Table 1.

Trials for the treatment of early colorectal cancer. The surrogate endpoint indicates cancer recurrence (or not) before 3 years, and true endpoint indicates overall mortality (or not) before 5 years.²⁶ 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	0.0133209	0.00810028	2136	0.000327462
2	0.0154465	0.0227297	878	0.000946246
3	0.031803	0.0625501	896	0.00084016
4	0.0370214	0.0370513	1390	0.000564888
5	0.0507431	0.0359503	724	0.00128489
6	0.0560784	0.0560784	408	0.00234467
7	0.0741955	0.0932471	1042	0.000764536
8	0.0756713	0.102222	456	0.00198833
9	0.109814	0.0733984	926	0.000967199
10	0.121802	0.0890725	248	0.00385288