Table 6. Children's Oncology Group (COG) Neuroblastoma Low-Risk Group Assignment Schema Used for COG-P9641 and COG-A3961 Studiesa continued...
Standard treatment options for low-risk neuroblastoma include the following:
- Observation without biopsy (for infants younger than 6 months and disease limited to the adrenal gland that is less than 3 cm in diameter).
- Chemotherapy (for symptomatic disease or unresectable progressive disease after surgery).
Treatment for patients categorized as low risk (refer to Table 6) may be surgery alone, which is curative for most patients with low-risk neuroblastoma. Patients need not undergo complete resection of disease to be cured by surgery alone..
There is controversy about the need to attempt resection, whether at the time of diagnosis or later, in asymptomatic infants aged 12 months or younger with apparent stage 2B and 3 MYCN-nonamplified disease. In a German clinical trial, some of these patients were observed after biopsy or partial resection without chemotherapy or radiation, and many did not progress locally and never received additional resection.
Observation without biopsy
Studies suggest that selected small adrenal masses, presumed to be neuroblastoma, detected in infants younger than 6 months by screening or incidental ultrasound may safely be observed without obtaining a definitive histologic diagnosis and without surgical intervention, thus avoiding potential complications of surgery in the newborn.
Evidence (observation without biopsy):
- COG-ANBL00P2 reported that expectant observation is safe, with 81% of patients demonstrating spontaneous regression while avoiding surgical intervention.
- Eighty-three of 87 eligible patients were observed without biopsy or resection and only 16 (19%) ultimately underwent surgery.
- Three-year EFS (for a neuroblastoma event) was 97.7% and OS was 100%.
Results from the COG-P9641 study showed that surgery alone, even without complete resection, can cure nearly all patients with stage 1 neuroblastoma, and the vast majority of patients with asymptomatic, favorable biology, INSS stage 2A and 2B disease. The use of chemotherapy may be restricted to specific situations (e.g., children with MYCN-amplified stage 1 and 2 neuroblastoma and children with MYCN-nonamplified stage 2B neuroblastoma who are older than 18 months or who have unfavorable histology or diploid disease). These children have a less favorable outcome than other low-risk patients.[2,5]