PSA AS A METHOD FOR DIAGNOSIS OF PROSTATE CANCER

Prostate cancer is one of the most common cancers worldwide. In Europe and America, prostate cancer is the second leading cause of death from malignant diseases. In Russia, there is a growing trend in the number of patients newly diagnosed with prostate cancer: over the past 10 years, the incidence of prostate cancer per 100 thousand population has increased by 120.5%1.

The main danger is that this disease develops very slowly, the time from the appearance of the first cancer cells to the detection of symptoms is tens of years.

What is PSA

At the beginning of the 21st century, prostate-specific antigen (PSA) was discovered in hyperplasia and cancer in the epithelium of the prostate and periurethral glands, which is currently the most important marker in the diagnosis and treatment of prostate cancer2.

PSA is a protein that is constantly produced in the prostate to liquefy seminal fluid. An increase in PSA levels indicates damage to the capillaries of the prostate gland, which may indicate the presence of a malignant tumor in the body. Elevated PSA levels may also indicate prostatitis, adenoma (benign prostatic hyperplasia) and some other diseases. The probability of cure in the first stages of detection is 95–97%, which is why it is so important to be examined in time to reduce the risks of further development of the disease.

Tumor marker CA 125

The main marker of ovarian cancer and its metastases. Normally, the concentration of tumor marker in the blood is 0-30 IU/ml. Elevated CA 125 levels, more than 30 IU/ml, may indicate malignant diseases:

ovaries (mainly),

uterus (inner layer - endometrium),

mammary gland.

pancreas (in combination with CA 19-9)

Preparation:

Fasting is when at least 8 hours (preferably at least 12 hours) pass between the last meal and the blood draw.

Physiologically, an increase is observed during pregnancy and during menstruation.

What does a PSA test show?

A PSA blood test is prescribed to the patient by a urologist, oncologist or therapist if he has symptoms of prostate pathologies, as well as when visually detecting (ultrasound or MRI) the presence of a tumor in the groin area. In addition, the study is mandatory for all patients who are at the stage of cancer therapy or are being observed after surgical treatment. PSA testing is used to:

1. initial examination to identify pathologies of the prostate gland - cancer, prostatitis, inflammatory infections, ischemia or heart attack;
2. differential diagnosis of benign and malignant neoplasms;
3. determining the effectiveness of the chosen treatment tactics for prostate cancer;
4. early detection of disease relapse;
5. monitoring the effectiveness of surgical tumor removal;
6. early detection of foci of metastasis;
7. large-scale preventive screening of the patient in order to exclude diseases.

Tumor marker CA 15-3 (Mucin-like glycoprotein)

or breast tumor marker. An indicator of the course of the disease and the effectiveness of therapy for breast carcinoma. Normally, the level of CA 15-3 is 0-22 U/ml. Tumor marker CA 15-3 is effective in determining relapses. Some elevation of the marker may also occur during pregnancy.

Increased SA level 15-3

Breast carcinoma (a particularly high level is observed in late stages and in the presence of metastases),

Bronchogenic carcinoma,

Stomach cancer,

Liver cancer,

Pancreas cancer,

Cancer of the ovaries, endometrium, uterus (late stages of tumor development).

When should you think about getting a PSA test?

Doctors in different countries disagree about the optimal age for taking this test. In the United States, they believe that before a PSA test you should consult a doctor, weigh all the risks and benefits, and only make a decision after consultation.

In Russia, the most common point of view is that it is recommended to undergo research after 40–45 years of age without special medical indications. However, if one of your close relatives has had a malignant tumor of the prostate gland, the risk of getting sick increases 10 times, and getting tested after 40 years is necessary. Symptoms that might make you consider getting a PSA test are related to any urinary problems, such as pain or burning, frequent urination at night, or blood in the urine or semen.

“Only 12 percent know what prostate-specific antigen (PSA) is, the most important test for detecting prostate cancer. Only one and a half percent of men ask their doctor to perform this test for them. But it is no coincidence that it is included in the list of mandatory medical examinations: every man after 45-50 years of age should know his PSA number. If it is more than 4.0, then a biopsy is necessary because the risk of prostate cancer is high. The doctor prescribed this test - you need to go and take it. If you didn’t appoint it, this happens; you have to demand a referral yourself,” said Dmitry Yuryevich Pushkar, Academician of the Russian Academy of Sciences, professor, Honored Doctor of the Russian Federation, chief urologist of the Ministry of Health of the Russian Federation, head of the Department of Urology at Moscow State Medical University named after. A.I. Evdokimov.

Preparing for a PSA blood test

You can donate blood for PSA in almost any laboratory, but you should prepare in advance. In order for the PSA test to be reliable, a number of rules must be followed before taking the test4:

1. Tell your doctor if you are taking finasteride (Proscar, Penester, Finast), dutasteride (Avodart) or other drugs that lower PSA levels or may affect the test result;
2. Examinations should not be carried out against the background of acute inflammatory diseases of the genitourinary system.
3. More than a month should pass after the biopsy (if one was performed).

