IN last years Among specialists in the treatment of cancer, a diagnostic method based on intestinal tumor markers has become widespread. Colon cancer, according to statistics, is one of the most common types of cancer among the population. In the treatment of this disease, like any other cancer pathology, early detection of a tumor is extremely important, and for this, specialists analyze patient samples for specific proteins and antigens. Tumor markers are special substances that are produced by tumors during their development. Markers are observed in urine and blood tests, and indicate the expansion of the pathological process and an increase in the number of degenerated tissue cells. What can tumor markers be, and why can they help detect cancer?
What are tumor markers?
Cancer of the gastrointestinal tract today, alas, is very common. The reason for this is poor ecology, hereditary problems, hobby bad habits, Unhealthy Lifestyle, chronic diseases, exposure to various radiations surrounding modern man, and other factors. Cancer tends to “grow younger”, affecting people even before the age of 30.
On initial stages the disease does not manifest itself in almost any way, patients do not experience negative symptoms. And when they appear, and people finally turn to a specialist, the disease has already seriously affected the body. General analysis blood for intestinal cancer is not always able to detect the cancer process, and doctors long years We were looking for a way to detect cancer at its inception. As a result of these searches appeared new technique– diagnosis using tumor markers.
Tumor markers for intestinal cancer have a significant advantage - the possibility of early detection of the disease, much earlier than classical diagnostic methods can do. Thanks to this, the patient can begin therapy much earlier - which is extremely important in such a dangerous and insidious disease like cancer.
A blood test for oncology usually detects two types of markers:
- highly specific - indicating a specific type of pathogenic cells;
- general, accompanying the most different types cancer.
Markers of intestinal cancer pathology allow specialists to solve a number of problems:
- Determine the location of the tumor.
- Monitor the patient's condition over time during treatment, monitor his condition after removal of the affected tissue.
- Prevent relapse of the disease.
- Identify people at risk for intestinal and gastrointestinal diseases in general.
The following main tumor markers for rectal cancer are used in diagnosis today:
- alpha-fetoprotein test. An increase in its concentration shows that there is a neoplasm in the sigmoid part of the intestine, and the concentration itself demonstrates the stage of the disease;
- CA 72-4 and often accompanying LASA-P are markers indicating problems with the gastrointestinal tract;
- CA 242 - it is considered basic for the diagnosis of various intestinal tumors;
- test for carcinoembryonic antigen - more often called CEA. It is very sensitive to the occurrence of pathological formations in the colon;
- test for the marker CA 19-9 - another protein, the presence of which in the blood is characterized by colon cancer, as well as rectal cancer. As a rule, it complements CEA and the marker CA 242;
- protein CA 125 - this tumor marker for cancer warns of disease of the sigmoid intestine;
- The SCC antigen tells the doctor about a tumor near the anus;
- pathological intestinal neoplasms also lead to an increase in the level of CYFRA 21-1 protein.
Timely initiation of therapy can significantly improve the prognosis of the disease, or even lead to complete victory over colon cancer.
Meaning of markers
When making a diagnosis using markers, the doctor must remember that, unfortunately, none of them can be considered 100% specific for a particular type of cancer. Also, an increase in the concentration of one or more tumor markers may not always indicate the onset of pathological processes cancerous in the body. Sometimes even in completely healthy patients the concentration of these substances increases slightly. It is for this purpose that standards for marker levels in the blood were introduced.
And if the readings begin to exceed everything acceptable standards- this already speaks of active development malignant tumor, against the background of this process, the level of markers is always growing.
It should also be borne in mind that even if blood tests reveal an increase in the level of some specific marker, this does not necessarily indicate a specific location of the tumor: the tumor may be in a different place than expected. Taking into account all these nuances, doctors advise using not only a test for tumor markers when examining for intestinal cancer, but also alternative methods that check the result obtained. Thus, the analysis under consideration is a method indicated for use in combination with other examination techniques.
But, even despite the need for such testing, diagnosis using tumor markers is indispensable in cancer therapy. For example, if the concentration of a substance, according to the results of the analysis, decreases, the doctor can conclude that the treatment is effective, and its increase, on the contrary, serves as a signal to change the treatment strategy.
