Profile of neuroblastoma detected by mass screening, resected after observation without treatment: results of the Wait and See pilot study

Neuroblastoma (NB) detected by mass screening (MS) usually shows favorable prognosis and sometimes regresses spontaneously. Therefore, the authors started an observation program for these patients to avoid overtreatment. In this study, the authors analyzed the profile of NB resected after observation to elucidate the nature of NB detected by MS. Between 1994 and 2004, 22 NB patients matched the following criteria and entered the observation program after obtaining informed consent: stage I or II, less than 5 cm in diameter, and without involvement of large vessels or organs. If increase in size, elevation of tumor markers, or evidence of metastasis was observed, the tumor was immediately resected. Thirteen (59%) of 22 cases showed spontaneous regression. In the remaining 9 cases, tumors were resected because of parents' request, increase in size, and/or elevation of tumor markers. Four tumors had at least one unfavorable biologic feature, and 3 of them had more than 2. According to Shimada's system, 2 had unfavorable histology. One was diploid tumor, 3 had 1p deletion, and Trk-A expression was low in 4 tumors. All patients survived without evidence of recurrence. The observation program has shown that at least one third of the NB detected by MS regressed spontaneously. On the other hand, MS may detect some cases with unfavorable tumor in early stage, which benefit from screening.