Can Prostate Cancer Be Detected Early?

Screening for prostate cancer in the community can help some types of cancer to be found at an early stage where it will be easier to treat. Prostate cancer can usually be detected early by testing the levels of prostate specific antigen (PSA) in the blood. Another way to find prostate cancer is with a palpable digital rectal examination (PRM) of the prostate. If the results of any of these tests are abnormal, further testing and a prostate biopsy can usually be done to see if cancer is present.

All these result in the necessity to divide prostate cancer into two groups as clinically significant and insignificant cancers. In fact, most of the studies have focused on making this distinction. Thus, it is tried to reduce the diagnosis of clinically insignificant cancer and to avoid unnecessary biopsies. As a result, excessive treatments such as urinary incontinence, impotence and hormone use that reduce the quality of life are avoided. Sometimes, patients diagnosed as clinically insignificant may decide to have active monitoring without any treatment, even the examinations performed during the follow-up and the biopsies that need to be performed repeatedly create stress on the patient, and they are forced to be exposed to the side effects of biopsies such as infection and bleeding.

Screening Tests for Prostate Cancer

Screening is tests to detect prostate cancer in people before they have symptoms. However, it is unclear whether the benefits of community screening for prostate cancer outweigh the risks. However, after discussing the pros and cons of screening, some people may be screened.

PSA

Prostate specific antigen (PSA) blood test: Prostate-specific antigen (PSA) is a protein made by cells in the prostate (both normal cells and cancer cells). PSA is found in large amounts (one million times) in semen, it is an enzyme that keeps the semen watered in the external environment, and a small amount passes in the blood. The level of PSA in the blood is measured in units of nanograms per milliliter (ng/mL). The higher the PSA level, the higher the chance of developing prostate cancer, but there is no definite cut-off point that can definitively tell if prostate cancer is present. He often uses a PSA cut-off point of 4 ng/mL or higher, but may generally recommend starting at a lower level such as 2.5 or 3 ng/mL.

Most men without prostate cancer have PSA levels below 4 ng/mL. When prostate cancer develops, the PSA level usually rises above 4. Still, a level below 4 is not a guarantee that a man does not have cancer. About 15% of men with PSA levels below 4ng/mL can detect prostate cancer if a biopsy is performed. The range of PSA, 4-10 ng/nl is called the gray-zone or borderline range, and the approximate prostate cancer risk is 25% in this range. If the PSA is higher than 10, the chance of getting prostate cancer is over 50%.

Factors that can affect PSA levels:One reason why it is difficult to use a specific cutoff point with PSA testing when searching for prostate cancer is that many factors other than cancer can also affect PSA levels.

Factors that can raise PSA levels include:

  • 1- Prostate enlargement: Benign prostatic enlargement (BPH) can raise PSA levels in non-cancerous prostate enlargement that affects many men as they age.

  • 2-advanced age: PSA levels normally rise gradually as you get older, even if you don’t have a prostate problem.

  • 3- Prostatitis: Prostate infection is an important clinical condition that can increase PSA levels, such that it can increase much more in acute infections.

  • 4- Semen Ejaculation: It can cause PSA to rise for a short time. It is therefore recommended to avoid semen ejaculation for a day or two prior to the test.

  • 5- Cycling: Although some studies claim that cycling can raise PSA levels for a short time, this has not been proven.

  • 6- Some urological interventions: Some procedures that affect the prostate, such as prostate biopsy or cystoscopy, can raise PSA levels for a short time. Some studies have suggested that digital rectal examination (DRE) may slightly raise PSA levels, but it has not been proven. As a rule, it is recommended that the PSA test be performed before digital rectal examination.

  • 7- Some drugs: Male hormones such as testosterone and taking these hormones can cause an increase in PSA.

Reasons that lower PSA levels include (even if prostate cancer):

  • 1- Finasteride and Dudaster (5-alpha reductase inhibitors): Some drugs such as finasteride (Proscar) or dutasteride (Avodart), which are used to treat normal prostate enlargement or some urinary complaints, reduce PSA levels by half within 3 months. It is obtained by multiplying by two. These drugs may also affect the risk of prostate cancer and may mask prostate cancer by lowering PSA.