Not only patients or persons suspected of having rectal cancer are examined for oncology, but also those groups of citizens who are at risk of cancer. They are tested four times a year, quarterly, and the decision to take a sample is made by the treating specialist.
How the sample is taken
As follows from the above, blood tests for tumor markers are performed in combination with other diagnostic techniques. The advantage of markers is their ability to show the location of the tumor, even if the latter is not visible on x-rays or during endoscopy.
If a patient is suspected of having an intestinal tumor, a blood sample is taken. It is taken on an empty stomach, early in the morning. Last appointment There should be food no later than 8 hours before the blood is taken, but doctors recommend eating at least 12 hours before.
In addition to restrictions on food, there are also restrictions on drinking; the patient should refuse:
- tea, especially strong;
- coffee with added sugar;
- juices
Only plain water is allowed to drink. IN mandatory This test is performed by patients who have already been diagnosed with cancer of the intestine (and other organs). Based on the diagnostic results, the doctor evaluates the effect of treatment and the dynamics of his patient’s condition, carrying out this procedure at intervals of 2 to 4 months.
Laboratory assistant carries out sampling venous blood. After this, the sample is sent to the laboratory, and the result will be ready in about a day. Having deciphered the readings of tumor markers, the doctor determines their types and concentration levels, on the basis of which a conclusion is made which parts of the intestine are affected by cancer, and what is the progress of the disease.
For example, the CA 242 marker normally has a concentration of 0 to 30 IU/milliliter. If its levels are too high, a significant concentration indicates an active course of intestinal cancer (although a connection with pancreatic disease is possible). The specified marker shows high values already in the first stages of the tumor.
Another significant protein is CA 19-9. It is found in blood and other biological fluids: urine, seminal fluid, gastric juice and saliva.
The marker CA 72-4 is more accurate; it is specific for oncology of the lungs, stomach and colon. You should always remember that diagnosing intestinal tumors using tumor markers for cancer is not independent method diagnosis, and should be used in combination with other techniques.
Tumor markers- these are substances that are produced by neoplasm cells or nearby cells. To diagnose and monitor the effectiveness of treatment of malignant intestinal tumors, immunological study to identify tumor markers. Their concentration is influenced by the aggressiveness of tumor growth and the extent of the process, which makes it possible to suspect cancer and evaluate the effectiveness of therapy, and determine the degree of radical intervention.
Over 200 tumor markers have been identified, but in clinical practice approximately 20 species are identified. Among them are:
- specific markers that are likely to indicate malignant process specific location (for example, in the intestines);
- nonspecific markers indicating the presence of malignancy, regardless of its location, or having low sensitivity for intestinal cancer.
To judge the prevalence of the process and the effectiveness of treatment, the concentration of both tumor markers is determined.
Specific
There are no ideal markers that accurately indicate the presence of a malignant tumor in the intestine. The most sensitive ones are:
- Carcinoembryonic antigen (CEA). It belongs to the class of oncofetal markers. Normally, it is produced in the fetus in the stomach and intestines. After birth, CEA production decreases. Its concentration increases significantly in colorectal cancer.
- CA 19-9. This glycoprotein is found in the fetal epithelium of the intestines, stomach, and pancreas. This tumor marker is less specific. Its concentration increases significantly in pancreatic cancer and cholestasis.
- CA 72-4. Its level rarely increases in inflammatory diseases and increases significantly in cancer of the stomach and intestines.
- Tumor-M2-pyruvate kinase (Tu M2-PK). The enzyme is produced in the gastrointestinal tract by proliferating malignant cells. Has 70% specificity for colorectal cancer. Its concentration depends on the stage of the disease. The main feature is that this tumor marker is determined not only in the blood, but also in the feces.
To identify the extent of the process and the presence of metastases, an immunological study of nonspecific tumor growth markers is performed.
