What are tumor markers? These are specific substances in the blood of those people who are most likely to have cancer. The technique for detecting cancer is still imperfect. But in 75% of cases, the presence of tumor markers in the blood clearly indicates the growth and spread of the tumor.
These substances are similar to body signaling. The most basic marker of a tumor in the stomach is the CA 72-4 protein. However, for an accurate diagnosis, at least 3 gastrointestinal markers must be passed.
What are oncology markers?
Oncology markers are proteins produced by tumor cells. This is now the most advanced method for early detection of cancer.
In some cases, the analysis may produce a false positive or false negative. But it is impossible to make a diagnosis only on the results of tumor markers. An oncologist who interprets your findings should be aware of all the latest clinical research.
Recently, specific non-coding ribonucleic acids (RNAs) and human chorionic gonadotropin (hCG) have also been referred to markers. HCG hormone is detected in ovarian cancer in women and testicles in men.
In this article, we will consider only gastrointestinal markers. How to take these tests? And how much will it be?
First screening. What tests are being tested?
Screenings are carried out to determine the risk group. Tests of this kind are not diagnostic. However, they are necessary in order to understand whether further research is needed, whether a person should spend money and time on other tests, analyzes and complex studies.
Primary tumor markers are proteins whose enzymes are the waste products of the tumor. They are determined first of all, since they have great sensitivity. CA 15-3, CEA, CA-50 and an additional analysis — a marker for pancreatic carcinoma CA 242 — are used. The gastric tumor marker CA 72-4 is the most informative for diagnosis.
How were tumor markers discovered?
For the first time, scientists such as Leo Zilber and Harry Izrailevich Abelev discovered that protein alpha-protein can indicate liver cancer. They accidentally discovered these substances by studying the composition of tumor hepatocytes (liver cells).
Alfaprotein is a protein that is produced by the placenta. Researchers absolutely could not assume that they would find it in these cells. They searched for the virus, and found the first liver tumor marker.
Cancer of the digestive tract 72-4
Consider each of the markers in more detail. What are tumor markers for stomach cancer? So, Tumor-associatedglycoprotein 72–4 is a marker for carcinoma. It can be a tumor of the stomach, pancreas or lungs. A persistent increase in the blood of these glycoproteins indicates the presence of either a benign or malignant tumor. But it is also present in pregnant women in the body. Venous blood is taken for analysis. The reference value is up to 6.9 u / ml.
Unfortunately, not a single marker will accurately determine the location of the tumor. Only a council of experienced and highly qualified oncologists can make a diagnosis after collecting an anamnesis and having the results of all analyzes.
CEA marker. Decryption analysis
When blood is donated to the tumor markers of the intestine and stomach, CEA is determined first. CEA tumor marker - cancer-embryonic antigen. This is a primary marker. This is a substance that is produced by the embryo in fairly large quantities. But when the baby is already born, its presence in the blood is an anomaly.
CEA gastric tumor marker has a rather high sensitivity, but it does not determine the type of oncology and stage of development. If suddenly a marker is detected, then several related tests are assigned. The researcher will be sent to the delivery of other tumor markers: the esophagus and stomach, colon and pancreas. And also prescribe gastroscopy.
Marker SA-50
The gastric tumor marker CA-50 is mainly used for the diagnosis of pancreatic relapse and metastases. CA-50 is a sialoglycoprotein from a chemical point of view. If the oncologist needs to collect more information about the patient’s condition, he also prescribes this analysis. This protein can be detected both in biological fluids and on the surface of an organ epithelium.
Indications for blood donation for tumor markers
What are marker tests for? What can tumor markers indicate?
- Blood is given for analysis for the purpose of primary diagnosis.
- If the diagnosis is already clear, then to make a prognosis of treatment.
- To assess the performance of treatment already performed. After a course of chemotherapy, tumor markers are required to be resubmitted.
- In order to identify metastases in the body a few years after successful treatment.
Who needs primary blood tests for gastric tumor markers? First of all, tests are prescribed for people with high cancer risks. These are those people who already have such diseases:
- severe atrophic gastritis;
- peptic ulcer;
- adenomatous polyps in the stomach.
