Childhood cancer incidence rates outside major U.S. metropolitan statistical areas (MSAs), 1999-2022: A CDC WONDER descriptive analysis.

BACKGROUND: Rural-urban disparities in cancer outcomes are well documented, but pediatric data remain limited. Prior research has established broad age-specific incidence patterns for childhood cancers, yet few focus specifically on children outside of metropolitan areas. METHODS: Using CDC Wonder data, we compare invasive childhood cancer incidence rates among children rising outside major metropolitan statistical areas (MSAs) overall and by major subtypes across five age groups: < 1, 1-4, 5-9, 10-14, and 15-19 years) with benchmark estimates from children rising within major MSAs. We also evaluated temporal trends (1999-2022) overall and for the five most common subtypes (leukemias, lymphomas, CNS, SNS, and renal) for children outside major MSAs. RESULTS: From 1999-2022, overall cancer incidence for children outside major MSAs increased from 149.7 to 180.5 cases per million, with a temporary decline in 2020 followed by a rebound through 2022. Overall incidence for this group followed a U-shaped age distribution, peaking in infancy (252.3 per million), low at ages 5-9 years (121.5 per million), and increasing again in late adolescence (215.5 per million). Leukemias peaked in ages 1-4, lymphomas increased steadily with age, and CNS tumors were most common in younger children. Embryonal tumors were concentrated in infancy and declined thereafter, while bone tumors, carcinomas, and germ cell tumors increased with age. DISCUSSION: Pediatric cancer incidence patterns outside major MSAs trend similarly to previously described broader pediatric trends. Overall incidence rates were slightly lower among the youngest children outside major MSAs compared with major MSA benchmarks, but further research is needed to understand potential geographic differences in pediatric cancer incidence.