What are tumor markers? These are specific substances in the blood of those people who are most likely to have cancer. The method of cancer detection 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 like signaling the body. The CA 72-4 protein is considered the most important marker of a stomach tumor. However, for an accurate diagnosis, at least 3 markers of the gastrointestinal tract must be passed.
What are cancer 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 test may give a false positive or false negative result. But it is impossible to make a diagnosis only on the results of oncomarkers. The oncologist who interprets your results should be aware of all the latest clinical research.
Recently tomarkers also include specific non-coding ribonucleic acids (RNA) and human chorionic gonadotropin (hCG). The hormone hCG is detected in ovarian cancer in women and testicular cancer in men.
In this article, we will consider only markers of the gastrointestinal tract. How to pass these tests? And how much will it cost?
First screening. What tests are given?
Screenings are done to determine the risk group. Tests of this kind are not diagnostic. However, they are necessary 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 in the first place, as they have greater sensitivity. They use CA 15-3, CEA, CA-50 and an additional analysis - a marker for pancreatic carcinoma CA 242. The most informative for diagnosis is the gastric oncomarker CA 72-4.
How were tumor markers discovered?
For the first time, scientists such as Lev Zilber and Garry Izrailevich Abelev discovered that alfoprotein may indicate liver cancer. They accidentally discovered these substances while studying the composition of tumor hepatocytes (liver cells).
Alphaprotein is a protein produced by the placenta. The researchers had absolutely no idea that they would find it in these cells. They were looking for a virus, but they found the first liver tumor marker.
Gastrointestinal tumor marker72-4
Let's consider each of the markers in more detail. What tumor markers are tested for stomach cancer? So, Tumor-associated glycoprotein 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. Reference value - up to 6.9 units/ml.
Unfortunately, no marker will accurately determine the location of the tumor. The diagnosis can only be made by a council of experienced and highly professional oncologists after collecting an anamnesis and having the results of all tests.
REA marker. Analysis transcript
When blood is donated for oncomarkers of the intestines and stomach, the first thing is determined by CEA. The tumor marker of CEA is a cancer-embryonic antigen. This is the 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.
The gastric tumor marker CEA has a rather high sensitivity, but it does not determine the type of oncology and the stage of development. If suddenly a marker is detected, then several concomitant analyzes are assigned. The subject will be sent for the delivery of other tumor markers: the esophagus and stomach, colon and pancreas. They will also prescribe a gastroscopy.
Marker SA-50
The gastric tumor marker CA-50 is mainly used to diagnose pancreatic recurrences and metastases. CA-50 is a sialoglycoprotein chemically. 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 the organ epithelium.
Indications for donating blood for tumor markers
What are the purposes of testing for markers? What can tumor markers indicate?
- Blood is donated for analysis for primary diagnosis.
- If the diagnosis is already clear, then to make a prognosis of treatment.
- To evaluate the performance of the treatment already performed. After a course of chemotherapy, tumor markers must be taken again.
- To detect metastases in the body several years after successful treatment.
Who needs to take primary blood tests for gastric tumor markers? Tests are given primarily to people who are at high risk for cancer. These are the people who already have these diseases:
- severe atrophic gastritis;
- peptic ulcer;
- adenomatous polyps in the stomach.
Risk increases in former surgery patients who have had part of their stomach removed.
Oncologists know how quickly the Correa cascade progresses. Within 10-15 years, cancer develops from atrophic gastritis according to such a 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 (high levels of radiation).
When andHow are tests done?
All tests for oncomarkers of the stomach are taken in the morning, on an empty stomach. There are also food restrictions the day before the analysis.
What are the requirements for the result to be as reliable as possible?
- Do not eat 12 hours before analysis.
- If you are taking the vitamin biotin, stop 8 hours in advance.
- Do not eat anything fried, fatty or spicy for 48 hours before donating blood. Only boiled, steamed food that does not cause irritation of the mucous membranes.
- You can also not smoke, drink coffee, tea or even mineral water. It is permissible to drink only clean water.
Smoking patients are warned that cigarettes are also not allowed a few hours before the procedure itself. Smoking can also affect the outcome. By the way, tobacco smoke contributes to the development of stomach cancer. Since with it, carcinogens enter the body directly. And besides, nicotine increases the production of hydrochloric acid.
Analysis rates 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 between 1500-3000 rpm, while maintaining a certain temperature. Then the laboratory technicians perform a special test with the isolated serum and receive the results.
There are 3 main markers used to detect stomach cancer. These are REA, SA 19-9, SA 72-4. Sometimes they require to donate blood for 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, butCA 242 may also indicate colon and pancreatic cancer. It is possible to find out exactly only after a comprehensive study.
Each clinic has its own standards, as different units of measurement are used. But there are general parameters in the world, accepted as the norm, and they are based on them when interpreting the results of the analysis.
Which results are normal, which ones are abnormal?
- REA - 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 for liver cancer) - 5-10 IU/ml.
It is perfectly acceptable to take tests on your own initiative, without a doctor's referral. But interpreting the numbers without a medical consultation is prohibited. A person without special knowledge of modern oncology cannot judge his he alth.
The results are above the norm. Should I panic?
So, what to expect if the stomach tumor marker is elevated? If a person is at risk and has been told that the level of the CA 72-4 or CA 19-9 marker is too high, you should not immediately consider yourself sick. Data obtained after one or two analyzes is insufficient.
Besides identifying markers, there is still a lot of research to be done. Additional tests either confirm or disprove the hypothesis of cancer. The stomach tumor marker itself can also give a false positive result.
After suspicions of oncology appeared, you need to undergo an MRI, ultrasound and gastroscopy. Withoutgastroscopy, no diagnosis can be considered correct.
How often to donate blood for analysis?
If a person has already had some type of cancer, he needs to be monitored more often so as not to miss the resumption of tumor growth. It is recommended that such people donate blood for exactly one specific marker every 6 months. Only to see if there's a relapse. However, when there was no tumor, but the person is at risk, he should also be checked every few years. It is impossible to skip the development of the first stage. This is the right time for treatment.
For completely he althy people who are not at risk, there is no need to donate blood for gastric tumor markers. But for your own peace of mind, you can take one test at the nearest private clinic, without a referral.
Prices for tests
The cost of tests differs in different clinics. And each tumor marker has its price. You need to count on the average price from 1000 to 2500 rubles. Treatment will then cost much more, so it’s better to do everything in a timely manner, without postponing the test until better times.
Finally
So, modern tests have insufficient specificity. That is, no one can determine exactly where the cancer is and what stage it has. But it is oncomarkers that doctors rely on in order to determine the effectiveness of the treatment.
