Risk of cancer in children, adolescents, and young adults with autistic disorder.

OBJECTIVES: To investigate whether individuals with autism have an increased risk for cancer relative to the general population.

STUDY DESIGN: We enrolled patients with autistic disorder from the Taiwan National Health Insurance database in years 1997-2011. A total of 8438 patients diagnosed with autism were retrieved from the Registry for Catastrophic Illness Patients database. The diagnosis of cancers was also based on the certificate of catastrophic illness, which requires histological confirmation. The risk of cancer among the autism cohort was determined with a standardized incidence ratio (SIR).

RESULTS: During the observation period, cancer occurred in 20 individuals with autism, which was significantly higher than a total number of expected cancers with a SIR estimate of 1.94 (95% CI 1.18-2.99). The number of cancer in males was greater than the expected number with a SIR of 1.95 (1.11-3.16), but no excess risk was found for females with a SIR of 1.91 (0.52-4.88). Cancer developed more than expected in individuals age 15-19 years with the SIR of 3.58 (1.44-7.38), but did not differ in other age range groups. The number of cancers of genitourinary system was significantly in excess of the expected number (SIR 4.15; 95% CI 1.13-10.65), and increased risk was found in ovarian cancer with SIR of 9.21 (1.12-33.29).

CONCLUSIONS: Our study demonstrated that patients with autistic disorder have an increased risk of cancer.