  • 2- Herbal mixtures: Some mixtures sold as dietary supplements may mask high PSA levels. Saw palmetto, used for normal prostate enlargement, does not seem to affect PSA much.

  • 3- Some other drugs: Some studies have suggested that long-term use of certain drugs such as aspirin, statins (cholesterol-lowering drugs), and thiazide diuretics (such as hydrochlorothiazide) may lower PSA levels.

Special PSA types: PSA is sometimes referred to as total PSA because it includes different forms of PSA. If the PSA screening test result is not normal, he or she may sometimes consider different PSA tests to help you decide whether you need a prostate biopsy.

These special PSA derivatives are:

Percentage of free PSA: PSA occurs in the blood in 2 main forms. One form binds to blood proteins, while the other circulates free (unbound). The percent free PSA (% fPSA) indicates what percentage of the total PSA free PSA makes up. The percentage of free PSA is lower in men with prostate cancer than in men without. Normally, it is expected to be above 25%, it guides us in making a biopsy decision, especially in patients with blood total PSA levels in the range of 4-10 ng/mL (gray zone). Low free PSA and high total PSA levels are a finding that increases the probability of prostate cancer and is a factor that influences our decision to biopsy.

Complex-Complex PSA: This test directly measures the amount of PSA (the “non-free” part of PSA) that binds to other proteins. This test can be used in place of total and free PSA and can give us the same value of information, but it is not widely used.

Tests combining different types of PSA:Some newer tests combine the results of different types of PSA to get an overall score that reflects the chance of getting prostate cancer.

  • -Prostate Health Index (PHI), which combines total PSA, free PSA, and proPSA results

  • -4Kscore test combining total PSA, free PSA, intact PSA and human kallikrein 2 (hK2) results with some other factors

These tests may be useful in patients with a mildly elevated PSA to help determine whether they should have a prostate biopsy. These tests can also be used to determine if a patient who has had a prostate biopsy but no cancer is found should have another biopsy.

PSA rate: The PSA rate is no different test. It is a measure of how quickly the PSA rises over time. Normally, PSA levels gradually rise with age. It has been found that it increases more rapidly in prostate cancer patients. Although it is not used much, an increase of more than 0.74ng/mL/year per year can be considered significant.

PSA density(PSAD): The volume (size) of the prostate gland is measured by transrectal ultrasound and the PSA level is divided by the prostate volume, that is, the amount of PSA per gram of tissue gives the PSA density. Normal value is expected to be below 0.15, biopsy can be considered with a value above 0.15.

Age-specific PSA ranges: Blood PSA levels are normally higher in older men than younger men. A PSA value in the upper range of normal may be worrisome for a 50-year-old man, but is less of a concern for an 80-year-old. Some age-specific PSA levels have been described, but it is not a widely used test.

Finger Rectal Examination (PRM)

In Digital Rectal Examination, while it is felt very hard with a focus that may be cancer in the prostate, normal prostate tissue has the consistency of a rubber ball. It is unlikely to be diagnosed on its own.

Prostate Cancer Screening Criteria

  • 1- Age 50 for men at average risk of prostate cancer and expected to live at least 10 more years. Age 45 for people at high risk of developing prostate cancer. Among the risky people; Those with a first-degree relative (father or brother) diagnosed with prostate cancer younger than age 65 and being black count. For men at higher risk, 40 is the age limit, and those with more than one first-degree relative with prostate cancer at an early age are in this group. People with these criteria can be screened by performing PSA and digital rectal examination.

  • 2- Having a BRCA gene mutation and/or being of African origin are included in the group with a high risk of developing prostate cancer.

  • 3- If the PSA value is less than 2.5 ng/mL in patients who are included in the screening criteria, a PSA test should be repeated every 2 years, and for men with a PSA level of 2.5 ng/mL or higher, a PSA test should be repeated annually.

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