Prostate cancer refers to the cancer that occurs in the prostate, a tiny, chestnut-shaped gland in the male reproductive system. Located underneath the bladder and in front of the rectum, the prostate gland surrounds the upper portion of the urethra, the channel that transports urine from the bladder through the penis. The gland secretes prostatic fluid which makes up semen and boosts sperm motility and viability. When certain changes occur in the cells of the prostate, they begin to grow abnormally or uncontrollably, resulting in prostate cancer.
How common is prostate cancer?
Prostate cancer is a serious health concern for men. While the condition is quite rare before the age of 50, it is common in elderly men of all races. Every year, there are more than 200,000 new cases and more than 27,000 cancer-related deaths due to prostate cancer. More than 75 percent percent of prostate cancer cases occur in men older than 65, but African-American men are more likely to have and die from the disease. Fortunately, the cancer spreads slowly and rarely causes symptoms until it has reached advanced stage. When detected and treated early, the cancer responds well to treatment.
What causes prostate cancer?
Prostate cancer is mainly a disease of older men, with more than 75 percent of cases occurring in men older than 65 and only about 1 percent of cases in men younger than 50. However, men with a family history of the cancer are at greater risk and may develop the cancer in their 30s or 40s. While the cause of prostate cancer is unknown by doctors, experts agree that certain factors increase the risk.
The factors include:
- Age: The risk increases with age such that white men with no family history of the cancer have greater risk after the age of 50 while African-American men with a family history of the cancer have greater risk after the age of 40. More than two-thirds of prostate cancer cases occur in men older than 65, but the older the patient (especially after age 70) the less aggressive the cancer.
- Family history: Men with relatives who have had the cancer are at greater risk. Having a brother or father who has had prostate cancer doubles your risk, while having multiple relatives who have had the cancer makes the risk even higher.
- Race: Prostate cancer incidence is 60 percent higher in African-American men than White-American men.
- Diet: High dietary fat increases the risk of prostate cancer. Studies have shown that men who consume meat and dairy products regularly are at greater risk than those whose diets frequently consist of vegetables, fruits, rice and soybean products.
- Certain job hazards: Rubber workers, welders, battery manufacturers and those frequently exposed to cadmium have increased risk of prostate cancer.
- Lifestyle: Low physical activity, being overweight and smoking make prostate cancer more likely or increase the risk of advanced-stage prostate cancer.
Symptoms of prostate cancer
Early-stage prostate cancer does not usually show any warning signs. However, once the tumor has caused the prostate gland to swell or has spread beyond the prostate, troubling symptoms will occur. Typically, the growth of the cancer will enlarge the prostate and cause urinary problems. The problems include:
- Frequent urge or need to pass urine, often at night.
- Interrupted or weak urine stream.
- Problems starting or stopping a urine stream.
- Leakage of urine when coughing or laughing.
- Burning sensation or pain when urinating or ejaculating.
- Blood in urine/semen.
As prostate cancer advances, it will show more specific symptoms such as:
- Discomfort in the pelvic region.
- Swelling of lower extremities.
- Trouble urinating.
- Paralysis or weakness in lower limbs (often with constipation).
- Decreased force in your urine stream.
- Loss of appetite, nausea, vomiting, fatigue or weight loss.
- Erectile dysfunction
- Bone pain.
When you experience any of these symptoms, make an appointment with your doctor immediately.
Prostate cancer screening
Screening means carrying out tests to detect prostate cancer in healthy men who are showing no symptoms. It is invaluable for detecting the cancer early when it still responds well to treatment. Medical organizations do not agree on when and why to undergo screening. While some recommend that men at average risk should start screening in their 50s and those at higher risk in their mid-40s, other organizations oppose screening. Because of this, it is important to discuss your situation with your doctor, understand the risks and benefits for your situation, and make screening decision together.
There are two tests commonly used to screen for prostate cancer:
- Prostate-specific antigen (PSA) test: This is a blood test that measures the amount of the prostate-specific antigen (PSA), which is naturally produced by the prostate gland. The level of PSA in blood is usually low, so when a higher-than-normal level is found then it is an indication of prostate inflammation, infection, enlargement or cancer.
