Comparative clinical studies were made between 23 cases of neuroblastoma treated before the initiation of mass screening test (pre-screening group) and 21 cases treated thereafter (post-screening group). The post-screening group included 12 cases, discovered by the screening at the average age of 8-month-old. Age distribution at diagnosis showed two peaks at the age of 2 and 4-year-old in the pre-screening group and single big peak of less than one-year-old in the post-screening group. Predominant stage by the Japanese Staging of Pediatric Surgeons' Society was IV (70%) in the pre-screening and I (33%) and III (43%) in the post-screening. No gross difference was noted between the two groups as to the site of origin. Resectability (equivalent to PS-I, II and Ilia by UICC classification) and 2 years survival rate were remarkably improved in the post-screening group, from 13% to 57 and from 26% to 76% respectively. Thus, valuableness of our screening system, using urinary VMA and HVA measurement by HPLC was stressed. The disease was detected at the incidence of one out of 5,200 examined infants.
