Results of mass screening for neuroblastoma in 18-month-old infants in Osaka area, Japan.

PURPOSE: In 2004, the Japanese government halted nationwide mass screening for neuroblastoma in 6-month-old infants as it led to overdiagnosis of localized tumors with favorable prognoses and failed to reduce neuroblastoma-related mortality. However, a new mass screening program for neuroblastoma in 18-month-old infants (18MS) was conducted in the Osaka prefecture. We assessed the efficacy of the 18MS in screening unfavorable cases. METHODS: Public health centers in Osaka prefecture, excluding the Osaka city area, provided test kits to the guardians of infants who received a check-up at 18 months of age between 2004 and 2017. For patients whose standardized urinary levels of vanillylmandelic acid or homovanillic acid exceeded the threshold, they were further examined and treated in two specific hospitals Osaka University Hospital and Osaka Women's and Children's Hospital. Screening-positive patients with and without neuroblastoma were retrospectively reviewed. RESULTS: Among 142,423 children screened during the 18MS, 85 tested positive, and 14 were diagnosed with neuroblastoma. Twelve patients were classified as very low risk, while 2 were classified as high risk, based on the International Neuroblastoma Risk Group risk classification. CONCLUSION: The 18MS did not screen unfavorable cases with neuroblastoma efficiently, although few participants benefited from it.