Prostate cancer is one of the most common types of cancer that progresses quite insidiously.
The prostate is an important part of the male reproductive system and is a walnut-sized gland that sits below the bladder and in front of the rectum. The urinary canal called the urethra passes through the center of this gland. The prostate gland contributes 1/3 of the semen secreted in men. A normal prostate weighs around 20 grams. An increase in the prostate size does not necessarily mean there is cancer in the prostate.
Prostate cancer usually involves malignant tumors that start in the outer layer of the prostate and metastasize All the tissue cells of the body renew themselves within a certain control mechanism. Thus, any damaged tissue is repaired and regenerated. Cells that get out of control and multiply unnecessarily form cell groups called tumors.
Prostate tumors, which stay in their site and do not metastasize to other organs, are called benign (benign) tumors. Prostate tumors, which metastasize to neighboring organs, are called malignant tumors. Malignant tumors in the prostate are called prostate cancer.
Prostate cancer is the most common type of cancer in men. It is found in one out of every nine men worldwide. The average age of a prostate cancer diagnosis is 66.
What are the Symptoms of Prostate Cancer?
Prostate cancer usually shows no symptoms in the early stages. However, there are some symptoms known to indicate cancer in the prostate:
- Erectile dysfunction
- Discomfort in the groin area
- Painful ejaculation
- Blood in the semen or urine
- Weaker urine flow
- Bone pains (in metastatic diseases)
- Difficulty in urination
Causes and Risk Factors of Prostate Cancer
The exact causes of cancer development in the prostate tissue are unknown. However, some risk factors have been revealed to be associated with cancer.
Age: Cancer is very rare in men younger than 40 years of age. When a man turns 50, he becomes more likely to develop cancer. 2 in 3 patients diagnosed with cancer are men over 65 years of age Prostate cancer in men younger than 60 usually has a more aggressive course.
Race: The disease is more common in Afro-American (black) men than in men of other races. It is less common in Asian and Latino men. The causes of these racial and ethnic differences are not clear.
Geography Prostate cancer is more common in North America and Northwest Europe, while is less common in Asia, Africa, Central and South America. The cause of this is not clear.
Family history: The disease has been found to develop in all generations of some families. Men who have close family members (grandfather, uncle, father or brother) diagnosed with cancer (especially before 55 years of age) are more likely to develop cancer.
If a family member has cancer, other individuals are 2 times more likely to develop cancer. If two or more family members have cancer, this risk increases by 6 to 11 times.
Genetic Features: Some gene disorders were found in one out of every 5 men with prostate cancer, who had no family history of cancer. Especially the BRCA-2 gene disorder revealed to be associated with breast cancer has also been proven to be associated with prostate cancer. Men with a disorder in their BRCA-2 gene are more likely to develop cancer.
Diet: It is not clear whether diet plays a certain role in this type of cancer. Prostate cancer is more common in men who eat a diet rich in protein.
A red meat-based diet or a diet rich in fat has not been shown to be associated with prostate cancer (published in 2020). It is less common in men who eat a diet rich in phytoestrogens (soybeans, soy milk, flaxseed, whole wheat grains, spinach, cabbage, strawberries, apples, raisins).
The mortality rate from prostate cancer is higher in those who consume too much alcohol.
Prostate cancer is more common in men with lower levels of vitamin D. No relationship has been revealed between the use of vitamin E and prostate cancer. If prostate cancer develops in men with selenium deficiency, the disease demonstrates a more aggressive course.
Male-pattern baldness: Bald men are at a higher risk of dying from prostate cancer.
Gonorrhea (gonorrhea infection): Men who have had gonorrhea infections are more likely to develop cancer.
Smokers: Heavy smokers are at a higher risk of dying from cancer.
Men working in a cadmium-related work: Cancer is more common in men working in certain industries that cause exposure to electricity, ceramics, battery and accumulator.
Men who ejaculate less: Prostate cancer is 25% more common in men who ejaculate 2 times a week or less frequently than men who ejaculate 4 times a week.
Diagnosis of Prostate Cancer
In order to be able to treat prostate cancer, it is necessary to diagnose it early when it is still confined to the prostate gland, i.e., before it metastasizes to any part of the body.
Today, no blood test, genetic test, or imaging method (ultrasound, MRI, PET) can definitively detect cancer cells confined to the prostate in a man. Therefore, every man over 50 years of age who applies to a urologist is considered to be a potential prostate cancer patient, and some tests are performed accordingly.
Prostate biopsy is recommended for men considered to be at risk for cancer.
Diagnostic and Test Procedures
Whether a prostate biopsy is needed is determined based on the results of the examinations and tests. The examinations and tests performed are as follows:
Digital Rectal Examination (DRE): The physician wearing gloves puts his finger into the patient's anus. He examines the size and shape of the prostate by using his finger. If he feels a hardness inside the prostate, he suspects cancer and recommends a prostate biopsy to the patient.
The hardness, which is rarely felt by the finger during examination, may be due to a prostate stone or granulomatous inflammation of the prostate.
A- Blood Tests:
PSA (Prostate-Specific Antigen): It is based on the measurement of a protein produced in the prostate gland, which can be detected in the blood. Conditions such as cancer, infection and benign prostate enlargement (BPH) increase the blood PSA levels A PSA test does not make a definitive diagnosis of cancer, but shows the risk of cancer.
PSA levels are within normal limits in one out of every 4 prostate cancer patients. A prostate biopsy should definitely be performed for patients with a PSA value above 10. There are a variety of PSA forms such as total PSA, free PSA, and pro-PSA.
If the patient is examined for prostate cancer only with PSA and a digital (finger) rectal exam; 25% of cancer cases cannot be detected. With some additional tests, 95% of cancer cases are detected.
Prostate Health Index and 4K test: These are tests produced from the inferior segment of PSA, which determine the risk of prostate cancer much better than PSA. Blood drawn from the arm is used in both tests. Prostate Health Index and 4K test have similar effectiveness.
B- Genetic-Based Urinary Tests:
Prostate cancer gene 3 (PCA3): It is a test based on PCA3 microRNA analysis of the urine taken after a prostate massage. If a person with a high PSA test result tests negative after PCA3, there is a 91% chance that the person does not have cancer.
Select MDx: It is a test based on HOXC6 and DLX1 microRNA analyses of the urine taken after prostate massage.
Mi Prostate Score: 50% of patients with prostate cancer are found to have TMPRSS2-ERG gene fusion. If a TMPRSS2-ERG gene fusion is observed in the urine taken after the prostate massage, a special calculation is made using the PCA3 and PSA values obtained from the blood. The result is called the Mi Prostate Score.
EcoDx: It is a test performed on the urine to examine exosomes released from prostate cancer cells. Patients who test positive after the EkoDx test are more likely to develop aggressive cancer.
Multiparametric Prostate MRI: It is an imaging test that should be performed using 3 Tesla MRI devices.
The prostate is scanned in detail through a multiparametric MRI. Based on the probability of cancer, suspicious areas in the prostate are graded from 1 to 5 using the PI-RADS system. A biopsy procedure should be performed for patients whose scores are 4 and 5.
Transrectal Ultrasound (TRUS)-Guided Prostate Biopsy: These are old-style biopsy techniques that used to be used before the invention of multiparametric MRI devices. During this procedure, the physician inserts an instrument into the rectum. The instrument produces sound waves (ultrasound), reflecting the image of the prostate. The reflected sound waves monitored on a display give information about the shape, size, and image of the inner parts of the prostate. In this type of biopsy operation, samples are taken from 12 random areas of the prostate gland. These samples are taken by needle biopsy.
MR fusion prostate biopsy: New types of prostate biopsies are performed under the guidance of MRI images. Instead of taking samples from random areas of the prostate gland, a prostate biopsy is performed at points determined during the MRI process. This type of biopsies allows for a 35% more accurate diagnosis.
Aggressiveness Classification in Cancer
If the results of the prostate biopsy indicate cancer, pathologists report the condition. 90% of prostate cancers are a type of cancer developing in the prostate gland, which is called adenocarcinoma. There are a variety of aggressive types of prostate adenocarcinomas.
A classification method called the Gleason rating is used to indicate the aggressiveness of cancer. The most aggressive tumors are classified as 5 and the least aggressive tumors 3 (2020). The 2 most common aggressive types in the prostate are added to yield the Gleason score. The Gleason scores 8, 9, 10 indicate a very aggressive cancer.
In recent years, the International Society of Pathology has begun to use a new classification method called ISUP classification. According to this classification method, the aggressiveness of prostate cancer is classified with a score from 1 to 5. No extra score is assigned to the patient. ‘1’ indicates a low aggressive cancer, while ‘5’ indicates a highly aggressive cancer.
For planning the treatment of a malignant prostate tumor, it is necessary to know the metastasis of cancer, i.e. its stage.
Staging in prostate cancer is a system configured based on the size of the tumor, whether the tumor has spread outside the prostate, and whether it has spread to distant regions. The metastasis (spread) of the cancer cells is determined with some imaging methods.
Magnetic Resonance Imaging (MRI): The internal organs of the body are monitored using a computer connected to a machine that emits strong magnetic waves. There is no radiation in MRI. Especially non-prostatic regional lymph nodes are examined through diffusion-type MRI.
