Prostate cancer is the commonest adult cancer in Australian men after skin cancer. Annually over 20 000 Australian men are diagnosed with prostate cancer, and about 6000 men succumb to the disease. However, the individual risk of dying from prostate cancer is quite low, however the disease can recur after curative treatment, and for this reason men are usually kept on long term surveillance, either via their urologist or GP.
The diagnosis of prostate cancer is first considered when a man has a blood test showing an elevated level of PSA. PSA stands for "prostate specific antigen", but this protein is actually an enzyme secreted in the prostate fluid and it has an important role in assisting sperm function. The PSA blood test is a very poor quality detection (or "screening") test for prostate cancer as the levels can be raised for many reasons, including benign enlargement (non-cancerous growth) of the prostate, cancer, infection or inflammation, recent intercourse, use of certain drugs like Voltaren and Brufen, and even excessive hours on a bicycle saddle. The level of the test also flucuates by small amounts naturally from test to test. For this reason a lot of criticism has been levelled at the use of the test as a screening tool. This criticism has come from government agencies around the world, epidemiologists, public health specialists and GP bodies. The criticism focuses mainly on the use of the test as an indiscriminate screening tool (i.e. the test is ordered "just in case" in a man). Of all men with a raised PSA test, only about 30-50% will end up having a diagnosis of prostate cancer. However, the PSA test is currently the only widely available test or indicator that we should look closer in a particular individual, as prostate cancer causes no signs or symptoms until very late in the disease process. Currently, the Urological Society of Australia and New Zealand (USANZ), the professional body representing urologists in both countries, recommends that men have a first PSA test at the age of 40, or between the ago of 40 and 50, to determine their lifelong risk of prostate cancer. If the level is above 1.0 at age 40, a man has a higher risk of developing prostate cancer in the course of his life. The acceptable cutoff level for PSA rises with age, owing mainly to growth of the prostate, so that after age 65 a level up to 6.5 is acceptable and in the "normal range". However prostate cancer can exist at any PSA level. For this reason a rectal exam by your GP and assessment by a urologist is important in the process of ruling out prostate cancer.
The causes of prostate cancer are not well understood. Age and family history are important. Most diagnoses of prostate cancer occur in men over the age of 60. Ten to 15% of cases have a family history of the disease (i.e. a male relative like a father or brother, or paternal uncle who had it). Other factors that are possibly important include infection or inflammation of the prostate, diet, smoking, obesity and ethnicity. Prostate cancer is less common in men of Asian ethnicity than in Caucasians or African men.
Prostate cancer is traditionally diagnosed by performing a prostate biopsy in a man suspected to be at risk of the disease. This is done using a needle biopsy device, which is passed into the prostate under ultrasound guidance, either via the rectum or through the skin behind the scrotum. These techniques need either local anaesthetic or sedation if done via the rectum or a general anaesthetic if done through the skin behind the scrotum ("transperineal").
In Brisbane, Dr Pokorny and Dr Les Thompson pioneered the use of prostate MRI imaging in the diagnosis of prostate cancer. Our trial, published in the top urology journal European Urology in 2014, showed that using MRI in the diagnosis of prostate cancer is far more accurate than the traditional method of blind biopsies. In addition, we can avoid biopsy of the prostate altogether. We can also diagnose more "significant" cancers - the dangerous cancers that we need to treat, and avoid diagnosing "insignificant" cancers, which pose no real risk to the individual. Urologists have been criticised in the past for diagnosing too many insignificant prostate cancers and harming men through the side effects of unnecessary treatment. We believe that MRI has given us a very powerful tool to reduce this overdiagnosis and overtreatment problem, while at the same time helping us find aggressive cancers that might have been missed with the traditional "blind" biopsy methods.
Once a cancer is diagnosed, your urologist will order "staging" investigations. These are scans looking for any evidence of spread outside the prostate. Prostate cancer will usually first spread to the lymph glands in the pelvis, or the bones of the lower back, pelvis or hips and femurs. Most urologists will therefore order a CT scan to look at the lymph glands and a bone scan to look at the skeleton. In some centres we are now using a PSMA scan, which is a combination of a CT scan and a nuclear medicine scan using PSMA. PSMA is a protein expressed on the surface of most prostate cancer cells. If there is no evidence of cancer spread (metastasis) on these scans, and depending on the age and PSA level of the patient, most patients will be offered curative treatment for "significant" cancers.
This can take the form of:
- Surgery to remove the prostate - open, laparoscopic or robot-assisted prostate removal ("radical prostatectomy")
- Internal radiation in the form of brachytherapy seeds placed directly into the prostate
- External beam radiation, in which the prostate is irradiated with daily sessions lasting 7 weeks
- A combination of 2 and 3
The reasons for selecting a particular treatment, and the risks and benefits, is a complex discussion, and should be held with your urologist and a radiation oncologist. Some useful information for this area can be found on the Resources page.
As mentioned above, after curative treatment, prostate cancer can come back or recur in up to 15% of men. This is usually due to microscopic spread which was not visible on the staging scans, and can occur many years after the curative treatment occurred. For this reason the PSA test is used as surveillance after treatment. If the prostate is removed, the PSA should be less than 0.01 for the rest of the patient's life. In the case of radiation therapy, the PSA will drop quite low, usually less than 1.0 or even 0.5. It should then stay low for a long time. In either case if the PSA starts to rise it usually suggests a return of prostate cancer somewhere in the body. This can be in the prostate if still present, near where the prostate was or in the lymph glands or bones of the pelvis. In this scenario further staging scans are needed and treatment options are multiple and depend on numerous factors.