womensecr.com
  • Algorithm for research of oncomarkers

    Specificity of tumor markers - the percentage of healthy individuals and patients with benign neoplasms, in which the test gives a negative result.

    Cancer sensitivity is the percentage of results that are truly positive in the presence of a given tumor.

    Threshold concentration( separation point) is the upper limit of oncomarker concentration in healthy individuals and patients with non-malignant neoplasms.

    Factors affecting in vitro for the concentration of oncomarkers in the blood

    ■ Conditions for storage of blood serum( should be stored in the cold).

    ■ Time between sampling and centrifugation( no more than 1 hour).

    ■ Hemolysed blood serum( NCE concentration increases).

    ■ Sample contamination( increased concentration of CEA and CA 19-9).

    ■ Acceptance of drugs( increase the concentration of PSA ascorbic acid, estradiol, ions of 2- and 3-valent metals, guanidine analogs, nitrates, etc.).

    Factors affecting in vivo on the concentration of oncomarkers in the blood

    ■ Produce tumor oncocomarker.

    ■ Isolation of an oncomarker into the blood.

    ■ Tumor weight.

    ■ Blood supply to the tumor.

    ■ Daily variations( it is necessary to take blood for testing at the same time).

    ■ Body position at the time of blood collection.

    ■ Influence of instrumental studies( X-rays increase the concentration of HCE, colonoscopy, digital rectal examination - PSA, biopsy - AFP).

    ■ Catabolism of the oncomarker( functioning of the kidneys, liver, cholestasis).

    ■ Alcoholism, smoking.

    Objectives for the determination of oncomarkers in clinical practice

    ■ An additional method for the diagnosis of cancer in combination with other research methods.

    ■ Management of oncological patients - monitoring of therapy and monitoring of the course of the disease, identification of tumor remains, multiple tumors and metastases( the concentration of oncomarker can be increased after treatment due to tumor disintegration, therefore, the study should be conducted 14-21 days after the start of treatment).

    ■ Early detection of tumor and metastases( screening in at-risk groups - PSA and AFP);

    ■ Definition of disease prognosis.

    Scheme of appointment of research of oncomarkers

    1. To determine the level of oncomarker before treatment and further to study those oncomarkers that have been raised.

    2. After the course of treatment( operation), examine after 2-10 days( corresponding to the half-life of the marker) in order to establish an initial level for further monitoring.

    3. To assess the effectiveness of treatment( operation) to conduct a study after 1 month.

    4. Further study of the level of oncomarker in the blood should be carried out once a month during the 1st year after treatment, once in 2 months during the 2nd year after treatment, once every 3 months for 3-5 years( recommendationsWHO).

    5. Conduct an oncomarker study before any treatment change.

    6. To determine the level of oncomarker in case of suspected relapse and metastases.

    7. To determine the level of the oncomarker after 3-4 weeks after the first detection of its increase.

    The scheme of rational use of oncomarkers for diagnosis of oncological diseases is given in Table. .

    Table Definition of tumor markers

    Table Definition of tumor markers