Background: Childhood cancer is a public health problem in Thailand. Improving clinical knowledge and increasing treatment intensity that may lead to complications could improve outcomes. Recently, the five-year survival rates have been increasing worldwide. However, the knowledge of long-term consequences still lacks.

Objective: To assess the intelligence quotient (IQ) of childhood cancer survivors compared with their siblings and exploring the risk factors of impaired cognitive outcomes of the survivors.

Materials and Methods: Cancer survivors, treated at Ramathibodi Hospital and in remission for more than three years were enrolled. The subjects with neurodevelopmental disorder or cranial irradiation were excluded. Their siblings were enrolled as controls. The Children’s IQ were measured using the Wechsler Intelligence Scale for Children Third Edition (WISC-III).

Results: One hundred and three cancer survivors and thirty-seven healthy siblings were enrolled. The mean age of all participants was 11 years old. The cancer survivors had significant lower IQ score than the control. The low socioeconomic status (SES) and the parents’ education below grade 9 were significant factors causing the childhood cancer survivor group to have significantly lower IQ score than the controls.

Conclusion: Children treated with chemotherapy had decreased neurocognitive outcomes. In addition, lower SES and lower parental education were significant factors resulting in impaired intelligence.

Keywords: Childhood cancer survivors, Intelligence quotient, Socioeconomic status, Parental education

Received 15 Mar 2018 | Revised 22 Apr 2019 | Accepted 23 Apr 2019