HEALTH PROFESSIONAL · SOURCE READING
Observation with or without biopsy
Source: Neuroblastoma Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: April 28, 2025 · Captured 2026-09-09.
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Observation without biopsy has been used to treat perinatal neuroblastoma with small adrenal tumors.
A COG study determined that selected small INSS stage 1 or stage 2 adrenal masses, presumed to be neuroblastoma, detected in infants younger than 6 months by screening or incidental ultrasonography, may safely be observed without obtaining a definitive histological diagnosis and without surgical intervention. This technique avoids potential complications of surgery in newborn patients.[4] Patients are observed frequently to detect any tumor growth or spread, indicating a need for intervention. Additional studies, including an expansion of criteria allowing observation without surgery, are under way in the COG ANBL1232 (NCT02176967) study (closed to accrual).
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Evidence (observation without biopsy):
The COG-ANBL00P2 (NCT00445718) study reported that expectant observation is safe in patients younger than 6 months with solid adrenal tumors smaller than 3.1 cm (or cystic tumors smaller than 5 cm) and INSS stage 1 disease.[4]
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The COG-ANBL00P2 (NCT00445718) study reported that expectant observation is safe in patients younger than 6 months with solid adrenal tumors smaller than 3.1 cm (or cystic tumors smaller than 5 cm) and INSS stage 1 disease.[4]
Sixty-seven of 83 patients (81%) demonstrated spontaneous regression and avoided surgical intervention.
The COG-ANBL00P2 (NCT00445718) study reported that expectant observation is safe in patients younger than 6 months with solid adrenal tumors smaller than 3.1 cm (or cystic tumors smaller than 5 cm) and INSS stage 1 disease.[4]
Eighty-three of 87 eligible patients were observed without biopsy or resection; only 16 patients (19%) ultimately underwent surgery.
The COG-ANBL00P2 (NCT00445718) study reported that expectant observation is safe in patients younger than 6 months with solid adrenal tumors smaller than 3.1 cm (or cystic tumors smaller than 5 cm) and INSS stage 1 disease.[4]
The 3-year EFS rate for a neuroblastoma event was 97.7%, and the OS rate was 100%.
Controversy exists about the need to attempt resection, at the time of diagnosis or later, in asymptomatic infants aged 12 months or younger with apparent stage 2B and stage 3 MYCN-nonamplified and favorable-biology disease. In a German clinical trial, some of these patients were observed after biopsy or partial resection without chemotherapy or radiation therapy. Many patients did not progress locally and never underwent a first or additional resection.[5] In the COG ANBL1232 (NCT02176967) study (closed to accrual), infants younger than 18 months who have L2 tumors with favorable biology are being observed after tumor biopsy.
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