Table 1.
R2 values for recurrence in the colorectal cancer data
| Study | R2 |
|---|---|
| C01 | 0.51 |
| C02 | 0.38 |
| C03 | 0.55 |
| C04 | 0.52 |
| C05 | 0.48 |
| C06 | 0.42 |
| C07 | 0.38 |
| INT-0035 | 0.52 |
| NCCTG 784852 | 0.57 |
| NCCTG 874651 | 0.54 |
| NCCTG 894651 | 0.56 |
| NCCTG 914653 | 0.53 |
Note: The method of Nagelkerke (1991) was used to calculate R2. In particular, two PH models were compared. Both had age (log-transformed), stage and treatment as covariates; one included recurrence as a time-dependent covariate, the other did not. The baseline hazard function was modelled using a Weibull distribution.