Table 3.

Analysis of factors for tumor progression.

Variable	Categorization	Tumor progression (TP)
		n a	Events	p b
Pathologic data
Tumor stage (WHO 1973c)	pTa	90	10	0.360
	pT1	68	12
Histologic grade (WHO 1973c)	G1	44	3	0.085
	G2	86	12
	G3	28	7
Histologic grade (WHO 2004d)	Low grade	99	10	0.083
	High grade	59	12
Adjacent carcinoma in situ	No	146	20	0.545
	Yes	12	2
Multifocality	Unifocal tumor	115	15	0.465
	Multifocal tumor	43	7
Growth pattern	Papillary	151	17	<0.0001
	Solid	7	5
Immunohistochemistry
CD73	Score 0 or 1+	114	20	0.030
	Score 2+	44	2
Ki-67 labelling index	≤10%	106	9	0.003
	>10%	52	13

^aOnly primary pTa and pT1 tumors are included.

^bLog-rank test (2-sided); bold face representing p values <0.05.

^cStaging and grading according to the 1973 WHO classification system.

^dStaging and grading according to the 2004 WHO classification system.