Table 3.

Trials for the treatment of advanced colorectal cancer. The surrogate endpoint indicates tumor response (or not) between 3 and 6 months. The true endpoint indicates with overall mortality (or not) by 12 years.²⁸ The estimated treatment effects are differences in fractions that account for censoring.¹⁵

Trial	Estimated effect of treatment on the surrogate endpoint	Estimated effect of treatment on the true endpoint	Average sample size per arm	Estimated sampling variance of the effect of treatment on the true endpoint
i	xi	yi	ni	wi
1	0.00264784	−0.00423654	158	0.00697091
2	0.00424809	0.0698386	162	0.00684591
3	0.00630874	0.0196868	356	0.00275263
4	0.0236874	0.0393162	180	0.00544156
5	0.0262514	−0.250522	26	0.034631
6	0.0393375	0.044984	46	0.020156
7	0.0491228	0.0555556	184	0.00503523
8	0.0607485	0.130383	306	0.0032042
9	0.0658915	−0.0989863	164	0.00604527
10	0.0792541	0.0839161	60	0.0170716
11	0.104938	0.116667	324	0.00304328
12	0.107668	0.0213607	180	0.0055205
13	0.109419	0.0510577	382	0.00308951
14	0.129886	0.0696033	148	0.00663814
15	0.131535	0.0311355	156	0.00625076
16	0.140312	0.13857	248	0.00295039
17	0.150871	0.139344	124	0.0076863
18	0.172547	−0.0864888	62	0.0162696
19	0.200272	−0.00567514	174	0.00577375
20	0.230317	0.233328	64	0.0132916
21	0.238828	0.10696	74	0.0133953
22	0.238828	0.10696	74	0.0133953
23	0.247371	0.22021	64	0.0144687
24	0.255682	0.171875	130	0.00723255
25	0.257433	0.0154741	80	0.0124803
26	0.261034	0.113493	16	0.0565146
27	0.313043	0.042029	52	0.0185411