Does chemo radiation kills the remaining cancerous cells of a t4 colon cancer ? surgery has been done and also how to know if there are stillcancercel

It should.: Chemo and radiation are supposed to do what surgery may not be able to, and that is kill the remaining cancer cells/tissue in the body. Taking levels of CEA (carcinoembryonic antigen) can be used to check for recurrence of the cancer. Radiologic exam, blood count, colonoscopy every 1 to 3 years, and liver tests can also be used to check for recurrence.

Maybe: The hope and rationale for chemo radiation is to kill the remaining cells. The only proof of efficacy is with followup imaging and tumor marker studies (cea).