Prostate cancer

Prostate cancer is the 6th most common cancer worldwide and the most common cancer (apart from skin cancers) in Australian men.

There are approximately 20,000 new diagnoses every year in this country and it is more common as men grow older. The incidence is very low until the age of 50 years at which point it increase. A man’s life time risk of developing the disease is around 16%. This increases in members of affected families, increasing with the number of affected first degree relatives (eg. brother, father) within a particular family:

• X1 first degree relative: 30%
• X2 first degree relatives: 50%
• X3 first degree relatives: almost 100%

Prostate cancer used to present at a late stage when men were bothered by urinary symptoms. However, since the introduction of PSA testing (a blood test to assess the risk of having the disease) the disease has been detected at a much earlier and more curable stage. The result of PSA testing has been to dramatically increase the numbers of patients detected with the disease. The problem with the widespread use of this test is that there are men who are diagnosed with what are termed indolent or latent cancers. These are small tumors that are unlikely to result in local problems (difficulty with the passage of urine) or result in cancer spread and death. If these men subsequently go on to have a prostate cancer treatment they are potentially being exposed to the complications of treatment with apparently little gain in terms of increasing life expectancy.

That being said there is a growing body of evidence in the surgical literature indicating that amongst populations were PSA screening is widespread there has been a reduction in the mortality rate from the disease.

At this stage there exists a relative grey area regarding the true merits of PSA testing and its correct place in the screening for prostate cancer but answers from large scale trials overseas will hopefully shed some more light on the issue in the near future.

What causes prostate cancer?

The exact answer to this question is still unknown. What we do know is that there is a large variation in the incidence of the disease worldwide and that there exists a significant difference amongst various ethnic groups. These variations suggest the following as possibilities as causative mechanisms in the development of prostate cancer:

1. Age: the disease is very uncommon in men under the age of 50 years. It becomes more common with age thereafter. Data from autopsy studies shows that up to 80% of men aged 80 years have evidence of the disease
2. Family history: The risk of the disease increases with the number of affected first degree relatives up to an almost 100% risk if there are 3 or more individuals within a family.
3. Ethnic origin: The lowest incidence in the world is amongst Asian men, however, after migration to countries where the incidence is higher, their incidence also increases. African American men have the highest incidence in the world and the highest age-specific mortality rate, suggesting that this ethnic group is prone to a more aggressive form of the disease
4. Diet: This is an area that is currently being extensively researched at the moment. There appears to be an increased risk with high intake of animal fat. It is also thought that high intake of soy products may be protective. Both selenium and vitamin E are thought to have a protective effect as are lycopenes which are responsible for the red colour in tomatoes. I general terms, a balanced healthy diet containing several daily portions of fruit and vegtables with limited intake of red meat is the most suitable.
5. Male sex hormones (testosterone): Some studies suggest that higher testosterone levels or changes in testosterone receptors may increase a man’s risk of the disease

Which treatment is best?

Treatment decisions for prostate cancer can be at best highly confusing! This in part is as a result of the many varied approaches possible, the varying forms of prostate cancer (or risk groups), the individual characteristics of a man’s prostate, his priorities in life and the expertise of the treating urologist.

It will obviously be a severe shock to be given a diagnosis of prostate cancer and it is important not to rush any decisions regarding treatment. Prostate cancer is different from many other cancers in that its behavior can range from slow growing through to an aggressive form. You and your urologist will be able to determine the risk group (type of cancer) of your disease by combining 3 characteristics: your PSA, Gleason score(what the cancer looked like under the microscope) and how the prostate gland felt when examined. 

Risk groups are: low, intermediate and high risk. The following table highlights the characteristics of each group:

The assignment of a risk group will give a rough guide to which treatment is possible and appropriate. It is then down to the patient with guidance from health care specialists to determine which treatment option is the most suitable for any man in question.

Active surveillance

For some men with small, low risk disease it may be reasonable to observe the cancer with serial PSA measurements (blood test) and periodic prostate biopsies to assess for any changes. The advantage of this treatment course is that is avoids the immediate potential complications of treatment with a view to deferring definitive treatment until there are signs of change. This form of treatment is called active surveillance.  The down side is that of regular review, blood tests and prostate biopsies combined with the potential anxiety of living with a diagnosis of prostate cancer. In addition, although there is some evidence in the surgical literature that this approach is safe in selected cases, there is no guarantee that the cancer will still be curable when definitive treatment is undertaken. The data from studies in North America show that around 30% of men who are surveyed for more than 12 months undergo progression and elect definitive treatment. Of those who had surgery 8% had incurable disease.

Surgery

Surgery for prostate cancer is called radical prostatectomy (RP). It can be performed in a variety of different ways including: open, perineal and recently laparoscopically (LRP) or robotically (RRP). The cure rate for localized disease treated in this way is in the order of 95% but varies with risk group.
Open RP is the traditional method of performing the surgery and has a proven track record. The main complications include urinary incontinence and erectile dysfunction (ED). The rates of both incontinence and erectile dysfunction vary from surgeon to surgeon and are also affected by the man’s age, other medical problems and the type of surgery performed (namely whether nerve sparing surgery was carried out). In specialized laparoscopic centers continence rates after LRP are around 95%.

When comparing the open approach with LRP the benefits for the laparoscopic approach include improved magnification, reduced blood loss, shorter hospital say and reduced convalescence. This approach has not yet become widespread in Australia in part due to the intensive training that is required to become proficient and training centers for this technique are located primarily in Europe where this technique was pioneered. The advantages of the robotic assisted approach are similar to those offered by laparoscopy but the down side is the additional cost to health care provider and to the patient.

Surgery is suitable for men with at least 10 years life expectancy and who have low or intermediate risk disease.

Radiotherapy

Radiation therapy can be delivered in a variety of different ways. It can be given as an external source (EBRT), or an internal source where radioactive seeds can be inserted into the prostate(low dose rate radiotherapy (LDR), or alternatively a combination of both internal radiation combined with external beam: this is called high dose rate radiotherapy(HDR).  These varying forms of radiotherapy are suitable for different risks groups.

LDR or seeds is a treatment option for men with low risk disease who have a small prostate, minimal urinary symptoms and at least 10 years of life expectancy. The advantage of this approach is the short hospital stay and the avoidance of any incisions (cuts in the skin). The disadvantage is a worsening of urinary function for 12-18 months. Potency may initially be preserved but can deteriorate over time. This is in contrast to surgery where potency in lost at the time of surgery and subsequently recovers following the operation.

HDR involves the placement of needles into the prostate whilst an in-patient in hospital. These are placed behind the scrotum into the prostate. Through these needles radioactive material is inserted to allow high doses of radiation to treat the prostate cancer. Three treatments are usually given whilst in hospital. Following discharge a course of external beam radiotherapy is then completed over several weeks. This form of treatment is suitable for older men with intermediate or high risk disease. It is combined with a course of hormone therapy. This most commonly is in the form of 1-3 monthly injections that aim to lower the body’s testosterone levels (male hormone). This is usually continued for 6 months.

Where can I get reliable information?

The Cancer Council Helpline 13 11 20
for information and support for you and your family.
www.cancer.org.au

Australian Prostate Cancer Collaboration
www.prostatehealth.org.au

Andrology Australia
www.andrologyaustralia.org