Tumor marker for colon and rectal cancer - types, preparation, meaning. Tumor markers for intestinal cancer: types and methods of detecting pathologies using these substances What tumor markers to test for intestinal cancer

The role of these antigens is great. With their help, it is possible to identify a tumor at an early stage, when there are no serious complications yet, and the patient’s life can be saved.

Kinds

There are two types of tumor markers:

• highly specific, with which you can detect a specific type of tumor;
• non-specific, which indicate the presence of cancer.

Diagnosis of intestinal cancer occurs when the following cancer markers are detected:

• CEA (carcinoembryonic antigen). Indicates a colon tumor. Thanks to it, it is possible to predict the growth of a tumor, determine the stage of oncology and evaluate the effectiveness of treatment, as well as identify the likelihood of relapse after complete recovery.
• CA 19-9. The amount of this antigen increases with cancer of the large intestine, rectum, gallbladder and ducts, and pancreas. Using CA 19-9 it is impossible to accurately determine the location of the tumor, so CEA and CA 242 are additionally analyzed.
• CA 242. One of the main antigens for diagnosis.
• CA 72-4. It is a tumor marker for gastrointestinal cancer. It is most often detected in the large intestine.
• Tu M2-RK. This is a highly specific marker that can be used to detect metabolic disorders in cancer cells. Tu M2-RK makes it possible to make a prognosis regarding metastasis and relapses.

What other markers are accepted? Additionally, an analysis is carried out for SCC antigen (for anal cancer), AFP (malignant oncology of the sigmoid colon), LASA-P (malignant neoplasms in the intestinal organs) and SF 125 (tumor of the sigmoid colon).

What is the need for analysis?

It is necessary to determine the level of tumor markers in the following cases:

• detection of a tumor in the intestine at an early stage;
• determination of tumor size;
• predicting tumor growth, the likelihood of metastases;
• determination of the type of oncology;
• identifying an organ’s predisposition to oncology, preventing gastric and intestinal tumors;
• assessment of the effectiveness of treatment, the likelihood of recurrence of the tumor;
• therapy control.

Advantages and disadvantages of the diagnostic method

The advantages of diagnosing the level of tumor markers for intestinal cancer are:

• The ability to detect cancer when there are no symptoms.
• Possibility to evaluate the effectiveness of therapy. The more effective the treatment, the less antigen in the patient’s blood. If the level of tumor markers has increased, then it is worth choosing a different treatment tactic.
• Possibility of preventing relapse. To do this, the test must be taken every 3 months after recovery.

The disadvantage of this diagnostic method is that some markers are nonspecific, and therefore may indicate cancer processes both in the intestine and in other organs.

Also, a slight increase in antigen levels does not always indicate cancer. This can happen even in healthy people, so sometimes it is not advisable to make a diagnosis based on tumor marker results.

High levels of antigens indicate late stage cancer.

Rules for taking the analysis

To identify tumor markers for colon cancer, you need to donate blood. Only Tu M2-RK is detected in feces.

When donating blood, you must follow these recommendations:

• the analysis is carried out on an empty stomach, blood is taken at least 8 hours after eating;
• On the eve of diagnosis, you should not drink tea or coffee with sugar, as well as juice, you can only drink water, you should avoid fried, fatty and smoked foods.

Blood is taken from a vein. The result can be obtained within 7 days, more often the analysis is ready within a day.

Feces must be obtained naturally, that is, without the use of an enema or laxatives.

Decoding the results

The decoding should be carried out by specialists from the laboratory in which the diagnosis was carried out. Laboratories may use different measurement scales.

Norm:

• REA – absent;
• CA 72-4 – no more than 6.3 IU/ml;
• CA 242 – no more than 30 IU/ml;
• SA 19-9 – no more than 40.

If the antigen concentration increases, this indicates oncology.

Errors

No tumor marker is 100% specific. The following factors may influence the increase in its level:

• pregnancy;
• liver diseases, for example;
• chronic pancreatitis, ;
• gastrointestinal infections;
• rheumatism;
• pneumonia, acute or chronic bronchitis;

Only a combination of antigens makes it possible to determine oncology.

This type of diagnosis is a salvation for cancer patients, as it gives a chance for timely treatment. You can get tested in any laboratory.

Useful video about tumor markers

is a serious disease, the treatment of which directly depends on how quickly it is detected. The earlier cancer is detected, the more effective its treatment will be. One of the ways to detect a disease in its initial stages is to detect tumor markers in the human body.

