SPONTANEOUS REGRESSION OF LOCALIZED NEUROBLASTOMA DETECTED BY MASS-SCREENING

Purpose: To clarify whether and when neuroblastomas identified through screening do regress, and to ascertain how to treat them appropriatel y, we observed screened patients who had localized tumors, without any therapeutic intervention. Patients and Methods: The criteria for the observation program were as follows: disease stage I or II; tumor less than 5 cm in diameter; no invasion to the intraspinal canal or growth to the great vessels; urinary vanillylmandelic acid (VMA) and homovan illic acid (HVA) less than 50 mu g/mg creatinine; and informed consent . Of 25 patients identified through screening for 6-month-old infants in Saitama Prefecture, Japan between April 1994 and March 1996, 11 pat ients who met the criteria and one other patient with stage III tumor were enrolled onto the program. They were examined by abdominal ultras onography (US) and their urinary VMA and HVA levels were assessed appr oximately once per month. The observation periods ranged from 4 to 27 months. Results: The Il tumors decreased in size, although one of thes e 11 tumors initially enlarged until the patient was 12 months of age and decreased in size thereafter. One other tumor slightly increased i n size. Urinary VMA levels decreased in all patients. None of the tumo rs had completely disappeared by the last observation day. Conclusion: Our results suggest that regression of screened neuroblastoma is not a rare phenomenon. At present, it seems reasonable to adopt a wait-and -see strategy, with careful observation, for selected stage I or II tu mors identified in infants screened at 6 months of age. (C) 1998 by Am erican Society of Clinical Oncology.