Assessment of the level of tumor markers in primary diagnosis bowel cancer is not always justified. The values of tumor markers are not always directly related to the disease being diagnosed. An increase in the indicator may have nothing to do with bowel cancer. And on the contrary, low level a tumor marker does not guarantee the absence of a malignant tumor. An accurate diagnosis can only be made after full examination from a specialized specialist.
In oncology, tumor markers are used primarily to monitor the patient's condition. If during the initial examination the patient had a high level of a tumor marker, its growth is subsequently monitored. After the tumor is removed, its concentration in the blood decreases sharply. Repeated growth of the tumor marker indicates tumor recurrence.
Nonspecific
Nonspecific tumor markers of intestinal cancer include those substances whose concentration rarely increases in this disease, and those that increase in any type of tumor:
Referral for tumor marker research is provided by oncologist. It is the doctor who determines which of the specific and nonspecific indicators of malignant formations are important for diagnosing intestinal cancer and differentiating the disease from benign diseases.
Analysis
For analysis, blood is taken from a vein, and stool analysis is also possible. The analysis is carried out in a laboratory equipped for immunological studies. Mostly they are located at oncology centers. Private laboratories also determine cancer markers, but some tests may not be performed there. In order not to waste time, it is better to first find out what tumor markers are determined there.
Before the study you need to prepare:
Before submitting stool for determination of Tu M2-RK, you must not:
- undergo X-ray and endoscopic examination;
- use laxatives;
- give enemas.
Feces are collected in a sterile container.
For correct diagnosis and assessing the effectiveness of treatment, it is not enough just to identify the presence of tumor markers in the blood. The data obtained must be interpreted correctly.
Decoding indicators
There are many methods for determining tumor markers; their concentration is measured in different units, therefore normal values may vary in different laboratories. When monitoring the effectiveness of treatment, it is necessary to compare indicators.
To make the assessment more accurate, repeat tests are taken in the same laboratory.
| Tumor marker | Norm |
| REA |
|
| SA 19-9 | up to 37 IU/ml |
| SA 72-4 | up to 4 IU/ml |
| Tu M2-RK |
|
| SA-125 |
|
| SA-242 | up to 21.7 U/ml |
| SCC | up to 2 ng/ml |
| AFP |
|
| CYFRA 21-1 | up to 2.3 ng/ml |
| Pj-globulin | up to 5 µg/ml |
| TRA | up to 120 units/ml |
| TPS | up to 120 units/ml |
When interpreting the obtained data, not only the concentration of tumor markers is taken into account, but also their specificity and sensitivity. Some indicators are also influenced by other factors. CEA is increased in smokers and alcoholics.
The concentration of tumor markers increases slightly in inflammatory diseases (pancreatitis, hepatitis, Crohn's disease). Therefore, if tests reveal increased content tumor markers, you should consult an oncologist or gastroenterologist.
What to do if tumor markers are detected?
Increased concentration Tumor markers are in no way a criterion for diagnosing cancer. These substances may appear in greater quantities in the blood during benign diseases. Moreover, the greatest diagnostic value has a determination of the concentration of tumor markers in dynamics: their number decreased or increased after surgery, conservative therapy. Such screening studies are carried out monthly, if metastases are suspected, to monitor the growth of a tumor that cannot be removed for one reason or another.
To diagnose intestinal cancer, especially in the early stages, analysis of tumor markers is not enough. If only because these substances enter the bloodstream during intensive tumor growth.
A doctor will suspect bowel cancer when a patient comes to him with the following alarming symptoms:
- sudden weight loss;
To identify malignant intestinal tumors, the following is carried out:
The most accurate data is obtained during and subsequent study of tissues and cells -. It allows you to determine the stage of cancer and therapeutic strategy.
What to do if the diagnosis of cancer is confirmed?
The final diagnosis of bowel cancer is not a death sentence. As soon as the doctor has identified a malignant formation, treatment must begin. It is strictly not recommended to visit grandmothers, grandfathers, herbalists, and psychics. This way you can survive to stage 4 with metastases and painful death.
Cancer, especially in the initial stages, is successfully treated with:
- operations;
- radiation therapy;
- drug treatment (chemotherapy, cytostatics, hormonal drugs).
Moreover, at the initial stages of the disease, organ-preserving operations are performed.
On late stages resort to radical methods therapy (resection), and additional radiation and chemotherapy are required.
If it is not advisable to undergo surgery for a malignant tumor or all possible treatment methods have been exhausted, they resort to palliative care.
The success of therapy largely depends not only on the stage of the disease, but also on the patient’s attitude towards treatment. If you initially imagine yourself to be terminally ill, then positive effect it's harder to wait.
The topic of cancer is increasingly affecting people young, which cannot but upset. The insidiousness of oncological processes lies in the fact that it is not always possible to detect a tumor at stages 1-2. Only an early examination helps to identify pathology and begin treatment in a timely manner. For example, intestinal tumor markers, breast, ovaries and many other localizations make it possible to suspect oncology at the initial stage.
When appears pain syndrome, this indicates the spread of the lesion to the nerve endings. Subsequently, metastasis is observed, which worsens the prognosis for recovery.
What are intestinal tumor markers?
Today, in addition to instrumental diagnostic techniques(ultrasound, radiography, computed tomography and magnetic resonance imaging), there is such a way to identify a tumor as assessing the level of tumor markers.
They are a collection of protein elements of a specific origin that are produced in response to activity. Similar protein structures can be found in urine, feces or blood, and therefore are used both to identify a malignant focus and to assess the effectiveness of the treatment used.
What are the tumor markers for colon cancer and why do you need to take them?
Intestinal tumor markers are characterized different structure, therefore, they can be specific, when an increase in their level means the presence of a tumor of a certain location, and nonspecific, indicating the development of an oncological process without an exact location.
Of the specific proteins indicating intestinal lesion, highlight:
- CA 72-4;
- Tu M2-RK;
- CA 242.
As for the less specific laboratory parameters, it is worth noting alpha-fetoprotein, CA-125, CA 19-9, CYFRA 21-1, SCC and LASA-P.
Thanks to tumor markers, it becomes possible to:
- Detect the exact location of oncology.
- Provide control over healing process(a decrease in the level of specific proteins indicates the effectiveness of the therapy; an increase, on the contrary, emphasizes incorrect treatment tactics).
- in the initial stages.
- Help determine probability reappearance neoplasms.
It would seem that tumor markers are an ideal study, but it must be remembered that they only indicate possible localization, confirmation of which is the identification of the lesion using ultrasound or tomography.
Besides, slight increase indicators can also be observed in healthy people. In this regard, carrying out exclusively analysis for markers is irrational without additional examination.
Norm and price
The cost of such analysis varies depending on their type. On average, one analysis can cost from $10 to $20 US. The execution time is about 4 days.
To correctly interpret the results of a laboratory test, it is necessary to pay attention to the units of measurement, since each laboratory can carry out calculations depending on the equipment available.
The following norms of indicators will be presented in the following units of measurement - “IU/ml”.
- APF – range from 5 to 10;
- CA 242 – 0-30;
- REA should be absent or below 5;
- CA 19-9 should not exceed 40;
- CA 72-4 has a maximum value of 6.3.
The listed analyzes are used for initial examination on intestinal pathology and analysis of treatment dynamics.
Decoding
To correctly understand what the quantitative composition of an indicator means, you need to know what each “protein marker” means, how it is characterized and what it indicates:
- Carcinoembryonic antigen or CEA for short:
Under physiological conditions, its production occurs by cells gastrointestinal tract fetus during intrauterine development. If its levels exceed the norm, this indicates damage to the intestine, namely the large section. In addition, it can be used to predict the stage of malignancy, the volume of the lesion and the prognosis. CEA is also used to assess the correctness and effectiveness of treatment. It allows you to assess risk re-development disease even before the first clinical signs appear.
- SA-242:
Malignant degeneration of cells of the colon and pancreas is indicated by an increase in CA-242. It is also used to determine the likelihood of relapse.