These compounds, which are of a protein nature, are contained in the biological fluids of an organ suffering from cancer. In order to detect them, as well as determine their indicator, urine, blood and, in rare cases, feces may be taken from the patient for testing.

Tumor marker is a modern diagnostic method

The statistics from the World Health Organization are quite depressing: the number of patients suffering from malignant tumors is growing from year to year. This growth is influenced by many harmful factors:

• bad habits
• poor environmental condition
• hereditary predisposition
• population aging
• radiation and others

In addition, the age of cancer is decreasing: oncology clinics are increasingly receiving patients who are not yet thirty years old. Often, the development of malignant formations in the human body is asymptomatic - in the early stages, an oncological disease does not have any obvious signs of development, and the patient does not even suspect its presence in his body.

Over time, a person may complain of constant fatigue, weight loss and lack of appetite, but these signs are perceived by many as harmless manifestations of other non-dangerous phenomena. And only when the disease develops so much that metastases appear - the spread of the tumor to nearby tissues, and the process is characterized by acute pain, the patient seeks help from doctors.

The problem is that in the later stages the pathology is much more difficult to treat, and in some cases the treatment does not bring results at all.

Modern methods for diagnosing cancer include various visual methods -, etc., as well as a method based on the detection of tumor markers in the patient’s blood or urine. Tumor markers are proteins that appear as a result of tumor development and an increase in the number of malignant cells. The structure of these proteins is diverse and among them they are divided into two main types:

1. tumor markers of high specificity, which can be detected in the event of the development of a certain type of malignancy
2. nonspecific markers, the detection of which indicates the development of cancer in general

Determining the number of tumor markers in human biological fluids is one of the modern methods for diagnosing oncological pathologies, which makes it possible to detect the disease at the initial stages of its development.

Main types of tumor markers for colon cancer

Various tumor markers are used to diagnose cancer cells.

Bowel cancer can be diagnosed by detecting the following tumor markers.

Carcinoembryonic antigen

A substance produced by the cells of the fetal gastrointestinal tract when it is in the womb. For obvious reasons, adults should not have it. The determination of this tumor marker can be used in the following cases:

• if necessary, find out the size, determine the stage of its development and predict its growth in the future
• if necessary, evaluate the effectiveness of treatment of adogenic cancer in patients, taking into account the previously determined indicator of carcinoembryonic antigen
• to conduct diagnostic monitoring of patients in order to determine possible re-development of the disease

CA 19-9

It is applied for:

• control of therapy for patients suffering from oncological pathologies of the following gastrointestinal tract organs - gallbladder and duct,
• for diagnosing colorectal cancer and malignant tumors of the rectum
• for monitoring the therapy of cancer patients and timely detection of relapses

This antigen can be found in epithelial cells of the pancreas, gastric mucosa, intestines and liver cells. A large amount of the substance is found in urine, gastric juice, bile, saliva, and seminal fluid. The marker does not allow one to accurately determine the location of tumor formation.

CA 242

In general, it can be detected in pathologies similar to the CA 19-9 antigen. The peculiarity of this tumor marker is that it is more specific and its detection makes it possible to identify possible cancer of the pancreas or rectum. The ability to detect cancer at the initial stages makes the marker the main way to diagnose malignant tumors of the gastrointestinal tract.

CA 72-4

Used to detect malignant tumors and colorectal cancer. In most cases, tests for this antigen are carried out in combination with tests to detect carcinoembryonic antigen. Its detection indicates cancer affecting the stomach and colon tissue.

Tu M2-PK

A tumor marker that can be used to detect changes in metabolic processes in malignant tumor cells. The protein is highly specific and is used to identify various neoplasms. Detection of the marker makes it possible to identify cancer tumors, their metastasis and relapses.

Various types of tumor markers are used to detect bowel cancer. Some of them make it possible to detect the presence of a malignant tumor in general, and some also make it possible to find out the approximate location of the pathology.

Blood test for cancer markers

Tumor markers for colon cancer give reliable results

Detection of tumor markers in the blood makes it possible to simply and effectively diagnose cancer in a patient. From a certain age, such studies are recommended for preventive purposes in order to prevent the possible occurrence of cancer pathology and its development to late stages.

