Prostate cancer develops in the prostate gland and is the most diagnosed male malignancy. It accounted for 1.3 million new cases worldwide in the year 2018; it is the third-leading cause of cancer death in men globally. In developing countries like India, there is an increasing trend in the incidence of prostate cancer.
About prostate cancer
The prostate is a small walnut shaped gland in men and is responsible for the production of semen. It is located underneath the urinary bladder in front of the rectum.
Prostate cancer develops when cells in the prostate gland begin to grow in an uncontrolled way forming a tumor. About 90% of prostate cancers are adenocarcinomas in which the cancers develop from the gland cells that produce seminal fluid.
Prostate cancer is of two types:
- Aggressive prostate cancer or fast-growing prostate cancer: This type of cancer grows rapidly and has a higher chance to spread to other parts of body, such as bones.
- Non-aggressive or slow-growing prostate cancer: This type of cancer grows slowly and rarely spreads to distant parts of the body.
Signs and symptoms
Early prostate cancer usually causes no specific symptoms. As the cancer advances, one may experience the following symptoms:
- Frequent urination
- Weak or interrupted urine flow
- An urge to urinate frequently at night
- Blood in the urine (Hematuria)
- Dull pain in the lower pelvic area
- Blood in the seminal fluid
- Painful ejaculation
- Swelling or fluid buildup in the legs or feet
- Unexplained weight loss
- Change in bowel habits
Even though the exact cause of the development of prostate cancer is unknown, researchers believe that prostate cancer may develop due to sudden changes in the cells of prostate gland. However, there are some factors that may increase the risk of prostate cancer. These include:
- Older age, especially after 50 years
- Family history of prostate cancer
- Inherited genetic mutations like Lynch syndrome
- Exposure to certain chemicals
- Unhealthy eating habits
Prostate cancer is asymptomatic during the early stages. So, any individual between 55 to 69 years of age with a family history of prostate cancer is recommended to undergo regular screening. Prostate cancer can be screened with the following tests:
- PSA Blood Test: The prostate-specific antigen (PSA) blood test measures the level of PSA protein in the blood; and elevated level may indicate prostate
- DRE: The digital rectal examination (DRE) involves inserting a gloved, lubricated finger into the rectum to check for any abnormalities in that area.
- Tumor marker test: Tumor markers are proteins that are secreted by the cancer cells. Presence of such markers in blood indicates cancer. Biomarker tests for prostate cancer include the 4Kscore and Prostate Health Index (PHI).
If prostate cancer is suspected from initial examinations, the following tests may be recommended for further evaluation:
- Transrectal Ultrasound (TRUS): TRUS can help calculate the PSA density or can be combined with MRI for a detailed examination of the suspicious area.
- Biopsy: A small sample of the suspected tissue is removed and examined under a microscope to determine if it is cancerous or non-cancerous. The procedure is guided by a CT or an MRI scan. A core needle biopsy is usually the type of biopsy done to diagnose prostate cancer.
- PCA3 test: It is an assay test to identify the PCA3 gene in the urine sample. Elevated levels of PCA3 gene indicate prostate cancer.
When these tests confirm the presence of cancer, it will be graded using the Gleason score. Higher grades are for aggressive cancers that are more likely to grow and spread quickly. Lower grades are for normal prostate tissues. If the cancer has a high Gleason score, imaging test like whole body bone scan, computerized tomography (CT) scan, magnetic resonance imaging (MRI) are done to determine the extent of its spread.
Stages of prostate cancer
The prostate cancer staging is done using the Tumour, Node, and Metastasis (TNM) staging system. It provides detailed information about:
- The size and extent of the tumour
- Whether the cancer has spread to the surrounding lymph nodes
- Whether the cancer has spread to distant parts of the body
Based on this system, the prostate cancer has following stages:
- Stage I: Cancer cells are slow growing. The tumor cannot be felt and involves less than one-half side of the prostate.