- Digital rectal exam (DRE): A digital rectal exam (DRE) means the doctor inserting a gloved, lubricated finger into the rectum to examine the prostate. If the doctor detects any abnormalities in shape, size or texture of the gland, prostate cancer may be suspected and further tests are used to confirm the condition.
Diagnosis of prostate cancer
In the absence of symptoms, prostate cancer is screened using a digital rectal exam (DRE) and a prostate-specific antigen (PSA) test. These two tests may find abnormalities in the prostate that may indicate there is cancer. However, the tests are not definitive and further tests are used to confirm the cancer. The doctor will also get your medical history and ask you questions about your family and any urinary and genital symptoms. This information is combined with the test results to diagnose prostate cancer.
Tests used to confirm prostate cancer include:
- Ultrasound: A transrectal ultrasound can provide a clear picture of the prostate and confirm prostate cancer. The doctor inserts a small probe (about the size and shape of a cigar) into the rectum and uses sound waves to create pictures of the prostate gland.
- Biopsy: Prostate cancer is confirmed by collecting a sample of prostate tissue and examining under a microscope. A prostate biopsy is performed using a thin needle that is inserted into the prostate in order to draw a sample of prostate tissue. The cells in the tissue are carefully analyzed to determine whether they contain cancer cells.
Grading prostate cancer
Once the doctor has confirmed that you have prostate cancer, the next step is to grade the cancer to determine its aggressiveness. This is done in the laboratory where the prostate tissue obtained through a biopsy is examined to see the degree of difference between the cancer cells and healthy prostate cells. The observations are quantified using a scale, most commonly the Gleason score. The higher the grade on the scale the more aggressive the cancer and the faster it is likely to spread.
Staging prostate cancer
Apart from grading, the doctor also will want to know the stage of the cancer. The stage of a cancer means the extent it has spread beyond the prostate tissue. Staging is done using imaging tests such as bone scan, ultrasound, computerized tomography (CT) scan, magnetic resonance imaging (MRI) or positron emission tomography (PET) scan. The number of tests depends on what the doctor considers appropriate in any given situation. Following the tests, the doctor will assign the cancer a stage to be able to determine the right treatment.
Prostate cancer stages include:
- Stage I: Cancer still only confined to a small area within the prostate. It is early-stage cancer and is not considered aggressive.
- Stage II: Cancer still small but has grown and spread to both sides of the prostate gland. This stage is considered aggressive.
- Stage III: Cancer has spread outside the prostate and reached the seminal vesicles or nearby tissues.
- Stage IV: Cancer has invaded nearby lymph nodes and other organs such as bladder, urethra, lungs, bones or others.
Treatment of prostate cancer
There are several treatment options for prostate cancer and your doctor will consider many things before choosing the right treatment for you. The doctor will consider the size of the tumor, how far the cancer has spread, how quickly the cancer is likely to grow, your age and overall health, benefits and potential side effects of the treatment, and your preferences.
1. Watchful waiting (active surveillance)
When prostate cancer is diagnosed at a very early stage, treatment may not be necessary immediately. In fact, some people may never require treatment. Prostate cancer grows and spreads slowly and there may be no need to treat it if there are no symptoms or changes. The doctor may recommend watchful waiting (active surveillance), monitoring the growth or spread of the tumor closely using regular follow-up rectal exams, blood tests and possibly biopsies. If at any point of active surveillance the tests indicate that the cancer is progressing, the doctor may opt to use some form of treatment such as chemotherapy, radiation or surgery. Watchful waiting may be considered for men with other serious health conditions or whose cancer is at an advanced stage, making treatment difficult.
Surgical treatment of prostate cancer involves removal of part or the entire prostate. The type of operation depends on the position, shape and size of the tumor. Your doctor will explain to you the surgical options available and help you choose the right one. Surgical procedures for prostate cancer include:
(a) Robot-assisted surgery (robotic prostatectomy): This is a more precise minimally-invasive operation that allows the surgeon to make more accurate surgical movements. With the help of a robot (mechanical device) the doctor makes several small incisions to remove the tumor.
