New research has uncovered substantial differences in the rates of childhood cancers when considering a single year of age rather than grouping several years together. The study, published by Marcotte et al in the journal Cancer, also found that minority children seem to have different risks than White children for many types of cancer.
Cancer rates among children in the United States are typically reported in 5-year age groups, which may obscure important details, according to the authors. Also, racial and ethnic variations in pediatric cancer rates are typically presented in broad age categories.
Erin L. Marcotte, PhD, of the University of Minnesota, and her colleagues examined data from 2000 to 2017 from the Surveillance, Epidemiology, and End Results (SEER) Program, to assess cancer incidence rates by narrow age groups from birth to 39 years and across races and ethnicities.
“There are significant racial and ethnic disparities in the incidence of some childhood cancer types,” said Dr. Marcotte. “Additionally, unlike in cancers that occur in older adults, the incidence of cancer among children and young adults has striking variations by age at diagnosis, and studying these variations has often led to a deeper understanding of causes of childhood cancer.”
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Study Findings
Several cancer types showed substantial differences by single year of age, both overall and across racial and ethnic groups. For instance, Black children, adolescents, and young adults had lower rates of acute lymphoblastic leukemia (ALL) compared with White children, especially at ages 1 through 7 and 16 through 20.
“Black children and young adults had lower rates of ALL, the most common childhood leukemia, at every age, but this decreased risk was most striking among children ages 2 to 5, where the ALL incidence among Black children was less than half that of White children,” said Dr. Marcotte.
The researchers also observed that although Black children experienced the same incidence of non-Hodgkin lymphoma as White children, Black young adults were at higher risk than White young adults, beginning at age 28. Black children were also at higher risk for nephroblastoma, a rare kidney tumor typically diagnosed before age 5.
Hispanic children had a higher risk of Hodgkin lymphoma than White children at ages 0 to 9 years but had a lower risk at all other ages. They also had lower rates of astrocytoma, a cancer of the brain or spinal cord, but higher rates of ALL, especially at ages 10 through 23.
The analysis also revealed that Asian and Pacific Islanders, American Indian, and Alaskan Natives have lower rates of many types of childhood cancer.
“Some of the patterns we observed may be due to racial and ethnic differences in known childhood cancer risk factors, such as exposure to infections and congenital anomalies,” said Dr. Marcotte. “We also know that the causes of each type of childhood and young adult cancer may vary depending on the age at which it occurs. For instance, exposure to Epstein-Barr virus is associated with Hodgkin lymphoma diagnosed in children younger than age 10, but not at older ages…. Thus, Epstein-Barr virus exposure may explain the higher risk of Hodgkin lymphoma among Hispanic children younger than age 10.”
Dr. Marcotte and colleagues hope this work will play a role in reducing racial and ethnic disparities in cancer risk among children and young adults.
Disclosure: For full disclosures of the study authors, visit acsjournals.onlinelibrary.wiley.com.