The following reasons for conducting the study can be identified:

1. to obtain the necessary information about the development of the tumor, if any, thereby confirming or refuting the results of other diagnostic methods
2. to determine the nature of the tumor (benign or malignant)
3. the level of antigens before treatment, as well as its determination during therapy, makes it possible to evaluate
4. the effectiveness of the treatment, which, if necessary, makes it possible to make some adjustments to it
5. monitoring the patient’s condition after completion of therapy and early detection of relapses

Despite the fact that tumor markers are used to detect pathologies, or to confirm the absence of such, they can also be detected in a healthy person. This is due to the fact that the levels of tumor markers in a person’s blood can also increase with the formation of various cysts, benign formations, in the presence of infection, or various types of cancer.

In some cases, even a simple cold causes an increase in the levels of certain tumor markers in the patient’s blood.

Obtaining material for analysis is done by taking blood from a vein. To do this, it is necessary that the patient does not eat food eight hours before the test. For patients who have undergone treatment, it is advisable to conduct a similar blood test every three to four months. The analysis result can be received as early as the next day.

Depending on where the cancer is located, different antigens can signal its development. During the blood test, the type of tumor markers and their quantity are determined. If the established standards are significantly exceeded, the patient may be prescribed additional tests to confirm the diagnosis. If it is confirmed, measures will be taken to treat the disease.

A blood test for tumor markers is carried out to detect specific protein substances in the patient’s blood that are produced by cancer cells. Identification of tumor markers does not always indicate the presence of cancer.

A tumor marker is a specific protein that makes it possible to diagnose cancer at all stages of its development. Some tumor markers can indicate a specific location of the malignant tumor, while others simply indicate its presence. Today, tumor marker tests are one of the most effective cancer tests.

What are tumor markers, and how do they help identify a malignant tumor? The answer is in the video:

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Rectal cancer is a dangerous disease that is becoming increasingly common in modern society. The number of people facing this problem is increasing every year, which is associated with environmental factors, unhealthy lifestyle, unbalanced diet and other external influences on the human body. At the initial stage of development, the disease is practically asymptomatic, leading to the unhindered growth of a cancerous tumor in the intestinal cavity and the spread of cancer cells throughout the body. Therefore, early detection of cancer is a priority task of modern science and medicine.

Biochemical analysis

Today, it is possible to detect cancer, including rectal cancer, at the very beginning of its development, when characteristic symptoms have not yet appeared, or the symptoms are not clearly expressed. To do this, during early diagnosis, a biochemical analysis is done for tumor markers, which can be detected in the biological fluids of a cancer patient.

A tumor marker is a substance (most often a protein) that enters the patient’s blood or urine as a result of the vital activity of cells of a malignant tumor or the tissue surrounding it. Tumor markers discovered as a result of the analysis give reason to suspect that a person has a malignant neoplasm.

It is customary to distinguish two types of tumor markers:

1. Highly specific. The detection of such substances indicates the presence of a certain type of malignant neoplasm.
2. Non-specific. Exceeding their norm may indicate the development of an unspecified type of cancer.

Highly specific markers include the CEA (carcinoembryonic antigen) indicator. This is a fairly sensitive marker of rectal cancer. The production of carcinoembryonic antigen is characteristic of cells of the gastrointestinal tract of the developing embryo. This marker, detected in a person in adulthood, gives reason to suspect the presence of a malignant neoplasm in the rectum.

However, even a highly specific marker cannot be the basis for definitive conclusions regarding the presence of cancer. Indicators may deviate from the norm for other reasons unrelated to oncology. That is why, in order to make an accurate diagnosis, it is necessary to conduct a comprehensive examination of the patient using additional research methods.

Why the analysis is carried out and how to prepare for it

Biochemical analysis is carried out both for diagnostic purposes and to monitor the effectiveness of antitumor treatment. Testing for tumor markers is prescribed in the following cases:

• for early detection of the presence of cancer processes;
• to diagnose the size of the tumor and the degree of its development;
• to determine the effectiveness of treatment. If the indicators do not decrease, the therapy does not produce positive results;
• to identify possible relapses in the early stages.

The test often uses blood samples from the patient and, in some cases, stool samples, which is common in colorectal cancer tests. The effectiveness of further therapy depends on the reliability of the results of the study of the patient’s biological material.

To get the most reliable research results, you should prepare for a blood test. The collection must be done on an empty stomach. You can eat no later than 8 hours before the procedure. It is recommended to drink only clean water; sugar-containing drinks are prohibited. You should also pay attention to the fact that you are taking medications, which can lead to distortion of the study results. Ideally, blood should be donated before starting treatment. A few days before the analysis, it is recommended to adhere to a certain diet that limits the consumption of fats, fried foods and alcohol. Smoking may also affect test results.