- SA 19-9:
A less specific marker is carbohydrate antigen (CA 19-9). Its organ affiliation is extremely low, since an increase in its level may mean the presence of oncology in the stomach, esophagus, gallbladder, ovaries or colon. It is used to evaluate the effectiveness therapeutic techniques and for the purpose of early detection of tumor re-development.
- SA 72-4:
Usually absent in practically healthy people. Exceeding it upper limit The norm is observed in colorectal cancer, malignant lesions of the stomach or lungs. This indicator is used only as an additional examination in parallel with the analysis of other, more specific, oncoproteins.
- TuM2-RK:
Refers to a group of nonspecific indicators that are used for the purpose of initial detection of a tumor or assessing its risk. It only reflects the state of metabolic processes in cancer cells.
It should be noted that when identifying an oncological lesion of the intestine, the doctor does not prescribe an analysis of each tumor marker. It's quite expensive. 1-2 markers are selected to suspect a tumor or confirm the diagnosis. Intestinal tumor markers can be used both for early detection of the disease and in combination with other laboratory and diagnostic techniques.
Intestinal tumor markers - the number of types of proteins that do not exceed the established threshold in a person who does not have malignant neoplasms. A cancerous tumor increases the concentration of substances. During laboratory testing, tumor markers can identify malignant cells.
Purpose of the procedure
Oncology at the first stage of development of a pathology that does not have pronounced symptomatic signs is diagnosed only with regular medical examination. Detection of colon and rectal cancer at the initial stages of the spread of malignant cells is possible using tumor markers.
The first symptoms indicating abnormalities in functioning gastric tract, are:
- a sharp decrease in body weight;
- loss of appetite;
- weakness, increased fatigue.
Indications for the procedure to determine intestinal tumor markers are the presumptive diagnosis of rectal and colon cancer, assessment of the results of prescribed treatment, and the likelihood of relapse of the pathology during remission.
Testing allows us to identify the presence cancer, location of the malignant tumor, degree of organ damage digestive system, evaluate the action medications, control the process of the therapeutic course.
Classification
To determine the nature of the pathology, there are types of intestinal tumor markers:
- specific;
- nonspecific.
Tumor markers of the first group show the location of intestinal cancer and the degree of damage to the organ. An increase in the concentration of nonspecific proteins reveals the presence or absence of a malignant neoplasm.
Specific
Tumor markers of the first group of substances for rectal cancer include:
- carbohydrate antigen;
- carcinoembryonic antigen;
- tumor marker of choice.
An increased concentration of carbohydrate antigen determines the initial stage of development cancerous tumor rectum, colon, pancreas, ovarian region, gall bladder. If the amount of tumor marker CA 242 exceeds the norm, an immunological study is performed to detect the development of a neoplasm. The increased concentration of carcinoembryonic antigen determines the degree of organ damage in rectal cancer, formation parameters, and the dynamics of tumor growth.
The study of tumor markers makes it possible to evaluate the progression of pathology, the effectiveness of prescribed treatment, and the likelihood of disease relapse. To identify small cell cancer in the lungs and large intestine, an analysis is done to detect the amount of specific proteins CA 72-4.
The tumor marker of choice determines the nature and rate of progression of the cancer tumor. Determination of metabolic processes and the level of metabolism of malignant cells reveals the spread of tumors of the stomach and intestines. The amount of Tu M2-PK proteins gives an idea of the presence of oncology, the degree of progression of the pathology, and the spread of metastases.
Nonspecific
Tumor markers of the gastrointestinal tract that do not provide information about the location of tumor formation are:
- CA 19-9;
- CA 125;
- CYFRA 21−1;
- LASA-P.
An increased concentration of the tumor marker alpha-fetoprotein, CYFRA 21−1, diagnoses the presence of cancer of the rectum and organs respiratory system. An indicator of the carbohydrate antigen CA 19-9, exceeding the norm, indicates the development of an internal pathological process without establishing the localization of malignant cells.
CA 125 – the presence of cancer of the sigmoid process, the ovarian region. The level of concentration of the squamous cell tumor marker SCC determines the formation of a tumor in the rectal canal. An increase in LASA-P indicators indicates damage to other parts of the digestive system.
