Detailed interpretation of CEA rise, beginners to see this!

CEA is one
of the tumor markers that clinicians are familiar with.

1.

2.

3.

4.

This article attempts to answer these questions
.

1.

Carcinoembryonic antigen (CEA) is a tumor marker whose use is to screen malignancy in healthy people and to assist in the evaluation of disease
in patients with malignancies.

As an intercellular adhesion molecule, it promotes the binding of normal cells to tumor cells and plays an important role
in the metastasis of tumors.

Because CEA is metabolized through the gastrointestinal tract, CEA in the tumor state enters the bloodstream and lymphatic fluid circulation, causing abnormally elevated
serum CEA.

2.

CEA is known to have extremely low serum levels (<5ug/L)
in normal humans.

In patients with tumors, in addition to blood, CEA can be detected in gastric juice (stomach cancer), saliva (oral cancer, nasopharyngeal cancer), as well as chest and ascites (lung cancer, liver cancer), urine (urinary tract cancer), and the positive rate is higher because CEA in them precedes
the presence in the blood.

Note: CEA content is related to factors such as tumor size and whether there is metastasis, and the increase in CEA is particularly pronounced when liver metastasis
occurs.

Third, what is the significance of CEA increase?

CEA is mainly used to guide the treatment and follow-up of tumors, and the continuous observation of CEA concentrations in the blood or other body fluids of tumor patients can provide an important basis
for judging the condition, prognosis and efficacy.

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2.
Judge the efficacy after treatment:

Note: The efficacy of radiation therapy and chemotherapy is not necessarily proportional to
the volume of the tumor.

3.
Monitor tumor recurrence and metastasis: common protocol: 1 time after 6 weeks after surgery; 1 time per month within 3 years after surgery; 3-5 years every 3 months; 5-7 years every six months; Once every year after 7 years
.
If elevated is found, it is measured again after 2 weeks, and if it rises twice higher, it indicates recurrence or metastasis
.

Note: CEA plasma half-life is 1 to 7 days
.
Because CEA is primarily cleared by the liver (Kupfer cells and hepatocytes), cholestasis or hepatocyte disorders can prolong the half-life of CEA, leading to an increase
in the false-positive rate of CEA.

What is the significance of CEA testing in different populations?

The figure above shows the Log10P values
of CEA for 42 different diseases compared to the serum CEA control in healthy people.
Blue is used when serum CEA levels are lower than in the healthy control group, and red is used when the serum CEA level is higher than in the healthy control group[1].

1.
The significance of CEA in healthy people

Read the above chart will know that CEA elevation can occur in normal people, it is not unique to colorectal cancer, and many benign diseases can also lead to elevation
of CEA.
If a mild elevation of CEA is found on physical examination, it is likely to be inflammatory or benign, but there is a risk of more than 5 ng/ml and must be monitored
every 2 to 3 months.
If the review value gets higher and higher after a period of time, further testing
is required.

2.
The significance of CEA in the population of tumor patients

In many postoperative tumor patients, such as colorectal cancer, stomach cancer, etc.
, CEA is regularly reviewed every 3 to 6 months to monitor whether the metastasis is recurred
.
However, postoperative CEA rise is not necessarily the tumor recurrence progression, these malignant tumors include two parts, in addition to the metastatic recurrence of the original cancer, there may be a new second tumor, such as the combination of
other cancers, this probability is small but also possible, this time also needs to do further examination.

Reference: 1.
Hao C, Zhang G, Zhang L: Serum CEA levels in 49 different types of cancer and noncancer diseases.
Prog Mol Biol Transl Sci 2019, 162:213-227.