If a malignant tumor of the rectum is suspected, a stool test for occult blood and the presence of tumor markers is prescribed. The use of any laxatives or enemas is not recommended before collecting a stool sample. Biological material must be collected naturally. This happens during bowel movements. It is important to prevent urine from getting into the stool.

Interpretation of results

For patients with rectal cancer, determining the dynamics of disease development and the effectiveness of therapy depends on the level of CEA concentration in the blood. An increase in antigen levels indicates that the disease is progressing. If this marker tends to decrease, the therapy has a positive effect. The CEA tumor marker makes it possible to detect relapse of the disease after completing a course of treatment. Already in the initial stages of cancer, when the first symptoms are absent, the concentration of antigen in the blood increases significantly. With the development of a malignant tumor of the rectum, the symptoms intensify, and the CEA marker continues to increase.

This marker may indicate not only rectal cancer, but also the presence of other cancers. It is used as a marker to detect oncology of the gastrointestinal tract, as well as lung cancer. An increase in antigen levels can also be caused by autoimmune or chronic diseases, as well as bad habits (smoking). Therefore, if symptoms characteristic of a cancerous tumor do not appear, a definitive diagnosis is not recommended.

Education: Graduated from the Russian National Research Medical University. N.I. Pirogov, Faculty of Medicine. Took advanced training courses. Primary specialization is in coloproctology at the State Research Center of Coloproctology. Worked at the City Scientific and Practical Center for Coloproctology of St. Petersburg.

Experience: Proctologist. Medical practice experience – 25 years. Author of more than 40 articles on medical topics. A regular participant in conferences and symposia, where problems of modern medicine are covered.

Provides highly qualified diagnosis and treatment of many diseases: hemorrhoids, anal fissures, various diseases of the colon, and successfully diagnoses neoplasms of the perianal area and rectum in the early stages. Also conducts examinations of children.

According to WHO data, every year about 10 million patients around the world are diagnosed with cancer, and tumors of the gastrointestinal tract occupy 3rd place in this “rating”. This disease is one of the main causes of death for almost 8 million patients every year. Agree, the statistics are terrifying.

That is why it is so important to identify a tumor as early as possible, when there is not even a “small sign syndrome”, which includes sudden weight loss, lack of appetite and unexplained fatigue. After all, patients often classify these symptoms as seasonal vitamin deficiency, stress, or a common cold. A trip to the doctor is usually marked by the appearance of acute pain, which means only one thing - the cancerous tumor has matured and metastasized to nearby organs, and therefore it is not only very difficult to fight cancer pathology, but sometimes it is impossible.

Today, diagnostic measures for neoplasms in the early asymptomatic stages include, in addition to imaging examinations (various types of endoscopy, ultrasound, etc.), also the determination of tumor markers in biological fluids.
Tumor markers are specific proteins that are produced by tumor cells or normal cells surrounding the tumor, to a level significantly exceeding normal values ​​and detected in the biological fluids of the affected organ. That is, the patient’s blood, urine, and very rarely the patient’s feces are used as material for their detection.

There are 2 types of tumor markers:

• highly specific, the detection of which indicates the development of a specific type of tumor;
• nonspecific, indicating the presence of cancer pathology in general.

Tumor markers for intestinal diseases

In intestinal cancer, special attention is paid to the detection of the following markers: CEA, CA 19-9, CA 242, CA 72-4, Tu M2-RK.

Carcinoembryonic antigen, or CEA

This tumor marker is produced by cells of the fetal gastrointestinal tract during pregnancy. Therefore, adults should not have it. Normally, its concentration does not exceed 0-5 ng/ml.

Indications for biochemical analysis are:
Predicting tumor growth, as well as obtaining additional information to accurately determine the stage of its development, since the CEA value before appropriate treatment indicates the size of the tumor.

Assessing the effectiveness of prescribed therapy in patients with adenogenic cancer (primarily the gastrointestinal tract, breast and lungs) taking into account the initial overestimated CEA value.

Monitoring patients to preclinically determine the development of relapse.

Carbohydrate antigen CA 19-9

Pathological is a value of 40 IU/ml. The marker is used for:

• monitoring the treatment of cancer patients with pathologies of the esophagus, pancreas, colon, gallbladder and duct,
• colorectal cancer, rectal cancer, and ovarian tumors;
• monitoring of cancer patients for early diagnosis of relapses.

