Introduction: Childhood cancer is rare, and the rate at which new cases develop among children(incidence) is 15.3 per 100,000 per year, which corresponds roughly to 1 in 6,500children and adolescents under age 20 . Genetic factors and certain prenatal (e.g., radiation, diethylstilbestrol [DES]) and postnatal exposures (radiation, viruses) are known to increase the risk of developing some childhood cancers, but for most cases of childhood cancer, the cause remains unknown. Childhood cancers are classified primarily by histology into 12 major categories using the International Classification of Childhood Cancers (ICCC). Our goal was to describe current childhood cancer incidence in the Iran and identify demographic and geographic variation among children and adolescents with cancer.
Methods: We examined data from 5 National children and adolescent’s hospital, Epidemiology, and End Results state-wide registries (representing >50% of the Iran population) to identify cancers diagnosed among persons aged 0 to 19 from 2010–2012. Diagnosed cancers were grouped by the third version of the International Childhood Cancer Classification. Analyses were stratified according to gender, age, and race, ethnicity, and Iran census region. A multivariable negative binomial regression model was used to evaluate demographic and geographic differences in incidence for all cancers combined.
Results: We identified 651 cases of childhood cancer with an age-adjusted incidence rate of 112.92 per million. Stratified analyses showed that, for all cancers combined, boys had a significantly higher rate than girls; children (aged 0–14 years) had a significantly lower rate than adolescents (aged 15–19 years); and Kurd children had the highest incidence rate among all races. Young people living in the Kurdistan province regions, which may be partially attributed to significantly higher incidence rates for central nervous system neoplasms and lymphomas in this region compared with other Iran census regions. Negative binomial regression analysis demonstrated that the childhood cancer-incidence rate varied significantly according to gender, age, race, ethnicity, and geography.
Conclusion: This study is the first to demonstrate substantial regional differences in the incidence of childhood cancer. It also shows that incidence varies according to gender, age, race, and ethnicity. Our research findings are useful for prioritizing future childhood cancer research needs.
Keywords: Children Cancer, Adolescent, Cancer incidence, Iran cancer