Background: In Japan, mass screening for neuroblastoma has been performed at 6 months of age to improve the prognosis of this condition for more than 20 years. In recent years, most neuroblastomas detected by mass screening were considered to have favorable biological features and sometimes tend to regress spontaneously.
Methods: The authors established non-treated observation criteria in 1997 and criteria for observation of residual tumor after first-line chemotherapy in 1999, and have made an effort to reduce the intensity of medical treatment for neuroblastoma. The authors examined outcomes of 79 patients who were found in the Shizuoka neuroblastoma mass screening at 6 months of age and who received medical treatment or underwent observation in Shizuoka Children’s Hospital, Shizuoka, Japan, between December 1981 and December 2004.
Results: A total of 77 patients survived but the remaining two patients died from complications of medical treatment. None of the patients died due to progression of neuroblastoma. In the cases, non-treated observation was performed in 17. Of those, 12 patients are now under non-treated observation. Of their tumors, two have disappeared, nine have become smaller and another one has not change in size. Observation of residual tumor after first-line chemotherapy was performed in 15 cases, and three disappeared and the other 12 cases became smaller. Medical treatment-related complications were observed in 20 of 67 patients who received medical treatment, and 18 of the 20 patients were seen before establishing non-treated observation criteria.
Conclusion: Non-treated observation and observation of residual tumor after first-line chemotherapy were useful to reduce medical treatment-related complications.