Nationwide trends in childhood cancer incidence and survival in Iran: analysis of national cancer registry data, 2005-2014.

[BACKGROUND] Childhood cancer poses a growing global health burden. This study aimed to assess incidence patterns, temporal trends and five-year survival probabilities of childhood cancers in Iran using national cancer registry data from 2005 to 2014.

[METHODS] A retrospective analysis was conducted using data from the Iran National Cancer Registry. After quality control procedures, 20,624 validated cases of childhood cancer (ages 0-14 years) were included. Age-standardized incidence rates (ASIRs) were calculated per million person-years using the new World Health Organization standard population. Trends over time were examined, and five-year observed survival probabilities were estimated for major diagnostic categories according to the International Classification of Childhood Cancer, Third Edition.

[RESULTS] The overall ASIR for childhood cancers in Iran was 116.2 per million person-years, higher in males (128.1) than in females (103.6). The most common cancer groups were leukemia (ASIR: 31.7), lymphomas (ASIR: 13.2), and central nervous system neoplasms (ASIR: 12.6). Lymphoid leukemia was the most frequent subtype (ASIR: 26.6 in males, 20.0 in females). Joinpoint analysis indicated a modest but significant increase in overall ASIRs in both sexes (average annual percent change ≈ 3.5%), driven mainly by central nervous system and hepatic tumors, while retinoblastoma and Hodgkin lymphoma declined. The overall five-year survival was 81.0%, improving from 70.2% in 2005-2009 to 81.4% in 2010-2014. The highest survival was observed in lymphomas (97.1%), followed by retinoblastoma (96.9%), and soft tissue sarcomas (90.7%), while the lowest was found in neuroblastoma (39.1%). Children aged 0-4 years had the lowest survival (79.6%), compared with 82.9% and 82.0% in those aged 5-9 and 10-14 years, respectively.

[CONCLUSIONS] This nationwide study presents a comprehensive analysis of childhood cancer incidence and survival in Iran. The findings indicate a gradual increase in incidence, particularly among boys and younger children. Survival appears to have improved over time, though variations by age and cancer type warrant cautious interpretation due to differences in follow-up and case mix. These findings highlight progress in pediatric oncology in Iran and underscore the importance of strengthening cancer registration, diagnostic capacity, and equitable access to specialized care to further improve outcomes for children with cancer.