Table 1.

The international neuroblastoma staging system

Stage	Tumour characteristics
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, with or without regional lymph node involvement; or localised unilateral tumour with contralateral regional lymph node involvement; or midline tumour with bilateral extension by infiltration or lymph node involvement
Stage 4	Any primary tumour with dissemination to distant lymph nodes, bone, bone marrow, liver, and/or other organs (except as defined for stage 4s)
Stage 4s	Localised primary tumour (as defined for stage 1, 2A, or 2B), with dissemination limited to liver, skin, and/or bone marrow (limited to infants <1 year of age)