Prostate Cancer

The prostate gland is part of the male reproductive system. Prostate cancer is a disease which develops from the tissues of the prostate, a gland located below the bladder and in front of the rectum.

In most cases, prostate cancer is slow-growing and is confined to the prostate gland. It typically takes a number of years to become large enough to detect, and even longer to spread beyond the prostate. However, there are some aggressive forms of prostate cancer that can spread quickly.

Prostate cancer is the second most common cancer in men in Singapore. During a period of five years, from 2014-2018, 5368 cases of prostate cancer were diagnosed in Singapore.

Prostate cancer usually occurs in men over the age of 50 and is mostly seen in those over the age of 70.

There are usually no symptoms in the early stages of prostate cancer. As most prostate cancers are slow growing, many men reach old age or pass away without knowing that they have prostate cancer. Most men discover they have prostate cancer during routine medical check-ups or through blood tests.

Symptoms, which typically occur in more advanced prostate cancer may include:

• Difficulty passing urine
• Increased urinary frequency, especially at night
• Weak, interrupted urinary stream
• Burning or pain during urination
• Blood in urine
• Blood in semen
• Weight loss
• Loss of appetite
• Pain in the back (spine), hips, chest (ribs), pelvis or other bony areas
• Weakness or numbness in the legs and difficulty walking
• Difficulty controlling the bladder or bowels

When to see a doctor

The symptoms above can be caused by a number of reasons and may not indicate the presence of cancer. However, make an appointment with your doctor if you have any signs or symptoms that worry you.

At present there is a lack of evidence to support population-based screening for prostate cancer in Singapore. Individuals should seek medical attention if they have any of the above symptoms.

Currently there are no proven preventive strategies. However, adopting a healthy lifestyle can help prevent the risk of prostate cancer. This includes:

• Eating a diet rich in fruit, vegetables and whole grains, while limiting the consumption of fat
• Quitting or not starting smoking
• Limiting alcohol consumption
• Regular exercise

The exact causes of prostate cancer are still unknown and are being studied through research. Some of the risk factors that are known to increase the risk of developing prostate cancer are:

• Age − This is the strongest risk factor. Men above the age of 50 are at risk and the risk increases with age.
• Ethnicity − In Singapore, Chinese men have double the risk of getting prostate cancer compared to Malay or Indian men.
• Family history – Men with a father or brother with prostate cancer are more likely to get the disease. The risk is higher for men who have a brother with prostate cancer than for those with an affected father. Risk is also much higher for men with several affected family members, especially if they were young when the cancer was detected.
• Diet − Men who consume large amounts of fat, particularly from red meat and other sources of animal fat, including dairy products.

Several different tests can be used to diagnose prostate cancer, including:

• Digital rectal examination
  • Often part of a routine physical examination, the doctor inserts a lubricated gloved finger into the rectum and gently feels for abnormal growths. This may be uncomfortable but should not be painful.
• Prostate-Specific Antigen (PSA) blood test
  • A blood test that measures PSA levels in the blood may indicate prostate cancer. The PSA is a substance produced by the prostate and a small amount of it is normal. Men with prostate cancer tend to have higher levels of PSA in their blood. As elevated PSA levels may be caused by other non-cancerous conditions, additional tests are needed to confirm the presence of cancer.
• Transrectal Ultrasound scan (TRUS)
  • This test uses high-frequency sound waves to produce images of the prostate. It is done by inserting a small probe into the rectum. TRUS is often conducted if a man has an abnormal digital rectum exam or a high level of prostate-specific antigen (PSA). It is also commonly used during a prostate biopsy, to allow the doctor to see where to take small samples of tissue from.
• Biopsy
  • A prostate biopsy involves taking small samples of prostate tissue for further examination in the lab to determine the presence of cancer cells. Prostate biopsy samples can be collected in different ways, by inserting a thin needle either through the rectum (transrectal biopsy) or through the area between the anus and scrotum (transperineal biopsy).
• Computer Tomography (CT) scan
  • A CT scan takes X-ray images from different angles to build up a 3D picture of the inside of the body. This can identify the area of the cancer and any spread to nearby structures or body parts.
• Magnetic Resonance Imaging (MRI) scan
  • An MRI scan uses magnetic fields to give detailed pictures of the pelvic area. It can help to detect cancer and look for any spread to the lymph nodes.
• Bone scan
  • A bone scan can detect if cancer has spread from the prostate to the bones. A small amount of radioactive material called a tracer is injected and a scan is done to see how the tracer is absorbed, to indicate the presence of cancer.
• Positron Emission Tomography - Computed Tomography (PET-CT) scan
  • A PET-CT scan combines both a CT scan and a PET scan to provide a more comprehensive view of the cancer and the extent of its spread. A CT scan uses X-rays to take images to check for any areas with abnormalities. With the PET scan, a radioactive glucose solution is injected and absorbed by cells in the body that are growing quickly, indicating the presence of cancer, which can be seen with a special camera. The PET scan helps to show if areas with abnormalities seen on the CT scan are suspicious for cancerous growth.

