Survival curves in colon patients according to four age subgroups.

<p>Group 1 vs. group 2, <i>χ2 = 0.893, P = 0.345</i>; group 1 vs. group 3, <i>χ2 = 7.539, P = 0.006</i>. gropu 1 vs. group 4, <i>χ2 = 9.937, P = 0.002</i>; group 2 vs. group 3, <i>χ2 = 4.685, P = 0.030</i>. <i>group 3</i> vs. group 4, <i>χ2 = 7.052, P = 0.008</i>; group 3 vs. group 4, <i>χ2 = 0.075, P = 0.785</i>.