Stage      Criteria

IA           Localized melanoma    0.75mm or level 2* (T1,  N0,  M0)
IB           Localized melanoma 0.76mm to 1.5mm or level 3* (T2,  N0,  M0)
IIA         Localized melanoma 1.6mm to 4mm or level 4* (T3,  N0,  M0)
IIB         Localized melanoma    4mm or level 5* (T4,  N0,  M0)
III          Limited nodal metastases involving only one regional lymph node basin
              (area),  or fewer than 5 intransit metastases but without nodal metastases
              (any T,  N1,  M0)
IV          Advanced regional metastases (any T,  N2,  M0) or any patient with distant
              metastases (any T,  any N,  M1 or M2)


*  When the thickness and level of invasion criteria do not coincide with a T classification,
thickness should take precedence.