Features of the procedure
To determine the concentration level of specific, nonspecific intestinal tumor markers, you need to donate blood. Biological material is collected in the morning on an empty stomach to ensure accurate results. For the Tu M2-PK tumor marker, stool excreted from the body is required naturally without the use of laxatives or microenemas. The accuracy of the result is guaranteed complex analyzes due to individual sensitivity to the components of the research material.
To do it correctly, combined procedures are required:
- carbohydrate CA 242 and carcinoembryonic antigen;
- CEA and nonspecific protein CA 19-9;
- carbohydrate CA 242, CA 19-9 and carcinoembryonic antigen.
The first combination of tests determines cancer of the stomach, the second - of the rectum, and the complex - of the large intestine. An increase in the concentration of cancer proteins, called specific proteins, may indicate pathological processes in the liver and parts of the digestive system that are not related to a malignant tumor (Crohn's disease).
The results of the study are affected by internal non-cancerous diseases, pregnancy, and non-compliance with the rules of preparing the body for the delivery of biological material for examination of the intestines.
The peculiarity of the procedure is the connection of a specific protein indicator with a specific cancer disease, the site of cancer formation. The diagnosis of the progression of damage to the organ of the digestive system and the choice of the method of endoprosthetics depend on determining the nature of the internal pathological process.
Preparing for analysis
If intestinal cancer is suspected, blood from a vein is donated for tumor markers, following the rules for preparing for laboratory analysis:
- strict diet: exclusion from the diet of fast food, processed foods, fatty, fried, salty, smoked foods 7 days before the scheduled procedure;
- ban on tobacco use, alcoholic products for the period of medical therapy;
- refusal of food, carbonated drinks, juice, strong tea, sweet coffee 8 hours before blood sampling;
- good sleep, rest.
Before donating blood, you need to prepare in advance: the accuracy of test results, called laboratory tests, is influenced by lifestyle and diet. Bottom line laboratory research blood are known after 1-2 days, feces - 7 days.
Tumor marker indicators
Deciphering the results of the level of concentration of tumor markers helps to establish the presence of a pathological process in the organs of the digestive system.
The normal amount of proteins in the blood is:
- CA 242- 0-30 IU/ml;
- CEA – 0-5.5 ng/ml;
- CA 72, LASA – P – 3.8-4 IU/ml;
- Tu M2-PK – 1.5 IU/ml;
- AFP – 15 ng/ml;
- CA 19-9 – 3.4 IU/ml;
- CA 125 – 2.5 IU/ml;
- CYFRA 21−1 – 3.3 IU/ml;
- SCC – 1.5 ng/ml.
Exceeding the norm for the carbohydrate antigen CA 242 means the formation cancer cells in the pancreas, large intestine. The stage of development of the disease is determined through a structural study of the okomarker. Early diagnosis increased levels of CA 242 guarantee positive dynamics in the treatment of cancer.
The presence of cancer is indicated by an excess of CEA concentration. Specific protein indicator, more than 5.5 units – a sign pathological change structures of the colon.
Independently determine the presence of organ damage based on data clinical trial impossible. Normalized indicators of the concentration of specific and nonspecific proteins in profile medical institutions and private laboratories differ. This is due to the characteristics of the equipment used in the research.
Accurate detection of cancer is possible with comprehensive definition indicators of intestinal tumor markers. Prescribing a combined analysis of specific and nonspecific proteins increases the likelihood of a correct diagnosis. The types of laboratory tests are determined by the doctor depending on the purpose of blood sampling: establishing the presence of a tumor, the location of the spread of cancer cells, monitoring the progression of pathology.
Benefits of diagnostics
It is possible to determine pathologies in the area of the rectum, colon, and pancreas at the initial stage only based on the results laboratory tests to study the amount of cancer proteins in the blood. Symptoms of cancer at the first stage of development of the disease are not pronounced. Establishing the concentration of substances in the body at early stage allows you to assign timely treatment malignant tumor.
