Table 7.

Postoperative recurrence rates and hazard ratios in high- and low-grade groups at stage IA

	Crude recurrence rate % [No.]	Hazard ratio [95% CI]
Cut-off 71.5%	P = 0.022	P = 0.002
Low -grade group [116]	3.4 [4]	1.00 [ref.]
High-grade group [13]	23.1 [3]	7.35 [1.64- 33.0]
Cut-off 9.5%	P = 0.058	P = 0.041
Low -grade group [66]	1.5 [1]	1.00 [ref.]
High-grade group [63]	9.5 [6]	6.72 [0.81- 55.79]

ARC-CLSTs, clusters based on architectural elements; No., number of cases; P, P value for crude reccyrrence rate and harad ratio are calculated by Fisher's exact test and and Log-rank test, respectively; CI, confidence interval; ref., reference; N.A., not available