Treatment for prostate cancer depends on several factors including the patient’s age, medical conditions, significant illnesses, prostate-specific antigen level, digital rectal examination results, aggressiveness of the cancer and spread of disease.

An individual with prostate cancer should be assessed by a multi-disciplinary team of specialists to determine which modality of treatment is best suited for them. Prostate cancer treatment requires the involvement of different specialists – urologists, interventional radiologists, nuclear medicine physicians, medical oncologists, radiation oncologists and palliative medicine specialists. Such multi-disciplinary care is available at SingHealth healthcare institutions. It is important to discuss all the possible treatment choices, including what to expect and possible side effects, to help you make an informed decision.

Types of approaches and treatments

Active surveillance

Men with early-stage prostate cancer, that is slow-growing and causing little or no symptoms, may not need immediate treatment. In such cases, their doctors may advise waiting and observing to see if the cancer progresses before starting any treatment. Active surveillance may include regular tests such as prostate-specific antigen level blood test or digital rectal examination.

Surgery

The surgical approach to treating prostate cancer is known as prostatectomy. It involves removing all or part of the prostate gland. Surgery is usually offered to men with early-stage disease or cancer that is confined to the prostate, who do not have other serious health problems.

In radical prostatectomy, the entire prostate gland and other nearby tissues (e.g. surrounding structures and lymph nodes) are surgically removed.

Another approach is the robotic-assisted laparoscopic radical prostatectomy, where the urologist makes several small incisions in the lower abdomen and uses instruments attached to a mechanical device, known as “robotic arms”, to perform the surgery.

Tissues that have been surgically removed will be examined to indicate how advanced the cancer is, the risk of cancer recurrence and if additional treatment is necessary.

Hormone therapy

Hormone therapy, known as androgen deprivation therapy, works by preventing cancer cells from receiving testosterone, causing the cancer cells to die or grow more slowly. Hormone therapy for prostate cancer usually involves the use of drugs, given as injections or tablets. Another less common form of hormone therapy is the surgical removal of the testicles or the parts of the testicles that produce testosterone.

Radiotherapy

Radiotherapy, also known as radiation therapy, is the use of high-energy radiation (rays or particles) to kill or damage the prostate cancer cells. Radiation affects both normal and cancer cells. Generally, cancer cells are more sensitive to radiation and more cancer cells are killed compared to normal cells. Normal cells are also better able to repair themselves after radiotherapy.

Radiotherapy can be delivered in two main ways; external beam radiotherapy (EBRT) or internal radiotherapy. In EBRT, radiation beams are generated from a machine outside the body and directed at the prostate. For Internal Radiation Therapy, also known as Brachytherapy, radiation is delivered to the prostate by placing radioactive materials in the prostate.

The type of radiotherapy the doctor would recommended depends on the stage of the cancer and the patient’s underlying health condition.

Chemotherapy

Chemotherapy is the use of anti-cancer drugs to eradicate cancer cells or prevent their growth. Chemotherapy can also help to relieve or delay symptoms like pain. Early stage prostate cancer is not usually treated with chemotherapy. Chemotherapy is mostly offered to men with advanced or metastatic prostate cancer, which has spread beyond the prostate to other parts of the body. It is commonly given to those who have not responded to hormone therapy.

Your urologist will perform a comprehensive medical work-up including blood tests, exams and scans to see if you are suitable for surgery and advise you on the risks involved. This treatment recommendation is often based on consensus by a group of different specialists' opinions (tumour board) which weighs the pros and cons of every treatment strategy.

Before surgery, the anaesthesia team will also assess your fitness for surgery and advise you on various aspects of general anaesthesia and pain control after surgery.

Specialist nurses will also provide pre-surgery counselling.

After recovering from surgery, you will be given regular outpatient appointments to see your team of doctors. These visits may include blood tests and scans to monitor and check if the cancer recurs.

It is important to follow your doctor's advice, keep to scheduled clinic visits and do the prescribed tests so that timely treatment can be administered if the cancer or other problems arise.