Bone Scintigraphy: A small amount of radioactive material intravenously injected into the body reaches the bones through the blood circulation. A machine measures the amount of radiation stored in the bones and turns the result into an image. In this image, the metastasis of the cancer in the bones is observed. Bone scintigraphy can only show whether the prostate cancer has metastasized to the bones.
Gallium 68 PSMA PET scan: It is an examination method used to investigate the spread of a special substance that binds to prostate cancer cells in the body. The patient receives radiation as a result of this examination. It is the method that best shows which parts of the body cancer has spread to. Today, this test is routinely performed in prostate cancer cases with a Gleason score of 7 or higher before deciding on treatments.
Stages of Prostate Cancer
After the diagnosis of prostate cancer, the stage of the prostate cancer is determined for planning the treatment.
The following system is used to stage prostate cancer:
T1: The growing tumor cannot be felt with palpation or cannot be seen during imaging tests.
- T1a: The tumor was randomly detected during the treatment of benign prostatic enlargement (BPH). The tumor is confined to less than 5% of the tissue taken from the prostate.
- T1b: Cancer cells were found by chance during the BPH operation. Cancer cells exist in more than 5% of the tissue taken from the prostate gland.
- T1c: Cancer cells were detected as a result of the biopsy performed based on the result of the PSA test.
T2: Prostate cancer is confined to the prostate. It can be felt during palpation. It can also be seen during imaging tests.
- T2a: The cancer cells have invaded a part of the prostate gland.
- T2b: Cancer has spread to more than half of the prostate. However, the metastasis is only on one side of the prostate gland.
- T2c: The cancer cells have spread to both sides of the prostate gland.
T3: Prostate cancer has grown beyond the prostate. The cancer cells are likely to have spread to the seminal vesicles.
- T3a: The cancer cells have expanded beyond the borders of the prostate. However, there is no metastasis to the seminal vesicles yet.
- T3b: The cancer cells have metastasized to the seminal vesicles.
T4: Cancer has spread to the seminal vesicles and the tissues next to the prostate gland. The metastasis can be in the rectum, bladder, urethral sphincter, and pelvic wall.
Is Early Diagnosis Possible?
If detected at an early stage (if cancer has yet to spread beyond the prostate), it is possible to get rid of prostate cancer with a suitable and appropriate treatment procedure. For this reason, it is very important for men over 50 years of age to get examined once a year.
Every man over 50 years of age should have a digital (finger) rectal examination and a PSA blood test at least once a year. This makes it possible to detect cancers in the early stages, which have not yet shown any symptoms and do not cause any complaints in the patient.
Black men with a family history of prostate cancer and men who are BRCA2 gene positive should start prostate cancer screening after 45 years of age. Prostate cancer screening tests have decreased the number of men who have died from prostate cancer in the last 20 years.
With the advancing technology and opportunities, effective treatment methods for prostate cancer have been developed and patients have been provided with great conveniences. This cancer is no longer highly lethal and we can take it under control with an efficient treatment process.
Treatment of Prostate Cancer
A variety of treatment options are available for the treatment of prostate cancer. The most suitable treatment procedure for the patient is determined after the doctor's examination and clinical tests.
The treatment procedures commonly preferred for prostate cancer are:
Active Surveillance: The patient is followed up actively with prostate-specific antigen (PSA) and digital rectal examination (DRE) tests, as well as regular prostate biopsies. In the active surveillance method, the development of prostate cancer is regularly checked, and other treatment options are performed only if cancer progresses.
Prostate Cancer Surgery: It is a surgical procedure performed to completely remove prostate cancer from the body. It is called a prostatectomy. In radical prostatectomy, the prostate and the surrounding tissue are removed.
The robotic-assisted surgical procedure performed with the ‘da Vinci’ surgical system to remove cancerous tissues in the prostate is called robotic radical prostatectomy. Robotic prostate cancer surgery provides considerably high success rates and improvements in prostate cancer.
Radiation Therapy: It involves the use of high-energy rays (similar to X-rays) to kill cancer cells. There are two different options for radiation therapy. In external radiation therapy, a machine outside the body directs a beam of radiation to cancer cells. In the internal radiation therapy (brachytherapy) option, radioactive seeds are surgically implanted into or near cancer to destroy the cancer cells.
Other treatment procedures performed in the treatment of prostate cancer, whose clinical research is ongoing, are:
- Cryotherapy: It involves the insertion of a special probe into or near prostate cancer to freeze and kill cancer cells.
- Chemotherapy: It involves the use of special drugs to shrink or kill cancer.
- Biological therapy: It cooperates with your body’s immune system to help it fight cancer or manage the side effects of other cancer treatments.
- High-intensity focused ultrasound: This therapy directs high-energy sound waves (ultrasound) to cancerous tissues to kill cancer cells.
- Hormone Therapy: It prevents cancer cells from taking the hormones they need for growing.