The way to diagnose the prostate cancer with oncology with the help of the PSA definition is not very accurate, that is, according to its results it can not be said that cancer is detected or vice versa. The test allows specialists to determine whether there is a need for a more thorough examination of the patient.
The method does not create discomfort, absolutely painless. This advantage allows it to be applied once a year or as often as necessary.
What is PSA?
Prostate produces the substance needed to dilute the sperm. Some of it gets into the blood.
The amount of antigen in the blood changes from the state of health of the man, age, loads. Experts have studied this pattern and use the PSA indicators as a diagnostic tool.
The method is a conventional blood sampling from a vein. Two milliliters is enough to conduct the test. The time for obtaining the analysis data does not exceed two days.
For the veracity of the result, it is necessary to prepare for the procedure and carry out a number of restrictions related to loads, diet and combination with other manipulations.
When is a blood test done?
If a patient is diagnosed with a malignant prostate tumor, a blood test showing the level of PSA is needed to observe how the body responds to treatment procedures.
A decrease in the antigen level will indicate that the procedures performed are effective. If there are no changes in the value of PSA, then specialists can change the tactics of treatment.
Blood test for PSA is not an accurate indication of the level of the problem. The suspicions that arise in connection with the value of PSA and its change is only an indicator that it is necessary to apply other methods to clarify the diagnosis.
Prostate cancer also occurs with the antigen present at normal levels. A deviation from the norm is also found in the case of a benign tumor or inflammatory processes in the prostate.
How much of the prostate-specific antigen in the blood should be in the patient so that one can talk about the normal content of this substance - the answer to this question is ambiguous.
The presence of PSA increases with age - this is a natural process.
- In the age of up to fifty years, the norm is 2.5 ng / ml.
- If the patient is older than fifty and before the beginning of the sixth dozen, the norm is 3.5 ng / ml.
- During the seventh decade, 4.5 ng / mg is considered normal.
- At a lifetime after seventy years, a normal value of 6.5 ng / mg is considered.
Prostate increases in size with age, this may affect the amount of PSA produced. To take into account this factor, the specialists introduced the concept that this phenomenon translates into a specific indicator - the PSA density.
It is determined by dividing the values of prostate-specific antigen in serum by the volume of the organ that produces it. If the density does not exceed 0.15 ng / mg per cubic centimeter, then it is considered normal.
PSA in the blood is present in two forms:
- antigens are free,
- too, but associated with blood proteins.
The sum of the antigens present in the blood in different forms is called the total PSA.When considering the PSA index, the percentage of free PSA content in the total number of antigens is analyzed. For the norm this indicator should be more than 15%.
Due to the fact that the level of PSA in the blood increases with age, and also it grows with oncology of the prostate and its other diseases, it is necessary to observe the changes of the indicator in time.
Therefore, specialists introduced the concept of PSA speed. It is determined by comparing the results of the PSA test at a certain interval.
The value of PSA in prostate cancer
Pathological cells also secrete PSA, and this increases its presence in the body.
The indicator value corresponding to the age group is considered normal. And if the level of PSA is higher than this, then we can assume the development of an oncological process.
The antigen level is above four and up to ten nanograms is called the gray zone. This is due to the fact that the patient does not have a malignant prostate tumor, but in a quarter of cases the process has an early stage and proceeds in a latent form.
If the pathology ripens to a late stage, then the value of PSA in the blood test will be above 10 ng / mg.
In prostate cancer, the ratio of PSA in bound and free form changes. The amount of free antigen is reduced. Its presence in the total quantitative value of PSA is less than ten percent occurs in half of patients suffering from prostate cancer.
In malignant gland pathology, the rate of increase in PSA is greater than 0.75 ng / mg over the year. This factor indicates cancer, even if the antigen level in the blood does not exceed 4 ng / mg.
Level after radical prostatectomy
Because the prostate-specific antigen produces prostate cells, after an operation to remove it, the PSA test, with a favorable postoperative period, should show a minimum amount of antigen in the blood - 0.2 ng / mg and below this reading.
If the PSA test shows a value greater than what should be in the absence of the prostate, especially if there is a tendency to increase it, then this analysis signals that the body is experiencing recurrence.
After Radiation Therapy
When a method of irradiating a malignant tissue is used, the effectiveness of the procedure can be checked by performing an analysis on PSA.The indicator does not fall as fast as when the prostate is removed.
What can affect the result?
The increase in PSA levels may be influenced by temporary causes that should be taken into account when passing the analysis in order to obtain a true result.
- 48 hours before blood donation:
- not to be eaten:
- fried food,
- spicy dishes,
- large amount of fat, especially of animal origin;
- to abandon sexual intimacy;
- not to be eaten:
- analysis on an empty stomach.
- If prostate manipulation was performed:
- massage or biopsy, the analysis should be postponed for half a month;
- during a finger examination, prostate TRUS, bladder catheterization, colonoscopy - blood sampling for PSA is postponed for a week.
- One day before the procedure, it is necessary to limit physical activity:
- to abandon cycling,
- to shorten the duration of pedestrian walks.
A video about when the PSA score increases: