Patients with localized respectable neuroblastoma (stage 1) have excellent event-free survival (EFS) rates with surgical excision of tumor only. Adjuvant chemotherapy is generally not needed for this group of patients. Even the presence of residual microscopic disease does not significantly affect the EFS. If patients develop recurrent disease, chemotherapy can be used, and the overall survival rate remains higher than 95%.
Similar therapy is offered to patients with stage 2A/2B disease who are presently assigned to a low-risk category if they have MYCN -non amplified tumors, regardless of age histology or ploidy. Patients with stage 2A/2B disease with amplified MYCN are considered high risk regardless of age and histology.
A study by the Pediatric Oncology Group of experience with conservative treatment of low-risk patients confirmed the excellent outcomes for these patients with surgery alone. However, overall survival seemed lower among patients with stage 2b, MYC-N nonamplified, unfavorable histology or diploid tumors; thus, in the future, this specific group of patients may require reconsideration of their risk categorization. [20]
Most patients with 4S disease (ie, non-MYCN –amplified tumors, favorable histology, hyperdiploid tumors in infants younger than 1 y) are also considered to be in the low-risk group and most experience spontaneous regression. Thus, observation or surgery alone is often all that is needed to manage these tumors. Chemotherapy may be used to control life-threatening situations such as respiratory distress or mechanical obstruction.
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Histologic subtypes of neuroblastoma. Top right panel, neuroblastoma: A monotonous population of hyperchromatic cells with scant cytoplasm. Bottom left panel, ganglioneuroblastoma: Increased schwannian stroma. Bottom right panel, ganglioneuroma: Mature ganglion cell with schwannian stroma.
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CT scan of abdomen in a patient with a retroperitoneal mass arising from the upper pole of the left kidney and elevated urine catecholamines.
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MRI of a left adrenal mass. The mass was revealed by fetal ultrasonography at 30 weeks' gestation. During infancy, the mass was found on the inferior pole of the left adrenal and was completely resected. Before surgery, the metastatic workup was negative. Surgical pathology service confirmed a diagnosis of neuroblastoma. After 3 years of follow-up care, no recurrence was observed.
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A one-week-old neonate had abdominal ultrasonography for evaluation of projectile vomiting. A right adrenal mass (100% cystic) was an incidental finding. Evaluation of the mass by CT was consistent with an adrenal bleed (3.6 x 3.1 x 2.4 cc). The infant was followed at 2 weeks (2-dimensional size diminished to 1.5 x. 2.4 cm2 on ultrasonography) and then at 6 weeks to document that the adrenal bleed continued to involute. Urine catecholamines were normal.
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Table. A Consensus Pretreatment Classification schema by the International Neuroblastoma Risk Group (INRG). This schema is based in the INRG stage, age, histologic category, tumor grade of differentiation, MYCN sastus, 11q-aberrations and DNA ploidy. A combination of these characteristics results in four risk groups noted in the last column: very low, low, intermediate and high risk, with the following 5 year EFS: >85%, >75%-85%, >50%-75%, and < 50%. These risk groups are distributed among the different stages and labeled alphabetically from A to R (without letters L and M to avoid confusion with the INRG stage notation). Notations in the table are as follow: L1, localized tumor confined to one body compartment; L2, locoregional tumor with presence of one or more risk factors defined radiologically; M, distant metastatic disease (except stage MS); MS, metastatic disease confined to skin, liver and/or bone marrow in children < 18 months of age. GN, ganglioneuroma; GNB, ganglioneuroblastoma; Amp, amplified; n/amp, not amplified. (Adapted from The International Neuroblastoma Risk Group (INRG) Classifications System: An INRG Task Force Report by Cohn, et al. Journal of Clinical Oncology 27(2):289-297, 2009).
