Pediatric vs young adult ALL patients: What’s different about them?
Key Takeaways
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"Typically, childhood regimens are more intense than adult regimens. [Some] of this has to do with younger people having fewer comorbidities than adults do. For instance, it would be much less common for younger people to have diseases like diabetes and high blood pressure, which frequently cause us to adjust therapies in adults." — Daniel Landau, MD, Medical Director of virtual hematology at the Medical University of South Carolina
Find more of your peers' perspectives and insights below.
Thanks to major treatment advances, survival rates for children with acute lymphoblastic leukemia (ALL) now top 90%—a huge win. But for others, the outlook isn’t as bright: Survival rates for adolescents and young adults (AYAs, ages 15 to 39), for example, drop to around 54%–74%. Treatment side effects in older patients also tend to hit harder.[]
So what’s driving the gap? Let’s dig into recent research and expert insights to explore how ALL shows up—and plays out—differently in pediatric patients
Pediatric patients have the edge—but why?
The notable survival gap between younger and older children with ALL persists despite advances in diagnostics and targeted therapies.
Daniel Landau, MD, Medical Director of virtual hematology at the Medical University of South Carolina, explains, "Leukemia treatment is an active area of controversy. Typically, childhood regimens are more intense than adult regimens. [Some] of this has to do with younger people having fewer comorbidities than adults do. For instance, it would be much less common for younger people to have diseases like diabetes and high blood pressure, which frequently cause us to adjust therapies in adults. But, in addition to this, the diseases are often a little different, and the common patterns of mutations are often different."
Seth Karol, MD, a pediatric oncologist at St. Jude Children's Research Hospital, says, “Adults also have more side effects from ALL therapy than do children.”
Older patients tend to experience more severe side effects from treatment—grade 3 or 4 toxicities like hepatotoxicity, thrombosis, and hyperglycemia. These complications often force doctors to lower the dose or stop treatment early, especially when it comes to critical agents like asparaginase.[]
Differences in disease biology
Dr. Karol says that “ALL in adults is often harder to treat than in children. This is because the genetic changes in ALL seen in adults are frequently harder to treat than the changes seen in children.” AYA patients with ALL commonly present with high-risk genetic profiles,[] including IKZF1 deletions, BCR-ABL1 (Philadelphia chromosome, Ph+), Ph-like ALL with CRLF2 rearrangements, and hypodiploidy.
Pediatric cases, however, frequently show favorable subtypes such as ETV6-RUNX1 fusion and hyperdiploidy, all of which translates to better outcomes.[] These genetic differences directly impact treatment resistance and relapse potential.
Pediatric protocols, better outcomes
Treatment regimens vary significantly in ALL, but studies have suggested that AYAs receiving pediatric-inspired protocols—pediatric regimens administered at pediatric centers by pediatric teams—generally achieve better outcomes. Specifically, they have shown improved survival over AYAs treated in adult oncology units.
The CALGB 10403 trial, however, evaluated use of an intensive pediatric treatment regimen administered by adult treatment teams.[] Patients in this trial were 16–39 years of age. The results yielded an estimated 3-year overall survival rate of 73%, an improvement over the 55% reported for this age group in earlier studies. At the time of data reporting, median overall survival had not been reached. Hepatic and thrombotic complications during induction therapy, though, were more common than reported in younger patients in a previous trial.
Why age matters
It’s worth understanding why older patients with ALL often don’t fare as well—evidenced especially in psychosocial factors. Dr. Karol notes that adults face added complications that children typically don’t. “Their insurance is frequently tied to employment, and maintaining employment during intensive phases of therapy can be a challenge," he says.
There are also different emotional and social stressors at play. "Young adults also experience side effects differently from younger children, with worries such as physical appearance and fertility felt differently by young adults compared to children,” Dr. Karol says.
For teens and adults, mental health struggles like anxiety, depression, and social isolation can impact adherence and overall outcomes. Educational delays, job loss, and a disrupted sense of independence only compound the challenge. Understanding these differences helps reinforce just how critical age-specific care is—and why younger kids often have a smoother path through treatment.
Physiologic factors
It’s important to note that pediatric patients with ALL benefit from several physiologic advantages.
Children typically have more robust organ function, including better liver, kidney, heart, and lung health, compared to adults who may experience age-related decline. Their greater physiological reserve allows them to better withstand the stress of chemotherapy and radiation.
Additionally, children have a higher proportion of active bone marrow, which aids in blood cell production during treatment.
Children also metabolize chemotherapy drugs differently, which can affect both drug efficacy and side effects. These physiological factors contribute to why younger children often tolerate treatment better than older patients, emphasizing the importance of age-specific care.