What is the prostate?
The prostate gland is a small, solid gland roughly the size of a walnut, located behind the pubic bone. It is situated beneath the bladder, enclosing the first part of the urethra (water passage). Approximately 0.5ml of each ejaculate is fluid made by the prostate, containing a number of substances that nourish the sperm and are necessary for fertility. Two small pouches, the seminal vesicles, sit directly behind the prostate, and provide a further 2ml of ejaculatory fluid via small tubes that run through the prostate into the urethra, the ejaculatory ducts.
What diseases can affect the prostate?
Cancer is a condition in which the growth of normal cells becomes uncontrolled for reasons not entirely understood. These cells continue to divide, creating a tumour which at first grows locally within the prostate, then may spread via the lymphatics or blood stream to more distant parts of the body. Prostate cancer most commonly affects the outer part of the gland, and is often slow growing over many years. It does not usually cause any symptoms until locally advanced. One in six Australian men are diagnosed with prostate cancer in their lifetime, and it is the second most common cause of death from cancer in men.
Benign prostatic hyperplasia (BPH):
This is a gradual enlargement of the central portion of the prostate, that compresses the urethra and causes obstruction to urine flow.
The prostate can be infected, usually through the urine, and can be a source of recurring urinary infections, particularly in the setting of BPH and urinary obstruction.
What is PSA?
One of the substances secreted into the ejaculate by the prostate, Prostate Specific Antigen (PSA), is made in larger amounts when prostate cells become cancerous, and can be measured in the blood. This is therefore used as a screening test for prostate cancer. It is not a perfect test however, and only around a third of men with an elevated PSA go on to have a diagnosis of prostate cancer made. Causes of an increased PSA other than cancer include:
Recent urological procedure
Who is at risk of prostate cancer?
The exact reason for prostate cells turning cancerous is not understood. A number of factors have been determined to identify those at higher risk of prostate cancer, and these include:
Family history: Those with a first degree relative (brother or father) are around 2-3 times higher risk than normal, and this increases if more than one relative is affected
Age: the risk of prostate cancer increases with age, being rare in men under 50, and most commonly diagnosed in 60-70 year olds
Genetics: Prostate cancer is more common in Africans and rarer in Asians
Dietary factors: There appears to be a link between prostate cancer, and those consuming large amounts of dietary fat. Conversely, other substances such as anti-oxidants, selenium, and lycopenes, may play a protective role
What are the symptoms of prostate cancer?
As prostate cancer affects the outer part of the gland most commonly (ie away from the urethra), it does not cause symptoms until it is advanced. As such it is often recommended to test asymptomatic men to ‘catch’ the disease early in its course when there is a greater chance of cure
Urinary symptoms are more often due to co-existing BPH, such as:
hesitancy (difficulty starting urination)
poor or intermittent urine flow
feeling of the bladder not emptying completely
feeling of not being able to hold on (urgency)
If prostate cancer spreads to other parts of the body, such as into the bones, it may cause symptoms in these areas such as pain.
Stage and Grade of prostate cancer:
These are used to determine how advanced or aggressive the cancer is and therefore the likelihood of cure with treatment such as surgery or radiotherapy.
The stage refers to how far the prostate cancer is spread, and a classification system commonly used in Australia is outlined below in a simplified form. (By convention, the prefix T is used to denote the tumour stage, eg T1 or T2)
T1 – the cancer is too small to be felt on rectal examination. It has been diagnosed either through biopsy after an elevated PSA, or by chance after transurethral prostate resection.
T2 – the cancer is large enough to form a palpable lump on rectal examination, but is still confined to the prostate gland
T3 – the cancer has spread outside the gland and possibly into the seminal vesicles
T4 – the cancer has spread to involve structures around the prostate, such as the rectum, bladder, or pelvic muscles
The grade of a cancer is how aggressive the cells look under the microscope, which is an indication of how quickly they are growing. A system of grading was described by the pathologist Donald Gleason, and is therefore called the ‘Gleason score.’
As prostate cancer is often multifocal and consists of multiple spots of cancer within the prostate rather than one discrete tumour, separate areas of cancer can have slightly different appearances. In Gleason grading, the two appearances most commonly seen are graded out of 5, with 1 being least likely to have spread, appearing most like normal prostate cells, and 5 being most aggressive and appearing as sheets of cells with no resemblance to normal prostate tissue. These two Gleason grades are combined to produce a Gleason score out of 10, and the higher the score, the faster the cancer is growing and the less likely treatment is to cure the cancer.
Treatment options for prostate cancer:
There are many ways to treat cancer that is still confined to the prostate (T1 or T2) and there is still no definite agreement as to which is the best. One of the reasons for this is that patients with early stage disease may live 10 years or more if no treatment is used, whereas in others the disease can be more serious and progress quickly. While we can generalize, it is impossible to predict with certainty for any one individual the course their particular cancer may take.
The first thing to note is that you should not feel pressured to make a decision. When prostate cancer is detected early, there is plenty of time to explore your options, and it is not uncommon for patients to take a few months to decide upon which treatment they would prefer.
