Although most children and adolescents with cancer have mild illness from COVID-19 infection, some do experience severe disease and a small percentage even die, according to a recent analysis.
The findings, published online in Lancet Oncology, represent the first global registry data spanning different income groups to report COVID-19 outcomes in pediatric oncology patients.
“We wanted to create a global pool of evidence to answer the question: Do we see severe [COVID-19] infection [in children with cancer]?” corresponding author Sheena Mukkada, MD, St. Jude Children’s Research Hospital, Memphis, said in an interview.
In a cohort of 1,319 pediatric patients followed for 30 days, Dr. Mukkada and colleagues reported that 80% of these patients had asymptomatic to moderate disease from COVID-19, while 1 in 5 experienced severe or critical illness and almost 4% died – four times the mortality rate observed in published cohorts of general pediatric patients.
The results highlight that “children and adolescents with cancer generally recover without incident from COVID-19, but can have a severe course of infection,” the authors concluded.
And knowing that some children can get very sick, investigators wanted “to identify who these patients are so that we can prioritize and protect that group,” she added.
Echoing that sentiment, Kathy Pritchard-Jones, MD, president of the International Society of Paediatric Oncology and coauthor on the study, noted in a press release that, “by working together to create this global registry, we have enabled hospitals around the world to rapidly share and learn how COVID-19 is affecting children with cancer.”
Dr. Pritchard-Jones commented that overall these results provide reassurance that “many children can continue their cancer treatment safely, but they also highlight important clinical features that may predict a more severe clinical course and the need for greater vigilance for some patients.”
Inside the Global Registry data
The Global Registry of COVID-19 in Childhood Cancer, created jointly by St. Jude Children’s Research Hospital and SIOP, included data from 131 institutions in 45 countries. Children recruited into the registry between April 2020 and February 2021 ranged in age from infancy to 18 years old.
Most patients remained asymptomatic (35%) or experienced mild to moderate illness (45%), though 20% did develop severe or critical illness.
The investigators highlighted several factors associated with a greater risk of developing more severe illness from COVID-19, which included cancer type, intensity of therapy, age, absolute lymphocyte count, and presence of comorbidities or COVID-19 symptoms.
Notably, more than 80% of either severe or critical infections occurred in patients with hematologic malignancies – with 56% of cases in patients with acute lymphoblastic lymphoma or acute lymphoblastic leukemia – followed by extracranial solid tumors (15.8%), and central nervous system tumors (2.7%).
In patients with acute lymphoblastic leukemia or acute lymphoblastic lymphoma, severe or critical disease was most common in those receiving induction therapy (30%), relapse or refractory therapy (30%), and those in the maintenance or continuation phase of therapy (19%).
Older age was associated with a higher likelihood of having severe disease – with the lowest risk in infants (9.7%) and the highest in the 15- to 18-year-old cohort (27.3%).
Patients with lymphopenia who had an absolute lymphocyte count of 300 cells per mm3 or less and an absolute neutrophil count of 500 cells per mm3 or more also had an elevated risk of severe illness from COVID-19.
Regarding whether the presence of lymphopenia or neutropenia should change the treatment approach, Dr. Mukkada noted that, when possible, these patients should receive antiviral treatment, such as remdesivir, if the center has antivirals, or be prioritized for hospital admission.
Modifying cancer treatment might be recommended if patients are highly lymphopenic or have very low neutrophil counts, but a more effective strategy is simply to ensure that age-eligible children and adolescents with cancer or who have had a hematopoietic stem-cell transplantation have been fully vaccinated against COVID-19. For children who are not yet age-eligible, everyone around them should be vaccinated.
Pediatric patients in low- and middle-income countries were also more likely to have severe or critical outcomes from COVID-19 (41.7%), compared with patients in other income groups (23.9%).
The impact of COVID-19 “has been felt in every corner of the world, but particularly in low- and middle-income countries, compared to high-income countries,” senior author Carlos Rodriguez-Galindo, MD, global director at St. Jude, said in a statement.
In terms of the intersection of cancer treatment and COVID diagnosis, almost 83% of pediatric patients were receiving treatment for their cancer. Chemotherapy was withheld in about 45% of these patients and some modification to the treatment regimen occurred in almost 56% of participants on active therapy.
“Treatment modifications were least common in patients from upper-middle–income countries, compared with other income groups,” the authors wrote.
Although an interesting observation, Dr. Mukkada noted that the registry data could not explain why treatment modifications occurred less frequently in upper-middle income countries as opposed to high-income and lower-income countries.