflective of a unique patient population.