Most adolescents, young adults not treated with pediatric ALL protocols

Few adolescents and young adults with acute lymphoblastic leukemia treated by adult oncologists received treatment with pediatric-inspired regimens, according to the results of a population-based study.

“A multitude of retrospective analyses from U.S. and European cooperative groups have concluded that, independent of traditional ALL risk factors, adolescents and young adults [AYAs] with ALL have markedly superior outcomes when treated by pediatric oncologists following pediatric treatment protocols,” Lori Muffly, MD, MS, clinical assistant professor of medicine at Stanford University School of Medicine, and colleagues wrote. “In general, pediatric ALL regimens are more intensive and more highly regimented than adult regimens, most likely contributing to their improved success.”

No prior study has observed whether adult oncologists in the United States have adopted pediatric protocols when treating AYA patients.

Muffly and colleagues used the Greater Bay Area Cancer Registry to identify 304 patients aged 15 years to 39 years diagnosed with ALL between 2004 and 2014.

Standalone children’s facilities were designated as pediatric centers and facilities that do not treat children were designated as adult centers. Hospitals that treated children and adults and did not separately report pediatric and adult cases were only considered pediatric facilities if their patient’s treating physician specialized in pediatric oncology.

The study included data from 31 unique facilities, 10 of which were designated as pediatric centers. Adult centers comprised the remaining facilities, which included three NCI–designated cancer centers.

Seventy percent (n = 207) of AYAs received induction therapy at an adult facility. These patients tended to be older (P < .001), of non-Hispanic white race (P = .02) and were more likely to be treated at facilities with a low volume of AYAs with ALL (P < .0001).

The oldest subgroup of AYAs (aged 25-39 years) were exclusively treated at adult facilities, whereas 93% of the youngest subgroup (aged 15-18 years) received treatment at pediatric facilities.

The treatment of patients aged 19 years to 24 years significantly shifted from adult to pediatric centers over the course of the study period (P < .0001).

The researchers had access to induction regimen data from 75% (n = 229) of patients. All 89 patients treated at pediatric facilities between 2004 and 2014 received the pediatric regimen.

Eighty-one percent of AYAs received Children’s Oncology Group regimens, either on a clinical trial or as standard of care.

Twenty-seven percent (n = 56) of patients treated at adult facilities received regimens that could not be clearly defined as pediatric or adult. Treatment regimens became more identifiable over time: 81% of patients treated between 2013 and 2014 could be identified, compared with 57% from 2004 to 2007 and 79% from 2008 to 2012.

In total, 79% of AYAs received an adult AYA regimen. No AYA patient treated at an adult center prior to 2008 received a pediatric induction regimen, whereas 25% did so between 2008 and 2012. Between 2013 and 2014, 21% patients received a pediatric regimen.

Factors associated with receiving a pediatric regimen in an adult setting included treatment from 2008 to 2012, treatment at an NCI–designated cancer center, and treatment at a facility with two or more AYAs with ALL per year.

Study limitations included the lack of complete induction regimen data from all patients and the inclusion of patients from one geographic region.

“The data herein indicate that as recently as 2014, AYA patients with ALL were treated with a wide variety of treatment protocols, with the minority being pediatric-inspired ALL regimens,” Muffly and colleagues wrote. “Additional research is needed to determine factors that contribute to treatment selection for AYA patients with ALL by adult oncologists, and to understand barriers to increasing AYA care at higher-volume AYA ALL centers.” – by Cameron Kelsall

Disclosure: The researchers report no relevant financial disclosures.