CEA

Japanese: CEA

Reference value

2.5ng/ml or less (RIA method)

Or 5ng/ml or less (EIA method)

High levels in colon and pancreatic cancer

CEA is a hormone that stimulates the large intestine and Pancreas water Viscera, gall bladder Tannou It is one of the glycoproteins produced by cancers that develop in the digestive system, such as those of the stomach and liver, and is measured when investigating these cancers.

Small amounts of CEA are produced in normal cells, but when cells become cancerous, large amounts appear in the blood, and when the level is more than twice the normal level, it is suspected that there is cancer somewhere.

In addition to the digestive system, high levels are also seen in cancers of the uterus, ovaries, and lungs.

To screen for colorectal cancer, whose initial symptoms are bloody stools or abnormal bowel movements, a fecal occult blood test (see reference) is performed, but recently CEA measurement has also become more common.

Also important for determining postoperative progress and recurrence

CEA levels decrease when cancer is removed or when the cancer shrinks due to chemotherapy.

A re-elevation of CEA during follow-up is important as an indicator of cancer recurrence or metastasis to other organs, so it should be measured once every 2-3 months. If a re-elevation is observed, immediate detailed examination such as abdominal ultrasound (see → reference) or abdominal CT (see → reference) is required.

Measures based on test results

The standard value for CEA varies by facility, with either 2.5 ng/ml or 5 ng/ml being used.

If the CEA level is high, there is a high possibility that there is cancer somewhere in the body, so depending on the symptoms, other blood tests, X-rays, ultrasound, CT scans, etc., mainly of the digestive system, as well as detailed examinations of the lungs and gynecology may be necessary.

In addition, because cancer is progressive and high CEA levels are caused by cancer, they tend to rise, so a repeat test will be performed in 1-2 months. If there is no change, there may be no need to worry about the high levels.

Although CEA levels are high in smokers, they do not often exceed twice the normal level. If a person smokes and their CEA level is slightly higher than the normal level, it is difficult to interpret.

The main diseases suspected are

◆ High levels → Cancer: colon, pancreas, gallbladder, lungs, uterus, ovaries, liver, stomach, etc.

Others: diabetes, elderly, smoking

The general term used by doctors is "CEA," which stands for carcinoembryonic antigen.

Source: Hoken "4th Edition: A book that explains the tests you will receive at the hospital" Information about the 4th Edition: A book that explains the tests you will receive at the hospital

Japanese:

基準値

2.5ng/mℓ以下（RIA法）

もしくは5ng/mℓ以下（EIA法）

大腸・膵臓がんなどで高値に

　CEAは、大腸や膵すい臓、胆嚢たんのう、胃、肝臓など消化器系にできるがんがつくり出す糖蛋白のひとつで、これらのがんを調べるときに測定します。

　CEAは、正常細胞でも少量つくられていますが、細胞ががん化すると血液中に多量に出現し、基準値の2倍以上になると、どこかにがんのあることが推測されます。

　消化器系以外では、子宮や卵巣、肺のがんでも高値を示します。

　血便や便通異常を初発症状とする大腸がんのスクリーニングには、便潜血反応（→参照）が行われていますが、最近ではCEAを測定することも多くなりました。

術後の経過、再発の判定にも重要

　CEAは、がんを切除したり、抗がん剤療法でがんが縮小したりすると値が低下します。

　その後の経過観察でのCEAの再上昇は、がんの再発やほかの臓器への転移などを疑わせる指標のひとつとして重要になるため、2～3カ月に1回は測定します。もし、再上昇を認めた場合は、ただちに腹部超音波（→参照）や腹部CT（→参照）などの精密検査が必要です。