This topic has been discussed before but want to mention to ask your oncologist for a CTDNA test.... I think the test you refer to is CEA. Data published just recently shows that CEA is not useful at all to detect recurrence. CTDNA is recommended right after surgery and again 4 to 6 weeks after completion of chemo. Try to complete the full chemo regimen! It's tough! But it's getting rid of any residual cancer!