They were most likely referring to the level of CEA, a colorectal cancer tumor marker, in his blood. Unfortunately, a rising CEA level following treatment for colon cancer usually indicates a recurrence of the patient's cancer.
He should be seen by his Oncologist, and a search for the source of this rising CEA level. Hopefully, he can receive additional treatment.
Sincerely/ Robert A. Wascher, MD, FACS
www.doctorwascher.com
www.oncoguard.com