Increased risk in former surgery patients who removed part of the stomach.
Oncologists know how quickly the Correa cascade progresses. Within 10-15 years, cancer develops from atrophic gastritis in this chain of diseases - atrophy - metaplasia - dysplasia - cancer.
The risk is also high if there are close relatives suffering from any type of tumor, and who work in adverse conditions (increased radiation level).
When and how are tests done?
All tests for tumor markers of the stomach are given in the morning, on an empty stomach. Restrictions in food the day before the analysis are also present.
What are the requirements for the result to be as reliable as possible?
- Do not eat 12 hours before analysis.
- If vitamin Biotin is taken, you must stop using it for 8 hours.
- 48 hours before blood donation, there is nothing fried, oily or spicy. Only boiled, steamed food that does not cause mucosal irritation.
- You can also not smoke, drink coffee, tea or even mineral water. Drinking only clean water is permissible.
Smoking patients are warned that cigarettes are also not allowed several hours before the procedure itself. Smoking can also affect the result. By the way, tobacco smoke contributes to the development of stomach cancer. Since carcinogens get directly into the body with it. And besides, nicotine enhances the production of hydrochloric acid.
Analysis Standards and Deviations
After the blood enters the laboratory, its samples in flasks are placed in a special medical centrifuge and the serum is separated from the plasma. The speed of the centrifuge is somewhere around 1500-3000 rpm, while a certain temperature is observed. Then the laboratory assistants conduct a special test with isolated serum and get the results.
3 main markers are used to determine gastric cancer. This is CEA, CA 19-9, CA 72-4. Sometimes it is required to donate blood to additional markers — CA 242, CA 125 and ACE. It must be said that the sensitivity of the CA 242 test is higher than, say, CA 19-9, but CA 242 may indicate intestinal and pancreatic cancer. You can find out exactly only after a comprehensive study.
Each clinic has its own standards, since different units of measurement are used. But there are general parameters in the world, accepted as a norm, that are based on them when interpreting the results of the analysis.
Which results are the norm, which exceed the norm?
- CEA - the norm is not more than 8 ng / ml.
- CA 242 - up to 30 IU / ml.
- for CA 72-4 - 22-30 IU / ml.
- CA 19-9 - up to 40 IU / ml.
- ACE (marker of liver cancer) - 5-10 IU / ml.
It is completely permissible to take tests on your own initiative, without a doctor's referral. But it is forbidden to interpret the figures without a medical consultation. A person without special knowledge of modern oncology cannot judge his health.
Results are above normal. Should I panic?
So what to expect if the stomach tumor marker is elevated? If a person is at risk and informed about a too high level of marker CA 72-4 or CA 19-9, you should not consider yourself immediately sick. Data obtained after one or two analyzes is not enough.
In addition to identifying markers, much more research needs to be done. Additional tests either confirm or refute the hypothesis of cancer. By itself, the tumor marker of the stomach can give a false-positive result.
After there are suspicions of oncology, you need to undergo an MRI, ultrasound and gastroscopy. Without gastroscopy, no diagnosis can be considered correct.
How often to take blood for analysis?
If a person already had some kind of cancer, he needs to watch more often so as not to miss the resumption of tumor growth. It is recommended that such people once every 6 months donate blood precisely to one specific marker. Just to find out if there is a relapse. However, when there was no tumor, but the person is at risk, he should also be checked every few years. You can not miss the development of the first stage. This is the right time for treatment.
For completely healthy people who are not at risk, there is no need to donate blood to the tumor markers of the stomach. But for your own peace of mind, you can pass one analysis in the nearest private clinic, without direction.
Analysis Prices
The cost of the tests differs in different clinics. And each tumor marker has a price. You need to count on an average price from 1000 to 2500 rubles. Treatment then will cost much more, so it’s better to do everything in a timely manner, without delaying the delivery of tests until better times.
In the end
So, modern tests have insufficient specificity. That is, no one can determine exactly where the cancer is and what stage it has. But doctors rely on tumor markers in order to determine the effectiveness of the treatment.