Table 1.

Sample size calculations for phase II

5-year DFS rate		Non-inferiority threshold value HR	Power	N	Number of cases required	Interim analysis					Total cases assuming 20% missing follow-up rate
Laparotomic group	Non-inferiority threshold value					Times of analysis	Time points of analysis	Threshold value	Nominal α (bilateral)	Cumulative power
0.85	−0.08	1.6082	0.9	1529	443	1	148	2.27943	0.022642	0.394137	1912
						2	296	2.29488	0.02174	0.731679
						Final	443	2.29588	0.021683	0.900083
0.85	−0.08	1.6082	0.8	1158	336	1	112	2.27943	0.022642	0.298272	1448
						2	224	2.29488	0.02174	0.601534
						Final	336	2.29588	0.021683	0.800055
0.8	−0.08	1.4722	0.9	1352	324	1	108	2.27943	0.022642	0.3942	1692
						2	216	2.29488	0.02174	0.731754
						Final	324	2.29588	0.021683	0.900132
0.8	−0.08	1.4722	0.8	1024	246	1	82	2.27943	0.022642	0.298337	1280
						2	164	2.29488	0.02174	0.601635
						Final	246	2.29588	0.021683	0.800144
0.75	−0.08	1.3921	0.9	1131	215	1	72	2.27943	0.022642	0.394035	1416
						2	144	2.29488	0.02174	0.731558
						Final	215	2.29588	0.021683	0.900004
0.75	−0.08	1.3921	0.8	857	163	1	55	2.27943	0.022642	0.298344	1072
						2	109	2.29488	0.02174	0.601645
						Final	163	2.29588	0.021683	0.800153

DFS, disease-free survival.