Two weeks before the study, the following procedures should not be performed:

1. Prostate massage, digital rectal examination and any other mechanical effects on the prostate;
2. Transrectal ultrasound;
3. Cytoscopy or catheterization of the bladder.

4-5 days before the test you should refrain from sexual activity and heavy physical activity. The day before the test, it is not recommended to consume a lot of fatty foods, tea, coffee, and avoid alcohol. A few hours before the test, it is best not to expose the body to emotional stress. A PSA blood test is taken from a vein on an empty stomach.

Decoding the PSA analysis

This antigen is present in certain quantities in the blood of every man and changes with age. Thus, among men aged from forty to fifty years, the upper limit of this value is set at up to 2.5 ng/mm, after fifty years PSA has a limit value of 3.5 ng/mm, and in older men – up to 4.5 ng/mm. The maximum permissible PSA value of up to 6.5 ng/mm can be observed in men after seventy years of age. These data are approximate and depend on the characteristics of the body of each individual man. However, when the antigen content is greater than 10 ng/mm, the likelihood of a malignant tumor increases significantly. In addition to prostate cancer, causes of increased PSA may also include3:

1. The presence of inflammation or infection in the prostate;
2. Benign prostatic hyperplasia (prostate adenoma);
3. Ischemia or infarction of the prostate;
4. Ejaculation on the eve of the study.

PSA blood test table by age

After removal of the prostate, the antigen in the blood should not exceed 0.2 ng/ml, however, in the case of radiation therapy without prostatectomy, the levels decrease more slowly, sometimes taking more than a year. In most cases, the patient can go 3-5 years without fear of relapse if PSA drops below 1 ng/ml after undergoing radiation therapy.

Prostate tumor marker

Prostate cancer develops from the glandular tissue of the prostate. Its frequency increases among men over forty years of age.

After fifty years of age, prostate cancer is diagnosed in every seventh man.

Prostate tumor marker is a specific protein, the level of which can be used to judge the condition of the prostate gland.

Causes and symptoms of prostate cancer

The prostate gland or prostate is an organ shaped like a chestnut. It covers the initial part of the urethra.

The main function of the gland is the synthesis of seminal fluid and participation in the act of ejaculation. The prostate also affects a man's ability to hold urine.

There are many theories about the origin of prostate cancer.

An important role in the pathogenesis of the disease is played by the male sex hormone testosterone, which is produced by the testicles.

The likelihood of developing prostate cancer and the level of tumor malignancy directly depend on the concentration of this hormone in a man’s blood.

Prostate cancer develops under the influence of the following risk factors:

• elderly;
• family history (close relatives of the patient had prostate cancer);
• existing progressive prostate adenoma;
• bad environment;
• work with cadmium (printing and welding work, rubber production);
• poor diet (eating too much animal fat and not enough fiber).

What happens to the gland?

Prostate cancer has a slow but malignant course. The tumor grows over a long period of time. From the moment of metaplasia of the glandular epithelium and the appearance of a microscopic tumor in the prostate until the development of the last stage of cancer, ten or fifteen years pass.

However, prostate cancer is prone to early metastasis. Cancer cells spread throughout the body through lymphatic vessels.

Metastases are found in the lymph nodes, bones of the pelvis, hips, spine, lungs, liver and adrenal glands. Tumor markers will be elevated.

In most cases, prostate cancer is asymptomatic at the beginning of the disease. Patients are concerned about pain in the perineum, frequent urination, and dysuric disorders. But the same phenomena also occur with prostate adenoma, so most men do not pay any attention to this.

The appearance of blood in the urine is alarming.

The use of tumor markers for these symptoms is quite justified.

Further, men of reproductive age note problems with ejaculation and the phenomenon of erectile dysfunction.

In the future, chronic or acute urinary retention occurs, and symptoms of cancer intoxication are added: causeless weakness, increased fatigue, weight loss, pallor.

The skin takes on an earthy tint. Determining the concentration of a tumor marker helps in diagnosing the disease.

Methods for diagnosing prostate cancer

Today, doctors have many methods in their arsenal to make the correct diagnosis of prostate cancer in the early stages of the tumor process.

• First, the doctor examines the prostate gland through the rectum.

Digital rectal examination of the prostate can detect enlargement of the prostate. If you have prostate cancer, the prostate will be firm and lumpy.

The gland is painful on palpation.

Such symptoms indicate that we are dealing with advanced prostate cancer.

Therefore, even if the doctor does not find a tumor-like formation in the prostate, he must write out a referral for a tumor marker.

PSA is an organ-specific tumor marker.

The following instrumental research methods are also used to diagnose prostate cancer:

• transrectal ultrasonography (ultrasound examination of the prostate using a rectal sensor);
• CT scan;
• radiography of bones and scanning them using a radioactive isotope.

Today, the tumor marker prostate-specific antigen (PSA) is used for early diagnosis of prostate cancer.

It is the most effective tumor marker for prostate cancer.

Testing for prostate specific antigen levels can detect prostate cancer.

• Its limit value is 4 ng/ml.
• If a man has an increase in PSA to 10 ng/ml, then the probability of prostate cancer in this patient reaches twenty-five percent.
• If the PSA concentration is 10 ng/ml or higher, then the likelihood of prostate cancer increases to seventy-five percent.

Non-invasive methods of serological diagnosis involve the calculation of several PSA indicators:

1. Its density: in the absence of nodular neoplasms, the level of total PSA is within twenty nanograms per milliliter and the density is in the range from 0.13 to 0.15 ng/ml per 1 cm. This indicates that the tumor is benign.
2. The rate of increase in PSA levels: the concentration of total PSA should not increase by more than 0.751.36 ng/ml per year.
3. Proportion of free and total PSA: The proportion of bound PSA increases significantly and the proportion of free PSA decreases significantly in patients with prostate cancer.

Today, urologists recommend that all men after fifty years of age undergo an annual rectal examination and determine the level of the PSA tumor marker.

If a man is at risk of prostate cancer (his blood relatives had prostate cancer), then he is recommended to be screened with a tumor marker after forty years.

If the study determines that the PSA level is less than one microgram per liter, then the next test can be taken at the age of forty-five.

If the concentration of the PSA tumor marker is in the range from one to two and a half micrograms per liter, then you should be examined annually.

If the analysis reveals a PSA level greater than or equal to 2.5 mcg/l, then the man should undergo further research, including a biopsy of the gland tissue.

An increased concentration of a prostate-specific tumor marker in the blood does not mean that it is a completely malignant tumor. The fact is that PSA levels also increase with prostate adenoma.

In order to differentiate between malignant and benign prostate tumors, the proportion of free PSA is determined for patients whose PSA tumor marker is in the range from 4 to 10 μg/l.

This significantly increases the specificity of the test for prostate cancer.

Typically, the normal limit for the ratio of free and total PSA is fifteen percent.

How to prepare for a PSA test?

Each patient must realize that the correctness of the indicators, and therefore the accuracy of the diagnosis, depends on preparation.

Therefore, patients who are preparing to study the PSA tumor marker should adhere to the following rules:

• refrain from ejaculating for at least two days before taking the test.
• the study can be carried out no earlier than three days after prostate massage;
• The level of the PSA tumor marker can be examined six months after transurethral resection;
• PSA tumor marker analysis can be performed seven days after TRUS;
• the interval between prostate biopsy and PSA test should be less than six weeks.

For examination, blood is taken from the cubital vein.

The test is taken on an empty stomach, and on the eve of the test, the patient is advised to refrain from drinking alcoholic beverages, fatty, spicy and fried foods.

It is better to donate blood in the morning.

Before donating blood, the patient must be provided with complete physical and psychological rest.

He should also refrain from smoking for two hours.

If you are faced with the problem of prostate cancer, consult a urologist.

You will need to undergo a comprehensive examination, which includes determining the level of the PSA tumor marker.

If cancer is confirmed, early treatment is a guarantee of successful treatment of the disease.

This article is for informational purposes only. A urologist at our Clinic can tell you in more detail about the prevention of diabetes.

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Free PSA

It is also important to monitor free PSA levels. Free PSA is the free fraction of PSA that is not bound to α1-antichymotrypsin or other binding proteins. A free PSA level of 12-100% may indicate the presence of a tumor process or its relapse. It should be noted that the value of free PSA in patients with a malignant tumor will be lower than in patients with a benign one. For reliable interpretation of the results, the following ratio is calculated: PSA-free / PSA-total x 100%. The results are interpreted as follows:

1. 15–100% – favorable prognosis,
2. less than 15% – unfavorable prognosis.

You should not take into account the indicators of this ratio if the volume of the prostate gland is more than 40 - 60 cm3. In this situation, it is possible that hyperplastic prostate tissue may influence increased excretion of PSA into the bloodstream, which can lead to normal levels of free PSA in patients with a malignant tumor or prostate adenoma.

Tumor marker CA 19-9

tumor marker of the pancreas, gall bladder, marker of pancreatic carcinoma. A blood concentration of 40 IU/ml or higher is considered pathological. Elevated levels of this marker are a poor prognostic sign in patients with colon and rectal cancer.

Increased CA level 19-9:

Pancreas cancer,

Stomach cancer,

Colon cancer,

Rectal cancer

Gallbladder cancer

Determining the likelihood of prostate cancer

After determining the total PSA (tPSA) and the percentage of free PSA (%fPSA), you can determine the probability of having prostate cancer (PCa) in accordance with table 5.

Please note that interpretation of PSA test results (total and free, index, probability of cancer) in men is carried out only by specialists.

How to lower PSA?

PSA is a good way to diagnose prostate-related diseases in the early stages. But every person has the opportunity to reduce PSA, and therefore the likelihood of developing a malignant tumor. The following steps will help:

1. rejection of bad habits,
2. maintaining a healthy lifestyle,
3. optimal physical activity,
4. special diet - it is recommended to add more Omega-3 polyunsaturated fatty acids, which are found in fatty fish, to the diet, it is better to replace black tea with green tea, and instead of sunflower oil, use olive, flaxseed or rapeseed oil. It is also recommended to limit the intake of fermented milk products. You should diversify your diet with fresh fruits and vegetables.