- Stage II: Cancer cell are confined to pancreas. The tumor is large enough to be felt on a rectal examination.
- Stage III: Cancer cells have grown outside the prostate gland and may have invaded into the nearby structures, such as the bladder or rectum, but not to the distant parts of the body.
- Stage IV: Cancer has spread to distant parts of the body, such as bones and lungs.
Treatment options of prostate cancer are based on the aggressiveness of the tumor, the stage of cancer at the time of diagnosis and overall health. Treatment modalities for prostate cancer are:
Observation/ Active surveillance: It does not help treat cancer, instead it helps to monitor the slow-growing tumors. Regular screening, routine follow-up blood tests, rectal examinations are performed to monitor the progression of cancer. If the test results indicate cancer progression, then treatments are decided to remove or destroy the cancer.
Surgery: It is recommended when the cancer is situated locally in the prostate gland. Surgery involves removal of the prostate and surrounding lymph nodes. Types of surgeries include:
- Prostatectomy: It involves the removal of entire prostate gland and the seminal vesicles to remove the cancer cells.
- Robotic assisted prostatectomy: This is a highly specialized procedure, in which the surgery is performed using the robotic arms that hold the surgical instruments and a camera, controlled by a surgeon in the console. It is recommended for the treatment of clinically localized prostate cancer located in a tightly confined area or is close to nerves that can affect urinary and sexual functions. This is less invasive than the manual procedure and has a better prognosis.
- Bilateral orchiectomy: It is usually recommended for locally advanced and metastatic pancreatic cancers. This procedure involves removal of both testicles. The surgery helps in stopping the production of testosterone and its action on the prostate cells.
- Transurethral resection of the prostate (TURP): In some cases, the tumour may block the bladder and cause difficulty in passing urine. During a TURP, a resectoscope (a thin metal tube containing a light and tiny camera at one end) is inserted through the urethra into the prostate. A surgical tool is then passed through the tube to remove the blockage.
Radiation therapy: It uses high energy radiations like X-rays to destroy the cancer cells. Depending upon the stage, the radiation therapy is used:
- As the first-line treatment for cancer
- As a part of the main treatment
- As an adjuvant treatment to prevent the recurrence of cancer
- To manage symptoms caused by advanced cancer
Depending on the stage of cancer, radiation therapy is given either externally through an external source or internally by placing a radiation source near the tumor to deliver high dose rays.
Hormone therapy: It is used to block certain hormones that aid in the growth of cancer cells. Lowering androgen often makes prostate cancers shrink or make them grow slowly for a time. It is often used with other treatment options to prevent the recurrence.
Chemotherapy: This involves the use of potent drugs to stop the cancer cells from growing further or to destroy them. It is usually used for cancers that have spread beyond the prostate gland and are no longer responding to the hormonal therapy.
Cryotherapy: This involves the usage of extremely cold temperatures to freeze and kill prostate cancer cells. It is recommended for patients with low risk early-stage prostate cancer who cannot have surgery or radiation therapy.
Immunotherapy: It involves the use of specific drugs to stimulate a patient’s own immune system to recognize and destroy cancer cells more effectively.
How to prevent prostate cancer?
There is no absolute way to prevent prostate cancers. Managing certain risk factors may reduce the risk of developing the cancer. These include:
- Practice healthy eating habits. Include foods like soy, tomatoes, fish, omega-3 fatty acids rich oils, cruciferous vegetables, and fruits in your diet.
- Manage your body weight.
- Exercise regularly.
- Limit alcohol and quit smoking.
Unlike other cancers, prostate cancers generally tend to grow slowly with relatively low risk and limited aggressiveness. The survival rates depend on the stage of cancer at the time of diagnosis. The average five-year survival rate for patients with stage I and II prostate cancer is 100%. The rate decreases to 31% for stage IV cancer patients. Advanced treatment options and healthy living habits will help in better outcomes.
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