Donating blood for tumor marker tests during the therapeutic course is necessary to control the spread of cancer cells. Carrying out the procedure regularly after the end of treatment allows for timely detection of a possible relapse of the disease. Optimal time delivery of biological material – no more than 90 days.
The negative side of using the method when blood is used is the lack of specificity of cancer proteins. An increased concentration of a substance does not necessarily indicate the formation of pathological processes in the rectum. Increased rates are observed during inflammation, structural changes tissues not associated with distribution malignant neoplasms.
A high level of intestinal tumor markers may indicate the final stage of cancer development, when the only option for helping cancer patients is endoprosthetics.
Information on our website is provided qualified doctors and is for informational purposes only. Don't self-medicate! Be sure to consult a specialist!
Gastroenterologist, professor, doctor medical sciences. Prescribes diagnostics and carries out treatment. Study Group Expert inflammatory diseases. Author of more than 300 scientific papers.
Using intestinal tumor markers, doctors are able to analyze their content in the patient’s blood to identify not only the tumor itself, but also the stage of the disease, as well as its nature. Cancer affects people every day a large number of people, and gastrointestinal cancer is no exception. Greatest danger oncological tumors lies in the difficulty of early diagnosis.
Diagnosis of cancer in the initial stages is rare, since the symptoms of oncology appear too late to suspect pathology. Sometimes it is possible to suspect oncology in a timely manner and refer the patient to determine intestinal tumor markers in the early stages during a preventive examination.
What are tumor markers
Tumor markers are certain proteins found in the blood. IN in good condition their presence can also be observed in a healthy person, but only the concentration does not exceed the established norms. In the case of a cancerous event, e.g. colorectal cancer, malignant cells begin to synthesize the production of this protein, as a result of which the level of tumor markers in the blood increases. When colon tumors form, tumor markers can be used to identify the location of tumors and determine the stage of development.
Main types of gastric tumor markers
To know which tumor markers are tested for intestinal cancer, it is worth familiarizing yourself with the two main groups for determining intestinal tumor markers:
- Specific - allow you to identify a tumor in a specific area of the body;
- Nonspecific - detect a cancerous tumor, but do not indicate its location.
The group of specific tumor markers includes the following:
- Carcinoembryonic antigen (CEA) is a tumor marker for colorectal cancer. When studying the results of this analysis, it is possible to predict the dynamics of tumor growth, calculate the period of its progression and obtain data on the nature of oncology. Using the CEA marker, the effectiveness of cancer treatment is assessed and the risk of developing a relapse of malignant cells is determined.
- CA 242 (carbohydrate antigen) - a tumor marker can show the presence of a tumor in the area of the large intestine, pancreas and rectum during the early stage of development. This study allows you to predict the development of a new tumor formation in three or even five months.
- CA 72-4 - this study is often carried out in conjunction with CEA. This antigen can be found in malignant cells of the colon and lungs in the case of small cell carcinoma. An increase in the level of this protein may also indicate the development of colorectal cancer.
- Tu M2-PK is a tumor marker that allows you to determine all metabolic processes occurring in cancer cells. This indicator is also called “selection marker”, since its feature is the lack of great specificity when choosing specific body affected by the disease. This test is used for certain metabolic parameters. Can detect oncological tumors in the gastrointestinal tract in the early stages of progression.
The group of nonspecific tumor markers consists of:
- alpha-fetoprotein (AFP) - a marker manifested as an increase in α-fetoprotein indicates the presence of a tumor formation in the sigmoid and rectum;
- CA 19-9 is a tumor marker that detects oncological pathologies of the pancreas, esophagus, gallbladder and its duct, as well as the large intestine;
- CA 125 - using this indicator, you can determine the occurrence of an oncological process in the sigmoid colon;
- CYFRA 21-1 - an increased level of this tumor marker helps determine the presence of a cancerous tumor in the rectum;
- SCC - detects the presence of cancer in the rectal canal;
- LASA-P - an increase in antigen levels signals possible availability malignant neoplasms in other organs and parts of the intestine.