The antigen can be found in epithelial cells of the pancreas, gastric mucosa, liver cells, bile, in the small and large intestines. Its concentration is high in saliva, urine, seminal fluid, gastric juice, secretions of the duodenum, bile and pancreas. Because of this, the organ specificity of this test is quite low, and therefore it is impossible to determine the exact location of the tumor based on its results.

Onomarker CA 242

It is detected in the same pathologies as CA 19-9, but is more specific. Therefore, its detection often indicates the development of oncopathology of the pancreas, rectum and large intestine at the earliest stages.
The tumor marker is one of the main ones in the diagnosis of gastrointestinal tumors, since its results make it possible to predict a new relapse within 3-5 months. Normally, its value does not exceed 0 to 30 IU/ml.

Tumor marker CA 72-4

The normal value does not exceed 6.3 IU/ml.
The antigen is used to diagnose gastric and colorectal cancer. As a rule, it is carried out in conjunction with a laboratory test to determine CEA. It has been identified in tissues from colon tumors, non-small cell lung cancer, and gastric cancer. In a healthy person, the antigen practically does not occur.

Tumor marker Tu M2-PK (tumor pyruvate kinase type M2)

This is a metabolic tumor marker that reflects changes in metabolic processes in cancer cells. Tumor M2-PC is a fairly highly specific cancer protein, which does not have any particular organ specificity and is considered a kind of “marker of choice” for diagnosing a variety of neoplasms. Determining its content allows early diagnosis of tumor development, metastasis or relapse.

Preparing for diagnosis: how and where to take tumor markers

The biological material for the detection of CEA, CA 19-9, CA 242, CA 72-4 is blood.
It is recommended to donate blood in the morning on an empty stomach. Therefore, blood collection should be carried out at least 8 hours after the last meal. But it is better if this period is 12 hours. In addition, it should be noted that it is strictly forbidden to drink juice, tea and coffee with sugar on the eve of the diagnosis; you should drink plain water.

Determination of tumor markers CEA, CA 19-9 and CA 242 is carried out within 1 day.
When donating blood to detect CA 72-4, in addition to the above recommendations, you should also pay attention to taking biotin. So, if the dose of the drug exceeds 5 mg/day, blood for analysis cannot be taken for at least 8 hours after the last dose of biotin.

The analysis is carried out over 3-7 days.

The biological material for detecting Tu M2-RK is feces. Stool should be obtained for diagnosis only naturally, without the use of enemas or laxatives. 2 tsp are placed in a special container. stool and sent to the laboratory. The result will be ready in 7 days.

What tumor markers can show

It must be taken into account that no single marker exhibits 100% specificity, and therefore a combination of them is used for more accurate diagnosis. Eg,
stomach tumor – antigen CA 242 and CEA;
rectal cancer - CEA, antigens CA 19-9 and more specific CA 242;
colon cancer – CEA, antigens CA 19-9 and CA 242, detection of tumor pyruvate kinase (Tu M2-PK).
However, an increased value of tumor markers does not always indicate the development of cancer. Thus, an increase in CEA may indicate liver pathologies, such as cirrhosis, the development of Crohn's disease, acute or chronic pancreatitis, CA 19-9 antigen - cholecesstasis and/or cholecystitis, CA 72-4 antigen - cirrhosis of the liver, gastric ulcer, pneumonia, acute or chronic form of bronchitis, Tu M2-RK - bacterial infections of the gastrointestinal tract, rheumatism and/or diabetic nephropathy. In view of this, all biochemical analyzes must be supported by clinical studies.

Principle of CEA monitoring for colon and rectal cancer:
The role of CEA monitoring in patient management (CRC) is still controversial. The sensitivity and specificity of CEA are not sufficient to consider it as a tool for primary screening of cancer at an early stage. In addition, various diseases can cause an increase in CEA levels.
The use of CEA as a marker of CRC is most indicated in two cases: 1) monitoring patients who have undergone surgery but remain candidates for further treatment and 2) assessing the response to treatment in patients with metastases. The decision-making process must be comprehensive, i.e. be based not only on the level of CEA, but also on the results of clinical examination, endoscopy and instrumental research data.

