Table 1.

Different HB staging criteria for children with the disease

Stage	Phasing criteria
The PRETEXT preoperative typing system
Stage I	Tumor confined to 1 liver segment, no tumor invasion in 3 adjacent liver segments
Stage II	The tumor involved 2 liver segments and the other 2 adjacent liver segments were not invaded by the tumor.
Stage III	The tumor involves 2 liver segments and the other 2 non-contiguous liver segments are not involved; or the tumor involves 3 liver segments.
Stage IV	The tumor involved 4 liver segments.
Annotation factors	P (portal invasion)
	V (hepatic vein/vessel invasion)
	F (multifocality)
	E (extrahepatic tumor extension)
	R (tumor rupture)
	M (distant metastasis)
The postoperative COG Evans staging system
Stage I a	Complete resection of the tumor, histopathologic type of simple fetal type
Stage I b	Complete resection of tumor, histopathological types other than simple fetal type
Stage II	Tumor largely resected, with microscopic remnants
Stage III	Tumor with visual remnants, or basic resection with positive lymph nodes, or tumor rupture or peritoneal hemorrhage
Stage IV	Occurrence of distant metastases at diagnosis, regardless of complete resection of the primary lesion