If their cancer has been diagnosed very early or incidentally during transurethral prostate resection, a ‘wait and see’ policy may be chosen to assess if the cancer is growing quickly enough to warrant treatment. This does not mean do nothing, but involves a regime of regular PSA measurements and sometimes repeat prostate biopsies to monitor the cancer. If treatment is ultimately required, it may be in the form of curative treatment (such as surgery or radiotherapy), or control with hormonal therapy (particularly in the elderly or those with other medical conditions posing a more serious threat)
This is the traditional form of treatment for prostate cancer, and involves removal of the entire prostate gland along with the seminal vesicles and attached vas deferens. The urethra is then reattached to the bladder opening. For cancer confined within the prostate, this offers complete removal and subsequent analysis of the specimen for a more accurate prediction of cure. Following surgery the PSA drops to undetectable levels and is monitored closely. A rise in PSA after surgery is an indicator of very early cancer recurrence, and this may be further treated with radiotherapy in some patients.
Laparoscopic radical prostatectomy
Radical prostatectomy historically was performed as an open procedure, most often through a cut between the belly button and pubic bone. Since 2000, keyhole approaches to this operation have been developed, called laparoscopic radical prostatectomy. When performed by a surgeon who has undergone specialized training in this procedure the advantages include a better view of the operation for the surgeon, less blood loss, a shorter hospital stay (2-3 days), and a quicker recovery.
Robotic-assisted laparoscopic radical prostatectomy
A further advancement in key-hole surgery is the development of a robotic system that enhances the visualization and precision of the procedure. This system replicates the surgeon’s hand movements with instruments that articulate in all dimensions and eliminate tremor, with a full 3D image of the anatomy.
Radiotherapy is the delivery of radiation beams at the prostate, aiming to destroy the cancerous cells, with minimal impact on surrounding normal structures (bladder, urethra and rectum). It can also be used in a palliative setting, directed at areas of cancer outside the prostate, eg for relief of bone pain due to cancer spread. Radiotherapy can be administered like an X-ray, by directing the beam from outside the body onto the prostate (external beam radiotherapy), or by inserting radioactive ‘seeds’ or needles into the prostate (brachytherapy). Following radiotherapy, the PSA slowly declines and is monitored to assess the success of treatment, although this can take up to 12-18 months.
High Intensity Focused Ultrasound (HIFU)
This technique involves destruction of prostate tissue by sound waves which are delivered via a rectal ultrasound probe. These high energy waves are focused onto the prostate to generate temperatures >80 degrees, killing exposed cells, and the areas being treated can be simultaneously viewed on a screen by the treating surgeon. At this stage it is most often used in patients who have recurrence following radiotherapy, or those not appropriate for surgery or radiotherapy as the success rates and long term effects are unknown.
This treatment is usually offered to patients in whom the cancer has spread beyond the prostate, eg to lymph glands or bone. Prostate cancer is partly driven by the male hormone, testosterone, which is made by the testicles. By stopping the production of testosterone, the cancer usually significantly shrinks in size throughout the body, and is held dormant for a period of time that may last many years. Ways to achieve this consist of either:
surgically removing the testicles (orchidectomy)
taking medications, or 3-6 monthly injections to ‘turn off’ the testicles
The effectiveness of treatment can be monitored by the PSA reading, which quickly drops in most patients. Side effects are those of a loss of the male hormone and are similar to the menopause experienced by women as they lose their female hormones. These may consist of fatigue, loss of libido, loss of erections, hot flushes, tender or enlarged breasts, loss of muscle bulk. Over time the bones may lose strength (osteoporosis) with increased risk of fracture, and therefore it is recommended to have regular bone density scans.
Hormonal therapy is not a cure, as with time the cancer begins to grow again despite the treatment, but is an effective control that in some patients can last for a long period of time.
Which treatment should I choose?
On top of the shock of being diagnosed with cancer, the array of possible treatment plans can leave patients feeling very confused as to which is most appropriate for them. Some patients feel surprised at being offered a choice of treatments and naturally feel inadequately prepared to make such an important decision. It is worthwhile seeking multiple consultations to discuss options, as well as second opinions from other specialists before coming to a decision.
Outcomes of Robotic Surgery
What are YOUR results? This is the question that all men should ask their surgeon when considering treatment options for prostate cancer. In addition to Dr Daniel Moon’s presented and published outcomes, he also contributes to the Victorian Prostate Cancer Registry, which can compare Victorian prostate cancer surgeons’ caseload and results.
The Victorian Prostate Cancer Registry has been independently collecting outcomes of men treated for prostate cancer since 2009. Over 8000 cases of prostate cancer have now been collected and the analysis is ongoing. Through quarterly reports outcomes can be reported by surgeon for:
Positive margin rates ie has the cancer been completely removed? This is a marker of the quality of surgery performed, and should be kept as low as possible.
Urinary bother suffered by men at 12 and 24 months post-operatively
Sexual bother suffered by men at 12 and 24 months post-operatively
The graphs below are an example of a quarterly report (February 2015), revealing the outcomes for all prostate cancer surgeons (the black dots) contributing to this registry, with Dr Daniel Moon highlighted as a red square, and a brown line representing the average result for Victorian patients in this study.