NRG-GI008 Colon Cancer

We are doing this study to find out if a blood test for circulating tumor DNA (ctDNA) can provide information that might help doctors figure out the most appropriate therapy for patients with colon cancer after they have surgery.

Colon Cancer

Adults ages 18+ who:

• Are diagnosed with Stage II or III adenocarcinoma of the colon
• Have had their tumor removed by surgery fewer than 60 days before joining the study

For more information about who can join this study, please contact the study team at nick.jeffries@duke.edu.

If you choose to join this study, we will test your blood for ctDNA, even if you've already had a previous Signatera test to check for the presence of ctDNA.

If your ctDNA test is positive, you will begin taking a standard chemotherapy regimen.

If your ctDNA test is negative, you will get a random assignment (like a coin flip) to 1 of 2 groups:

• One group will not start a chemotherapy regimen and will have their ctDNA routinely checked (the first test will be 3 months after joining the study, and then every 6 months for 4.5 years)
• The other group will start a standard chemotherapy regimen

If you are assigned to the group that receives ctDNA monitoring but not chemotherapy, you will be started on a standard chemotherapy regimen if you ever have a positive ctDNA test during your monitoring period.