(b) Retropubic surgery (incision in the abdomen): Part or the entire prostate gland is removed through an incision made on the lower abdomen.
(c) Perineal surgery (incision between the scrotum and anus): An incision is made between the scrotum and anus in order to access and remove the tumor.
(d) Laparoscopic radical prostatectomy: The doctor makes small incisions in the patient’s abdomen with the help of a tiny camera (laparoscope).
Chemotherapy is the use of prescription drugs to kill or prevent the growth of cancer cells. The drugs can be administered through a vein, as pills or both. Chemotherapy is preferred treatment for men with advanced stage prostate cancer that has spread beyond the prostate and into other parts of the body. It also may be used to shrink the tumor prior to surgery or to kill remaining cancer cells after surgery. Chemotherapy is also an ideal option for prostate cancer that does not respond to hormone therapy.
4. Hormone therapy
Hormone therapy is the use of medications to stop the secretion of hormones that fuel the growth of prostate cancer. Often, the medications target hormone testosterone which helps cancer cells to grow. When the supply of testosterone is cut off, the cancer cells die or their growth is slowed down. Hormone therapy for prostate cancer includes:
(a) Luteinizing hormone-releasing hormone (LH-RH) agonists: These are drugs that stop the testicles from secreting testosterone. Examples of such drugs include triptorelin (Trelstar), histrelin (Vantas), goserelin (Zoladex), leuprolide (Lupron, Eligard), and abiraterone (Zytiga).
(b) Anti-androgens: These are drugs that prevent testosterone from reaching cancer cells. Examples of the drugs include nilutamide (Nilandron), flutamide, bicalutamide (Casodex), and enzalutamide (Xtandi).
(c) Orchiectomy (surgery to remove testicles): Removal of the testicles reduces the level of testosterone in the body.
Hormone therapy is commonly used for advanced stage prostate cancer to shrink and slow the growth of the cancer. But in men with prostate cancer in the early stages, hormone therapy is used to shrink tumors prior to radiotherapy in order to boost the success rate of treatment.
5. Freezing prostate tissue
Cryoablation or cryosurgery is the freezing of prostate tissue in order to kill cancer cells. During cryosurgery, small needles are inserted into the prostate with the help of ultrasound images. A very cold gas is put into the needles to help in freezing surrounding tissue. A second gas is put into the needles to re-heat the tissue, and then cycles of thawing and freezing are used to kill cancer cells and surrounding healthy tissue. With newer technologies, cryosurgery has been performed with high success rates and minimal complications.
6. Biological therapy (immunotherapy)
The body’s immune system can be used to safely and effectively fight prostate cancer. For instance, a therapeutic procedure called sipuleucel-T (Provenge) is effective in treating advanced stage prostate cancer. During the treatment, immune cells of the patient are taken and genetically re-engineered in the laboratory before being injected back into the body. The treatment is rarely used because it is expensive.
Radiotherapy is the use of high-energy particles or waves to kill cancer cells or shrink prostate tumor. The radiation is either delivered externally or internally.
(a) External beam radiotherapy: Prostate cancer can be treated using radiation that is delivered from a machine located outside the body. During external beam radiation therapy, the patient lies on a table and a radiotherapy machine is moved around the body, directing high-energy beams to the tumor site. Radiation treatments are done for 5 days (Monday through Friday) a week for 6 or more weeks.
(b) Brachytherapy (internal radiation therapy): During brachytherapy, many rice-sized radioactive seeds are surgically placed into the prostate tissue. The seeds gradually deliver low-dose radiation to the tumor over a period of time. Once radioactivity is used up from the seeds, they stop emitting radiation so they do not need to be removed from the body.
Side effects of prostate cancer treatment
Treatments for prostate cancer can have various adverse effects on the body. Common side effects include:
- Lower sex drive.
- Bowel problems.
- Erectile dysfunction.
- Loss of bladder control or leaky bladder.
The side effects must be carefully considered when choosing prostate cancer treatment. If a treatment has adverse effects that you cannot handle, your doctor should change the treatment approach. Speak with your doctor before treatment to find out potential side effects and how to manage them.