Prostate cancer is a disease where malignant (cancer) cells form in the prostate tissue. It is the third most common cancer in Singaporean men and the most common cancer in American men.

Early prostate cancer is usually asymptomatic. Symptoms of prostate cancer usually show up at later stages of the disease as the tumour grows and narrows the urethra (urine passage) and when it spreads to other organs.

The following symptoms are nonspecific and may also be caused by benign (non-cancerous) conditions such as benign prostatic hyperplasia and prostatitis. They include :

• Weak or interrupted flow of urine
• Frequent urination (especially at night)
• Difficulty urinating
• Pain or burning during urination
• Blood in the urine or semen
• Nagging pain in the back, hips, or pelvis
• Painful ejaculation
  

Prostate cancer is found mainly in older men above 50 years old. Those with a family history of prostate cancer are at slightly higher risk.

Several abnormal parameters, including clinical fi ndings and laboratory tests, can help to diagnose prostate cancer :

• Abnormal digital rectal examination (DRE). The doctor or nurse examines the prostate by inserting a lubricated, gloved fi nger into the rectum and feeling the prostate through the rectal wall for lumps or abnormal areas.
  
• Elevated prostate specific antigen (PSA) level in the blood. PSA, a substance made by the prostate may be found in increased amounts in the blood of men who have prostate cancer. PSA levels may also be high in men who have an infection, infl ammation or an enlarged noncancerous gland.
• Transrectal ultrasound guided biopsy of the prostate showing presence of cancer cells. This is a procedure in which an ultrasound probe about the size of a finger is inserted into the rectum to check the prostate. The probe is used to bounce high-energy sound waves (ultrasound) off internal tissues and make echoes. Cells are removed by a thin needle under a local anaesthetic and viewed under a microscope by a pathologist.
• CT scan or MRI of the pelvis. This is a detailed scan of the pelvis that helps to identify the extent of cancer involvement after biopsy confirmation of cancer.
  

The decision on the choice of treatment depends on the prostate cancer profile. This profile depends on several factors, including :

• Age and expected actuarial survival
• Medical condition and risk factors
• Presence of significant illnesses, such as myocardial infarction, stroke, diabetes, etc.
• PSA level
• Gleason Score (derived from the pathologist’s assessment of the prostate biopsy)
• Presence of metastasis (extensive spread of disease)
• Status of DRE (digital rectal examination)

There are different types of treatment for people diagnosed with prostate cancer.

Active surveillance

Selected persons may be closely monitored by blood tests and repeat biopsies and treatment is initiated when there is evidence of cancer progression. This is usually used in older men or men with early-stage small volume cancer who are willing to comply with the follow-up protocol.

Surgery

Those in good health are usually offered surgery as treatment for prostate cancer. Known as radical prostatectomy, this is a surgical procedure to remove the prostate, surrounding tissue, and seminal vesicles. Depending on their cancer profile, the pelvic lymph nodes around the prostate gland may also be removed in selected cases.

This procedure allows the removal of the entire prostate gland, enabling a complete examination by pathologists. This histological assessment will tell us how advanced the cancer is, the risk of cancer recurrence and if additional treatment will be needed. As the prostate gland is removed, the PSA level will drop to undetectable levels. This helps doctors to monitor for recurrence. Radiation can be given after surgery, if necessary.

The surgery is performed in two ways :

• Open radical retropubic prostatectomy. The prostate gland with the attached seminal vesicles and vas deferens are removed via a 15 cm incision below the navel in the midline of the abdomen.

• Da Vinci robot-assisted laparoscopic radical prostatectomy. The same operation is performed via special laparoscopic instruments through fi ve to six keyhole-sized incisions in the abdomen. These instruments are manipulated by the robotic arms of the Da Vinci surgical robotics system that are controlled by surgeons. This technique allows a magnifi ed, threedimensional view of the operating fi eld and allows the exact surgery to be performed with smaller incisions with less bleeding, allowing for faster recovery and less post-operative pain.
  

Complications of prostatectomy

Some men may experience mild to moderate amounts of urinary leakage especially immediately after surgery. Most patients show signifi cant improvement within three months after surgery. Some may experience diffi culties with erection and require alternative treatment for impotence.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays to kill cancer cells or keep them from growing. There are two types of radiation therapy :

• External beam radiation therapy uses a machine outside the body to send radiation towards the cancer in the prostate. Patients may require pre-treatment gold seed implant in the prostate to improve the consistency of radiation therapy. The treatment usually lasts about seven weeks, and may require additional hormonal therapy in addition to the radiation.

• Brachytherapy or internal radiation therapy involves small radioactive seeds implanted directly into the prostate. It is performed under anaesthesia and involves the mapping and evaluation of the prostate to estimate the number of radioactive seeds needed for a given brachytherapy procedure. Radioactive iodine and palladium are used to deliver the energy into the prostate.

Complications of radiation therapy

Radiation cystitis (inflammation of the bladder) and radiation proctitis (inflammation of the rectum) can occur after treatment as the radiation often has to travel through the bladder and the rectum. Most symptoms improve after the radiation treatment is completed.

 

The radiation oncologist will sometimes suspend radiation if the side effects are signifi cant and will resume once the symptoms have subsided. There is an increased risk of bladder cancer and/or rectal cancer in men treated with radiation therapy. Impotence and urinary problems may occur in men treated with radiation therapy.

Hormonal Therapy

In prostate cancer, male sex hormones can cause prostate cancer to grow. Hormonal therapy works by removing the source of male hormones or opposing its action on the tumour cells with drugs or surgery. Drug treatment may be in the form of subcutaneous or intramuscular injections (luteinising hormone releasing hormone agonists or antagonists) or oral medications (antiandrogens, ketoconazole or oestrogens). Surgery involves removal of both testes (orchiectomy), which is the main source of male hormones. Hot flashes, impaired sexual function, and loss of desire for sex may occur in men treated with hormone therapy.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or stopping them from dividing. Chemotherapy is usually given to patients in an advanced stage of prostate cancer when they are no longer responsive to hormonal treatment. Patients may experience nausea, hair loss (alopecia), inflammation of the cheeks, gums, tongue, lips, and roof or floor of the mouth (stomatitis) and abnormal blood profile that increases the risk of infection.

Treatments under clinical trials

High-intensity focused ultrasound
This is a treatment that uses ultrasound (high-energy sound waves) to destroy cancer cells. To treat prostate cancer, a probe is placed in the rectum to make the sound waves.

Immunotherapy
This is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.