One hundred neuroblastomas detected through a mass screening system in Japan

In Japan, a nationwide mass screening (MS) program for preclinical detection of neuroblastoma in infants was done by measuring urinary vanillylmandelic acid and homovanillic acid at the age of 6 months. In this study, clinical, histopathologic, and biologic features of 100 neuroblastomas detected through the Japanese MS are presented.

Clinical data of the MS cases were collected and histologic and biologic studies performed on the surgically resected neuroblastomas. Histopathologic evaluation was done including the Shimada classification (all tumors), N-myc oncogene status (58 tumors), and ploidy analysis (31 tumors). The serum ferritin level was measured before surgical intervention in 27 cases.

The primary tumor sites of these cases were adrenal (69), retroperitoneum (21), and mediastinum (10). The tumors were clinical Stage I (31), II (31), III (19), IV (8), and IV-S (9); two children had bilateral primary adrenal tumors. Ninety-three percent (93/100) had favorable histology; 100% (58/58) had nonamplified N-myc oncogene expression; 81% (25/31) showed a favorable ploidy pattern, and 96% (26/27) had normal serum ferritin levels. To date, all children in this series are alive and well, although a total of 13 tumors were associated with one or two poor risk factors; 6 had unfavorable histology (UH), 5 had an unfavorable ploidy (UP) pattern, one had UH and UP, and one had an elevated ferritin level.

The majority of neuroblastomas detected through the MS showed favorable biologic factors (biologically favorable group). However, there was a small group with histopathologic and/or biologic unfavorable factors. Patients with unfavorable factors apparently benefit most from early surgical intervention.