Staging

The International Neuroblastoma Staging System (INSS) is a primarily surgical staging system where staging depends on the aggressiveness of the surgical approach utilised: (1)

Stage 1: localised tumour with complete gross excision, with or without microscopic residual disease; representative ipsilateral lymph nodes negative for tumour microscopically (nodes attached to and removed with the primary tumour may be positive).

Stage 2a: localised tumour with incomplete gross excision; representative ipsilateral non-adherent lymph nodes negative for tumour microscopically.

Stage 2b: localised tumour with or without complete gross excision; with ipsilateral non-adherent lymph nodes positive for tumour; enlarged contralateral lymph nodes must be negative microscopically.

Stage 3: unresectable unilateral tumour infiltrating across the midline (beyond the opposite side of the vertebral column) with or without regional lymph node involvement, or localised unilateral tumour with contralateral regional lymph node involvement, or midline tumour with bilateral extension via infiltration (unresectable) or lymph node involvement.

Stage 4: any primary tumour with dissemination to distant lymph nodes, bone, bone marrow, liver, skin, and/or other organs (except as defined for stage 4S disease).

Stage 4S: localised primary tumour (as defined for stage 1, 2A, or 2B disease), with dissemination limited to skin, liver, and/or bone marrow (limited to infants <1 year of age, marrow involvement <10% of total nucleated cells, 123-iodine-metaiodobenzylguanidine [MIBG] scan findings negative in the marrow).

Note

The International Risk Group Staging System (INRGSS) has since been developed to define homogeneous, pre-treatment patient cohorts to facilitate accurate comparison in risk-based clinical trials. Clinical and biological factors are combined to define low, intermediate, high (4 groups) based on image-defined risk factors (IDRFs). These IDRFs are determined at the time of diagnosis, prior to surgery. (2)

Patients are divided into four main categories:

L1: localised tumour not involving vital structures, as defined by the list of IDRFs (below), and confined to one body compartment

L2: local-regional tumour with presence of one or more IDRFs

M: distant metastatic disease (except stage MS tumour)

MS: metastatic disease in children younger than 18 months, with metastases confined to the skin, liver, and/or bone marrow

Reference

1. Brodeur GM, Pritchard J, Berthold F, et al. Revisions of the international criteria for neuroblastoma diagnosis, staging, and response to treatment. J Clin Oncol. 1993 Aug;11(8):1466-77.
2. Cohn SL, Pearson AD, London WB, et al; The International Neuroblastoma Risk Group (INRG) classification system: an INRG J Clin Oncol. 2009 Jan 10;27(2):289-97.