CEA Tumor Marker Test Range?
Hi.
Someone I know is going through cancer treatment (colorectal). His CEA score started at 12, went down to 6.5, and is now up to 25. Other than it going in the wrong direction, what do scores really mean? What is the possible range on the CEA tumor marker scale? Does it go up to 100, 1000, forever? Is there any correlation between # and prognosis or is it just that if it goes up, it’s not good?
Thanks!
The tumor has not been removed, he’s unable to have additional CT scans due to an allergic reaction to the chemicals used for that process, and he is presently doing chemo only (no radiation therapy yet).
Tagged with: allergic reaction • cancer treatment • cea tumor marker • chemicals • colorectal • correlation • marker • prognosis • radiation therapy • score • wrong direction
Filed under: Colorectal Cancer
Denisedds (88)
Firstly, CEA, is a tumor marker test that falls under the catagory of immunoassay testing. Each manufacturer of the instruments to perform this test develop their own method for the testing. Immunoassay instruments often do not correlate from one method to another (what may be 45 on one instrument and method, might be 55 on another instrument/method). It is important that people who are having serial tumor marker testing performed, have it done at the same place for the duration of the monitoring period to insure the most consistant results.
There are two ranges that are determined in any Laboratory test. The analytical range (AMR) and the clinically reportable range (CRR). The AMR, is the span of both minimum and maximum range that the instrument performing the test can analyze. The CRR is the maximum value that the laboratory determines to be clinically significant to patient diagnosis, beyond which obtaining a "number" is no longer useful. In the case of CEA, for example, lets say the instrument can measure CEA as low as 0.1 and as high as 100. Once the test exceeds the value of 100, the patient’s specimen must then be diluted to obtain the result. The laboratory will continue to dilute the specimen until they reach the maximum value that is clinically useful for diagnosis. This value varies from Laboratory to Laboratory, and test to test, and is determined by the Laboratory’s Medical Director. So, in one laboratory, they may be willing to dilute the specimen until they eventually report ">500" and at another laboratory they may continue to dilute the specimen until it is ">5000". At some point, obtaining the "number" becomes irrelavent, because it will not change the physician’s course of treatment nor will it further the physician’s diagnosis.
There can be some correlation between tumor marker values and treatment, but what the immediate course of action, after a single increase would be, is up to the physician monitoring the patient.
usually 5-10 is the normal range depending on the laboratories
just some caveats;
1. tumor markers are only numbers and nothing is absolute
2. some chemotherapy can increase cea like oxaliplatin based regimen
3. smokers and benign disease can have some increase in value
4. most labs will cap CEA at around 3-10,000
5. however CEA that continue to rise is a sign that patient has progressive cancer and would warrant imaging studies like CT-scan or PET scan
Usually, the CEA (carcinoembryonic antigen) is not used to test for cancer. The CEA number is used as a guage for later….. Using the Bayer ICMA methodology, non smokers should not be above 2.5, and smokers not above 5.0.
I’m guessing that your friend was originally tested at 12, had the colon cancer removed surgically, then was retested at 6.5. Typically, the CEA number will actually go UP after the first few treatments of chemo. Don’t fret.
After several treatments, and being diagnosed as cancer free, the CEA levels will be retested at intervals in order to help detect recurring colon cancer. An elevated CEA then, would INDICATE, not PROVE, the return of the cancer.