A) Methods for monitoring tumor marker CEA:
CEA level in plasma: immunological test.
Pathological specimen: immunohistochemical study and PCR analysis => tumor is almost always positive for CEA, even if its plasma level is normal; search for micrometastases?
CEA scintigraphy: previously used to search for metastases and relapse, in the era of PET it has lost its significance.

b) Sum of evidence for the effectiveness of CEA tumor marker control:
Rectal cancer is less CEA positive/secreting than colon cancer.
Half-life of CEA from plasma: 4-8 days.
Other reasons for increased CEA (> 20%):
- Cancer of other organs: cancer of the pancreas, stomach, lung, breast.
- Non-oncological causes: IBD, benign polyps, liver cirrhosis, hepatitis, chronic lung diseases, pancreatitis, smoking.
Value of REA measurement:
- Before treatment: minimal/not significant for screening, diagnosis, evaluation.
- Postoperative: important during observation.
- Metastasis: important for monitoring response to treatment and assessing disease progression/regression.

V) Alternative:
Other observation methods: medical history and physical examination, colonoscopy, CT, PET.

G) The importance of CEA in colon and rectal cancer:

I. Screening. Does not live up to expectations: lack of sensitivity and specificity with more than 20% false-positive increases in CEA levels, for example, in smokers and in some benign diseases.
Indications. Determination of CEA is not indicated as a screening test.
"Underwater rocks". False reassurance; the CEA level does not confirm or replace data obtained from other screening methods (for example, colonoscopy).
Data. Increased CEA levels: stage I (< 5%), стадия II (< 25%).

II. Symptom assessment
When assessing specific symptoms (such as bleeding, palpable tumor), the role of CEA in confirming/excluding the diagnosis and assessing the effectiveness of treatment is limited: insufficient specificity, since an increase in CEA levels occurs in various conditions; but a CEA level > 10-15 is most likely not associated with a benign disease, and a CEA level >
Indications. Determination of CEA levels is not indicated as a diagnostic method; definitive pathological examination and radioimaging methods have an undeniable advantage.
"Underwater rocks". If the result is negative, a malignant tumor cannot be excluded.

III. Before treatment (before surgery and chemoradiotherapy)
The significance of CEA before surgery is limited: these data are less significant than the pathological stage of the tumor, the level of CEA never affects the treatment plan, and the prognostic value is low.
Indications:
As an initial parameter: normalization of the level is expected in the postoperative period (after 4-6 weeks or more), a constant level is suspicious in relation to undetected lesions.
Prognostic parameter: CEA level< 5 связан с лучшим прогнозом при раке толстой, но не прямой кишки? Уровень РЭА >10-15 is most likely not associated with a benign disease, and a CEA level > 20 is highly suspicious for metastases.
"Underwater rocks". CEA expression/secretion: Rectal cancer causes a smaller increase in CEA levels than colon cancer.

IV. Observation after radical treatment. Normalization of the CEA level, which was elevated in the preoperative period after radical surgery, occurs within 4-6 weeks => early detection of relapse or metachronous cancer increases the chances of successful intervention.
Indications. After radical resection for colorectal cancer (CRC) in stages I-III in patients who can undergo re-intervention (regardless of the preoperative level of CEA):
Normal level before and after resection: determined every subsequent 2-3 months for two years or more.
Increased level before, normal after resection: determined every subsequent 2-3 months for two years or more.
Persistent enhancement after resection: search for metastases or monitor response to treatment.
Normal level after resection, increasing during follow-up: search for tumor recurrence/metastasis.
"Underwater rocks". CEA is not a predictor of resectability of relapse. A transient increase in CEA levels is caused by liver dysfunction and/or chemotherapy.
Data. CEA and persistent disease or relapse: sensitivity is 50-80%, specificity is 90%. CEA levels are elevated in >80% of relapses. In 50-65% of patients with cancer recurrence, CEA levels increase before or with the onset of clinical symptoms. Resectable relapses: 20% are diagnosed by CEA, the rest by symptoms or other surveillance methods.

V. Evaluation of the effectiveness of treatment of relapses/metastases. CEA is a significant marker of tumor response to cancer-specific treatment (chemotherapy, radiation therapy, surgery) in patients with cancer relapse/metastasis. A mandatory addition to radiation diagnostic methods (CT, PET).
Indications. Patients with recurrent/metastatic cancer receiving cancer-specific treatment.
"Underwater rocks". Tumor progression according to radiological diagnostic methods and clinical signs without a concomitant increase in CEA. There is no correlation between the dynamics of CEA and survival.
Data. In one third of cases of disease progression (according to radiological diagnostic methods), there is no parallel increase in CEA levels. The level of CEA increases with metastases: in the liver up to 80%, in other organs - in 40-50% of cases.

Video tumor markers in normal conditions and in cancer