How to deal with advanced cases of neuroblastoma detected by mass screening: A report from the pediatric oncology study group of the Kyushu area of Japan☆

Abstract Since 1985, a nationwide program of mass screening (MS) for neuroblastoma has been underway for 6-month-old infants throughout Japan. As a result, the number of patients with stage I or II disease has obviously increased, and this has resulted in overall improvement of the prognosis for neuroblastoma. Some cases detected by MS were already in an advanced stage and have also had a good prognosis. In such cases, no definitive treatment protocol has been developed. Therefore, the authors investigated (1) the clinical and biological features of the advanced neuroblastoma cases detected by MS and (2) the best way to deal with such cases. The authors analyzed 94 cases of advanced-stage neuroblastoma registered in the Kyushu area (population, 15 million) between 1985 and 1990. Eighteen cases (16 stage III, 2 stage IV) were found by MS, and the others (23 stage III, 53 stage IV) were diagosed clinically. The following results were obtained: (1) No N- myc amplifications were observed in cases detected by MS, whereas 16 of the 45 examined patients in the non-MS group had high amplifications of N- myc . (2) With regard to Shimada's classification, DNA content, and S-100 protein positivity, most of the advanced tumors found by MS showed characteristics indicating a good prognosis. (3) The 5-year survival rate for the non-MS group is less than 25%, whereas all of the patients whose tumors were detected by MS are alive, even after undergoing mild chemotherapy. Thus, the authors conclude that the cases of advanced neuroblastoma detected by MS are a unique population that possess characteristics that generally indicate a good prognosis, and therefore aggressive chemotherapy might be unnecessary in such cases.