The use of all these intestinal tumor markers makes it possible to detect the disease earlier than the first symptoms appear. But it is worth understanding that if the results show deviations from the norm in the level of antigens in the blood, which are released more during cancer, this does not yet give full confidence in the presence of oncology. To the patient when high level antigen in the body, it is necessary to undergo additional examination and diagnostics.
Preparing for diagnosis
To determine the level of tumor markers, the biological material used is blood. It is necessary to donate blood for tumor markers in the morning, having previously excluded eating food eight hours before the test. It is worth noting that before donating blood to analyze the level of tumor markers for intestinal cancer, drinking drinks such as juices, tea or coffee is also prohibited. Doctors recommend drinking only boiled water.
After donating blood, the result will be ready within one or two days. When conducting a study to determine the level of CA 72-4 protein, it is necessary to take into account the patient’s possibility of taking biotin, because if its dosage is more than 5 mg for one day, then blood for analysis is prohibited within eight hours after the last use of the drug.
To determine the level of Tu M2-RK, a stool analysis is performed, and the biological material should not be removed using enemas or laxatives, but obtained only naturally. In this case, the result of such an analysis can only be ready after seven days.
How is the analysis done?
Tests for intestinal tumor markers can be carried out in absolutely any laboratories, both public and private. Determination of the level of colorectal cancer markers is carried out using the patient's blood as a biological material. To prepare for being tested for cancer, you must adhere to the following rules:
- Avoid eating 8 hours before donating blood;
- donate blood in the morning;
- A few days before the test, it is recommended to exclude sweet, fatty, smoked and fried foods from the diet.
- Drinking tea, coffee or other drinks before donating blood is also prohibited.
Blood tests are taken from a vein, after which its study can last for seven days. If patients have previously been diagnosed with tumors, they need to be tested for tumor markers regularly.
The results of a study of one tumor marker cannot be accurate, so the results of indicators that are carried out in combination are usually taken into account. For example:
- marker CA 242 and CEA - allows you to identify crustacean neoplasms in the stomach;
- CA 19-9 together with CEA - allows you to detect colorectal cancer;
- combination of CA 19-9, CA 242 and CEA - used in the case of colon cancer.
To detect pyruvate kinase produced by malignant cells of the gastrointestinal tract, it is necessary to study Tu M2-PK. It is worth noting that an increase in the concentration of tumor markers in the blood may not always indicate the presence of cancer. Increased level CEA is often observed in the case of diseases of the veins and pathological processes occurring in the liver, for example, in the case of cirrhosis or Crohn's disease. Therefore, the results of any biochemical tests should always be confirmed by data from other studies (MRI, CT, ultrasound).
Decoding the results
First of all, it is worth noting that the results of tumor marker studies can be interpreted differently, depending on the chosen laboratory clinic. Different clinics may use different units of measurement. The data obtained may vary within generally accepted norms:
- CEA - 0 IU/ml;
- CA 242 - 0-30 IU/ml;
- CA 19-9 - up to 40 IU/ml;
- CA 72-4 - up to 6.3 IU/ml.
In addition to an increase, in some cases there may be a decrease in the level of these substances. This indicates the absence cancers, but may indicate pathologies that can form in organs such as the liver or kidneys. The indicators of one study cannot be an accurate confirmation of the presence of oncology, therefore, to diagnose accurate diagnosis the patient is prescribed comprehensive examination. For example, a tumor marker for colon cancer is carried out in combination with RAE, CA 19-9 and CA 242.
Norms and deviations
When conducting research for the presence of intestinal cancer, specialists must compare test results with generally accepted norms for healthy people. If a deviation from the norm is observed, this signals possible damage to some part of the intestine by malignant cells. Deviations from the norm are calculated from the concentration of antigen in the blood. If the value is too increased, the patient may develop pathology. In order to promptly detect cancer of the stomach or other area of the gastrointestinal tract, it is necessary to undergo tests for tumor markers annually for the purpose of prevention. Cancer treatment is much more effective if the disease is detected at an early stage of progression. Helping cancer patients is the work of cancer patients themselves.
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