Carcinoembryonic antigen is the classical tumor marker for colorectal cancer. Its main clinical utility is in monitoring patients with colorectal cancer.
The plasma level of CA 242 is also elevated in patients with colorectal cancer.
In this study, investigators from Sweden assessed whether the plasma levels of these markers were elevated before clinical diagnosis of colorectal cancer.
The team identified 124 patients with colorectal cancer.
|Elevated level of CA 242 were not related to cancer risk.|
|Diseases of the Colon and Rectum|
For each case, 2 referents were randomly selected and matched for gender, age, date of sampling, and fasting time.
The team analyzed plasma from the included patients for carcinoembryonic antigen and CA 242.
The investigators found that an elevated level of carcinoembryonic antigen before diagnosis was associated with an increased risk of developing manifest colorectal cancer.
However, an elevated level of CA 242 was not related to cancer risk.
The elevated levels of carcinoembryonic antigen were found only in the 2-year period immediately before diagnosis.
In this group, 30% of all plasma samples from cases were carcinoembryonic antigen-positive and 71% were future Dukes A or B cases.
The investigators determined that the specificity of the carcinoembryonic antigen test for identifying future colorectal cancer patients was 0.99, with a sensitivity of 0.12.
For CA 242 the specificity was 0.92 and the sensitivity was 0.1.
Dr Richard Palmqvist's team concluded, "Elevated carcinoembryonic antigen levels strongly indicate occult colorectal cancer".
"Although the specificity of the carcinoembryonic antigen test in its present form is high, the sensitivity is disappointingly low, prohibiting the use of the carcinoembryonic antigen test for mass screening".