Table 3.

The P values for statistical comparisons of size of BIDC among N stages

N stages	AREA	Tumor Width	Tumor Depth
N0 vs. N1-3	< 0.0001a,b	< 0.0001a,b	< 0.0001a,b
N1 vs. N2	0.511	0.760	0.258
N1 vs. N3	< 0.0001a,b	< 0.017a,b	< 0.0001a,b
N2 vs. N3	0.001a,b	0.041	0.005
N0-1 vs. N2-3	< 0.0001a,b	0.007	< 0.0001a,b
N0-2 vs. N3	< 0.0001a,b	0.001	< 0.0001a,b

Note: Statistical analysis was done with Mann-Whitney test.

^a P < 0.05.

^b P < 0.05 after Bonferroni correction.