PROSTATE cancer is the second most common cancer in men worldwide and the fourth most common cancer in Malaysia.
The incidence of prostate cancer increases with age and it mainly affects people over 60 years old.
What is prostate?
Prostate is a small gland about the size of a walnut, located just below the bladder. It surrounds the first part of the urethra, which carries urine from the bladder to the penis. The prostate gland normally produces a thick clear fluid which forms an important part of semen.
The growth and function of the prostate gland depends on the male sex hormone testosterone.
Causes and risk factors
We do not know the exact causes of prostate cancer. However, research shows that having certain risk factors might increase the chance of getting prostate cancer. Having one or more risk factors does not mean that you will definitely get cancer and some patients develop cancer without having any risk factors at all.
The risk factors are:
- Family history
- Inheritance of the faulty gene such as BRCA1 or BRCA2
- Race (being black Caribbean and black African)
- Past history of vasectomy
- Having certain cancers in the past such as cancer of the kidney, bladder, lung, thyroid and melanoma of the skin
The risk of prostate cancer may be lowered by the following factors:
- Foods containing Lycopene (tomatoes and tomato based foods) and Selenium (vegetables, fish, shellfish, some meats, grains, eggs, Brewer’s yeast, and wheat germ)
- Having diabetes mellitus
However, it is still unclear whether taking Aspirin (an anti-inflammatory drug) regularly or being physically active protects men from getting prostate cancer.
Types of prostate cancer
More than 90% of prostate cancers are caused by adenocarcinoma, which arises from the gland cells in the prostate. Many of these cancers are very slow growing and are less likely to spread. However, some can grow more quickly and spread.
The treatment options discussed later on in this article are mainly based on prostate adenocarcinoma, because treatment for other rarer types of prostate cancer might be different.
Symptoms and signs
Benign prostate hypertrophy (BPH) is a very common condition in which the prostate gland enlarges in size when men get older. It is non-cancerous and men with prostate cancer can have symptoms very similar to BPH.
The symptoms and signs of BPH and prostate cancer are caused by the compression of the urethra, thereby obstructing the normal flow of urine from the bladder out of the body. As most prostate cancer arises from the outer part of the prostate, the urethra is not compressed until the prostate cancer has grown in size. This explains why many men with early prostate cancer do not have any discomfort or symptoms.
The symptoms of prostate cancer include:
- Needing to rush to the toilet to pass urine
- Passing urine more frequently than usual, especially at night
- Difficulty passing urine, including straining or stopping and starting
- A sense of not being able to completely empty the bladder
- Pain when passing urine
- Blood in the urine or semen
- Symptoms caused by cancer spread e.g. bone pain, leg swellings, etc.
Diagnosis and investigation
There are a few tests that can be done to confirm if a man has prostate cancer:
PSA blood test – PSA is a protein produced by normal and cancer cells of the prostate. Therefore both BPH, inflammation/infection of the prostate, and prostate cancer can cause a rise in the blood PSA level. In general, a reading of less than 10 ng/ml is usually caused by a non-cancerous condition of prostate gland. Non-cancerous prostate disease may also cause the reading to be higher than 10 ng/ml, but the higher the level of PSA, the more likely it is caused by cancer. It is also important to note that although some men have advanced prostate cancer, their PSA readings remain within normal levels.
Rectal examination – The doctor inserts a gloved finger into the rectum to feel the prostate gland for any abnormality such as hardness, lumpiness, nodules, etc.
Transrectal ultrasound – A small ultrasound device is inserted into the rectum to detect any abnormality. It also helps in taking a biopsy from the prostate gland.
Biopsy of the prostate gland – Taking some tissue samples from the prostate gland to be examined under a microscope is the best way to confirm whether a man has prostate cancer or not. It also give us details on the cancer appearance and differentiation as well as the exact type of prostate cancer.
MRI / CT scan and bone scan – An MRI (magnetic resonance imaging) of the pelvis/prostate is usually more accurate than a CT (computerised tomography) scan of the pelvis/prostate in telling us the changes/cancer in the prostate, whether the cancer is confined in the prostate gland or has spread outside of the prostate and into the normal surrounding organs such as the seminal vesicles, bladder, rectum or the pelvic lymph nodes. A bone scan and CT scan of the chest/abdomen may also reveal whether the cancer has spread to a more distant organ such as the bone, liver and lung.
The stages of cancer mean the extent of cancer spread and invasion. It can be broadly classified into Stage 1 to 4. The stages of cancer not only determines the treatment options but also predicts how likely the cancer can be controlled and cured after proper treatment. Therefore, the earlier the cancer stage, the better the outcome.
In general, Stage 1 to 3 prostate cancers are potentially curable with appropriate treatment. Stage 4 cancers are usually not curable but treatment might help to relieve cancer-related symptoms and improve life expectancy.
Prostate cancer can also be classified into Low, Medium and High risk groups, depending on the cancer stage, PSA reading and cancer grade (Gleason grade). Patients with lower risk groups also have a better outcome and prognosis.
Prostate cancer treatment might be different from one person to another. This is because a few factors as below will need to be taken into consideration before the cancer treatment plan is offered to the patient:
- The cancer stage, initial PSA reading, and the Gleason grade
- Risk group and type of prostate cancer
- Patient’s fitness and preferences of treatment option
- Underlying medical problems
- Cost and availability of treatment
The standard treatment options of prostate cancer include surgery, radiotherapy (internal radiotherapy with iodine seed implant and/or external radiotherapy), hormonal and chemotherapy treatment.
Sometimes a combination of different treatments is given to patients in order to increase the chances of cancer control and/or cure.
There have been many advances in prostate cancer treatment options and techniques in recent years. One example is that external radiotherapy treatment has become more precise and accurate with the use of new machines/techniques such as IMRT (Intensity Modulated Radiotherapy) and IGRT (Image Guided Radiotherapy). This helps improve cancer control/ cure rate and at the same time minimises the risk of side effects by reducing the exposure of radiation to the normal surrounding tissues and organs.
All cancer treatment options have their own merits and disadvantages. Therefore, it is essential for patients to have proper consultations and discussions with their treating urologist and/or oncologist before they embark on their cancer treatment journey.
Dr Ng Yi Siang is the consultant clinical oncologist at Subang Jaya Medical Centre Ramsay Sime Darby Healthcare.