CEACAM5 and colorectal carcinoma: CEA by itself is not highly sensitive or specific for CRC,30 but when measured serially in the setting of surveillance for recurrent CRC, it has been shown to detect recurrence several months before other modalities, including CT imaging alone.31,32,33 Although CEA has been shown to be potentially cost-effective,34 there remain no prospective data demonstrating that a clear survival benefit can be attributed to the addition of serial serum CEA measurements.