There is no ideal cure for cancer and that is why it is so important to detect cancer in advance or at an early stage. This is what blood tests are used for, which consist in determining the level of tumor antigens, i.e. tumor markers.

Tumor markersfacilitate bothcancer detectionand treatment monitoring. Each year over 100,000 Poles develop cancer. The most common ones include lung, breast and cervical cancer.

The statistics remain inexorable - every year a town the size of Jelenia Góra disappears from the demographic map of Poland. In this respect, we significantly deviate from European and world standards. While the cure rate of cancer in the USA is on average 63%, in Western Europe 45%, in Poland it is only 30%. Where is the source of these disproportions? Certainly one of the most significant factors is the fact that we usually visit a doctor when the disease is advanced.

In the early phase, treatment begins less than 20 percent. sick. Despite the fact that doctors have a range of effective treatment techniques, it is often too late. One of the tools used in the fight against cancer are tumor markers, also known as companion antigens.

What are tumor markers?

These are substances found in the blood of many people with cancer. A marker is a factor that is produced only by neoplastic cells, or one that cells produce in large enough amounts that its concentration exceeds a certain threshold value considered pathological.

Individual markers appear in the patient's blood at certain points in the development of the neoplasm, not only when the disease arises, but also during the death of the neoplasm. Markers of vanishing tissues are, for example, the numeral-21 marker found in lung cancer. Therefore, antigens can be used in all stages of the fight against neoplastic disease, from its detection, through determining the stage of its advancement, to assessing the effectiveness of the treatment.

Important

Reference values ​​of some tumor markers:

  • CA 125<35 U/ml
  • AFP<6 IU/l
  • CA15-3<30 U/l
  • CEA <4 ng/ml
  • DOG<4 ng/ml
  • hCG<10IU/l

What can the result of an increased level of cancer antigen show, apart from cancer?

  • CEA - inflammation, liver cirrhosis, gastric ulcer, heavy smoking
  • CA 125 - pregnancy, menstruation test, endometriosis, inflammation of the reproductive organs
  • AFP - chronic infection, liver damage

Most studied tumor markers

Testing the tumor marker level is simple and not very troublesome. Their level is determined in venous blood. Currently, the most common level is:

  • CA 125 - occurs in approximately 80% of women with ovarian cancer. In he althy women, the concentration of this antigen does not exceed 35 U / ml and depends on the hormonal status. Determining the level of this marker at the beginning of treatment is important because the lower it is, the greater the chances of obtaining a permanent cure.
  • AFP - a significant increase in the level of this antigen occurs in cancers of the liver and some testes.
  • CA 15-3 - an antigen used especially in the diagnosis of advanced breast cancer. It is often used to detect metastasis. The drawback of the marker is its imperfection in detecting less advanced cancer.
  • CEA - high levels of antigen are found very often in patients with colorectal cancer, therefore it is used as one of the elements of disease monitoring. CEA is also recognized as a universal determinant of metastases (regardless of the organ of the disease).
  • PSA - an antigen characteristic of prostate cancer. It is used as an element supporting disease detection, and also during treatment as a factor determining the effectiveness of therapy.
  • Beta-HCG - occurs in patients suffering from trophoblast diseases (e.g. chorionicoma) and germ cell tumors, mainly in children.

Tumor markers as screening tests?

Screening tests are aimed at finding patients in the early stages of the disease who do not have any symptoms. They include people with the highest risk of developing the disease, therefore they are addressed to specific age groups (e.g. personal invitations to smear tests sent to women aged 25 and over).

The main features of a good screening are its sensitivity and specificity. Sensitivity is the test's ability to detect disease, while specificity tells us about the test's ability to identify he althy people. A good screening test should be long-term and massive. According to estimatesonly when 75% of the invited group of women apply for a cytology test will it be possible to reduce the death rate from cervical cancer by 25%.

Unfortunately, scientists note that most cancer antigens do not meet the basic conditions to be used as screening agents. Very often, elevated levels of one of the markers do not indicate cancer and may occur in many other diseases, e.g. increased CA 125 levels may be caused by inflammation of the ovaries. Due to the limited sensitivity and diagnostic specificity of the markers known to us, their usefulness is the subject of numerous discussions in the medical community. They are only used as an aid with other tests.

Probe

Category:

Research