Adolescent and Young Adult Oncology Patients with Acute Lymphoblastic Leukemia: Shifting Location of Care over Time
Authors: Alvarez Elysia , Muffly Lori S. , Li Qian , Brunson Ann M , Wun Ted , Chamberlain Lisa , Keegan Theresa 
Published: October 2019

Abstract
Background
Over the past decade, research has demonstrated superior outcomes for adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) when they are treated on pediatric versus adult ALL protocols, which occurs more frequently at academic centers. We hypothesized that this knowledge resulted in a greater proportion of younger adults with ALL receiving treatment at National Cancer Institute (NCI)/Children's Oncology Group (COG) designated centers over the past decade, and that an increased proportion of younger AYAs (ages 18-21) received care at pediatric (COG) versus adult centers.
Methods
We used the Office of Statewide Health Planning and Development patient discharge database to conduct a retrospective analysis of AYA patients with ALL, ages 18 to 25 and diagnosed and treated in California from 2004 to 2013. The primary outcome was receiving care at a NCI/COG designated center up to 5 years after diagnosis. Multivariable logistic regression was used to determine socio-demographic factors associated with AYAs ever receiving care from an NCI/COG designated center. Descriptive analyses were used to evaluate changes in the percentage of admissions from NCI and COG designated centers over time using a chi-square test to make comparison of proportions over time.
Results
There were 703 patients, ages 18-25 years (52.5%, 18-21; 47.5%, 22-25 years) who were newly diagnosed with ALL and hospitalized in California between 2004 and 2013. Sixty-five percent were male and 51% had private insurance. Of these patients, 37% always received care at an NCI/COG center, while 28% sometimes and 35% never received care at these centers. Younger AYAs (18-21 years) had a higher odds of ever being discharged from a NCI/COG center (OR 1.52, CI 1.10-2.10), while AYAs living farther from a NCI/COG center were less likely to receive care at these centers (OR 0.45, CI 0.27-0.76 for 10-20 vs 0-5 miles). Over the past decade, there was an increase in the percentage of admissions to NCI/COG centers among 18-21 year-olds (53% in 2004 to 72% in 2013; p<0.001), whereas there was no significant increase for 22-25 year-olds (44% in 2004 to 49% in 2013; p=0.435) (Figure). When admissions to an NCI and COG center were considered separately, differences were observed by age group. There was a lower percentage of admissions to NCI centers over time in 18-21 year-olds (34% in 2004 to 27% in 2013; p=0.183), but a significant increase in admissions to NCI centers in 22-25 year-olds (27% in 2004 to 40% in 2013; p=0.035). Alternatively, there was a significant increase in the percentage of admissions to COG centers in the 18-21 year-olds (48% to 67%; p<0.001), with a somewhat smaller increase in admissions to COG centers in 22-25 year-olds (25% to 32%; p=0.278) from 2004 to 2013.
Conclusions
Over the past decade, approximately 37% of younger (18-25 years) AYAs with ALL always received care at NCI/COG designated centers, with younger age and shorter geographical distance to a NCI/COG designated center being the main predictors for receiving care at these centers. Over the study period, the percentage of admissions increased at NCI centers for 22-25 year-olds and COG centers for 18-21 year-olds. These findings support our hypothesis that there has been a shift in treatment of younger AYAs (18-21 years) to COG designated centers over the past decade. Further research is warranted to determine the roles that referral patterns, insurance networks, patient preference and other barriers play in receiving care at NCI and/or COG institutions and the effect of care at these centers on survival in population-based data.
Figure Percent of Admissions (Ages 18 to 21 vs 22 to 25) at NCI/COG Designated Centers with a Diagnosis of Acute Lymphoblastic Leukemia, 2004 to 2013 Figure. Percent of Admissions (Ages 18 to 21 vs 22 to 25) at NCI/COG Designated Centers with a Diagnosis of Acute Lymphoblastic Leukemia, 2004 to 2013

Disclosures
Wun: Janssen Scientific Affairs, LLC: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi: Research Funding.