Stages and Grades of Neuroblastoma


Staging for neuroblastoma is performed according to the International Neuroblastoma Risk Group System (INRGSS) in parallel with the old International Neuroblastoma Staging System (INSS) classification system. Neuroblastoma can be classified into Stage 1, Stage 2A, 2B, Stage 3, and Stage 4, 4S.


The International Neuroblastoma Risk Group System (INRGSS) was published in 2008 as a novel method of stratifying patients before surgery​1​. This system is currently used in parallel with the old International Neuroblastoma Staging System (INSS). There are several important differences between INRGSS and INSS. First, while INSS targeted the postoperative stage, INRGSS emphasises pretreatment risk stratification based on diagnostic criteria and Image-Defined Risk Factors (IDRF).

Stages of Neuroblastoma (NBL)

Stage 1

Localised tumours with or without microscopic residual disease; representative ipsilateral lymph nodes are microscopically negative for tumours (i.e., nodules attached to the primary tumour may be positive).

Stage 2A

  • Local tumour with incomplete total resection.
  • Presence of non-adherent lymph nodes that are microscopically negative for tumours.

Stage 2B

  • Local tumours with or without complete resection.
  • Presence of ipsilateral non-adherent lymph nodes that are benign for the tumour.
  • The enlarged contralateral lymph node should be microscopically negative.

Stage 3

  • Unilateral infiltrating midline tumours with or without the involvement of regional lymph node; or 
  • Localised unilateral tumour with involvement of contralateral regional lymph node; or
  • Bilateral extension with tumour midline infiltration (non-surgical); or 
  • Involvement of lymph nodes.

The midline is defined as the vertebral column. Tumours that start on one side and cross the midline should infiltrate contralateral or posterior to the spine.

Stage 4

Presence of any primary tumour that has spread to distant lymph nodes, bone marrow, bone, skin, liver, and/or organs other than those defined in Stage 4S.

Stage 4S

Locally primary tumour, defined in Stage 1, 2A, or 2B, with limited spread to the liver, skin, and/or bone marrow (by definition only in infants under 12 months of age). Marrow involvement should be kept minimal (i.e., <10% of total nuclear cells confirmed as malignant after bone marrow aspiration or bone biopsy). More significant involvement of the bone marrow is considered stage IV disease. If an MIBG scan is performed, it should be negative for bone marrow disease​2​.


  1. 1.
    Monclair T, Brodeur G, Ambros P, et al. The International Neuroblastoma Risk Group (INRG) staging system: an INRG Task Force report. J Clin Oncol. 2009;27(2):298-303. doi:10.1200/JCO.2008.16.6876
  2. 2.
    Taggart D, London W, Schmidt M, et al. Prognostic value of the stage 4S metastatic pattern and tumor biology in patients with metastatic neuroblastoma diagnosed between birth and 18 months of age. J Clin Oncol. 2011;29(33):4358-4364. doi:10.1200/JCO.2011.35.9570