How to determine the cancer by the blood test?
Blood tests and other laboratory tests help doctors to establish a reliable diagnosis. If the oncologist suspects the presence of cancer in the patient, then he is recommended to perform certain tests of the circulatory system.
How can cancer be determined from the blood? Tumor Markers
On the analysis of blood to determine the cancerit is possible by the level of tumor markers, which are special substances of the human body signaling the development of the oncological process. In most cases, a certain marker of a malignant neoplasm is determined in an increased concentration in a particular cancer disease. Some of these substances are found in the blood, while others are concentrated in the urine, cerebrospinal fluid, lymph. The formation of markers of oncology occurs as a result of the vital activity of cancer cells or as a response of the organism to the presence of a pathological neoplasm. Mostly they consist of protein or incorporate mutated genetic information.
Some types of cancer are characterized by the presence of this type of marker, although there is a possibility of a multiple marker relationship. To determine the level of these indicators, along with blood tests, small areas of the cancer can also be sent to the laboratory.
Use of tumor markers
Areas of application of oncology markers include:
- Screening and early detection of cancer
Screening includes the definition of a malignant process in people who do not have any symptoms of the disease. To date, a marker of tumor antibody (PSA) is widely used. The PSA test allows screening of men for prostate cancer.
Early detection of cancer helps to complete tumor therapy at the initial stage, which contributes to a favorable outcome of treatment.
- Diagnosis of cancer
Typically, the blood can determine the number of tumor markers, but this is not sufficient informative method for establishing a diagnosis. The final form of cancer is diagnosed with a biopsy, which includes histological and cytological analysis of a small area of cancer tissue. In such cases, marker diagnostics can determine the initial focus of malignant cell degeneration.
- Prognosis for some cancers
Within the same body, different types of oncology can progress and spread differently. Sometimes, by the level of a specific marker, a doctor can determine the sensitivity of cancer tissues to treatment procedures, evaluate the aggressiveness of tumor growth and the prospects for postoperative survival rate.
- Presence of repeated cancers
Tumor markers are also used to diagnose possible relapses of cancer. This procedure is carried out during preventive examinations of patients in the postoperative period.
Disadvantages of marker diagnostics
How to identify cancerat an early stage of the disease? To date, there are literally several types of markers that allow one to suspect cancer at the beginning of their development. There are several reasons for this condition:
- Almost every person has a small number of such markers in the blood, which greatly complicates the diagnostic process.
- The level of the oncologic marker, as a rule, increases when the size of the malignant neoplasm is reached.
- In some people, blood counts do not change during a cancer injury.
- Even in the case of a significant increase in blood marker values, this is not yet an absolute evidence of the presence of neoplasm.
- The impossibility of using a single marker for the diagnosis of several cancers.
Specific tumor markers
Tumor markers are of two types:
- Markers that are localized in blood and urine.
- Markers found in the tissues of a cancerous tumor.
In the laboratory, basically, all levels of diagnostic substances are analyzed.
Alpha-fetoprotein helps in the diagnosis and management of liver damage to the liver. Normal levels of AFP are at the level of 10 ng / ml. A slight increase in this indicator indicates a possible hepatitis, and a marker value of more than 100 units indicates liver cancer.
Beta-2-microglobulin is used in the diagnosis of myeloma, chronic lymphocytic leukemia and some types of lymphomas. Normal values, as a rule, do not exceed, mg / l.
BTA antigen is found in the urine of patients with cancer of the bladder. This testing is not often used, because cytological diagnosis in bladder cancer is much more reliable.
CA 15-3 - blood shows breast cancer. A high level of the marker in the early stages is noted in 10% of patients, and in approximately 70% of patients an increase in marker indicators is observed in the late stages of oncology.
Calcitonin is a hormone produced by the cells of the thyroid gland and taking part in the regulation of calcium metabolism in the body. Normal levels of calcitonin are in the range of 5-12 pg / ml.
This is one of the rare markers of oncology, which is used in the early diagnosis of thyroid cancer. Measurement of the level of calcium in the circulatory system is considered a key moment in determining the initial stage of the genesis of the genetic mutation of parafollicular cells..