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What is Prostate Cancer?The prostate is a gland found only in men. It surrounds the urethra (the tube

through the penis that drains urine from the bladder), and sits at the base of the

bladder. The prostate is normally about the size of a walnut.The function of the prostate is to produce fluid that forms part of the semen. This

prostatic fluid, in addition to the fluid produced by the seminal vesicles, forms the fluid

which carries the sperm when a man ejaculates. 

An adenocarcinoma is a type of  cancer that arises in the cells of glands. Most cells in the

prostate gland are of the glandular type, which means that adenocarcinoma is the most

common type of cancer to occur in the prostate. Cancer occurs when the genes of a cell

become abnormal (mutation), causing the cell to multiply and interfere with the normal

function of a tissue.

Once the cancer reaches a certain size, the abnormal cells can spread to other parts of the

body and cause cancerous tumours to grow. This phenomenon is known as metastasis. If 

a tumour is capable of spreading to other parts of the body in this way, it

is called malignant. Adenocarcinoma of the prostate is malignant, however many types

grow extremely slowly, and so are unlikely to spread before a man dies of other causes.

Statistics on Prostate CancerProstate cancer is the sixth most common cancer in the world and the most common form

of cancer in Australian men (after nonmelanoma skin cancer) who have the highest

incidence of this type of cancer in the world (105 cases per 100,000 males). One in six

men will develop prostate cancer at some point in their lives. Although prostate cancer is

the second most common cause of cancer in Indigenous Australian males (after lung

cancer), the rates are lower in Indigenous men than in non-Indigenous men. It is not clear

whether Indigenous Australians are truly less likely to develop prostate cancer, or

whether lower rates of screening and diagnostic testing as well as a shorter life

expectancy are contributing factors.

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There has been a significant increase in the rates of  diagnosed prostate cancer

since screening asymptomatic men became popular in the 1990s. This screening is

carried out via Prostate Specific Antigen (PSA) testing. 

The mean age at the time of prostate cancer diagnosis is 68.4 years and 85% of new casesoccur in men aged over 60.

 Following diagnosis, approximately 85% of men survive for 5

years or longer. Up to age 85, a quarter of Australian men will be diagnosed with prostate

cancer and 1 in 25 will die from it.

Statistics on Prostate Cancer

Prostate cancer is the sixth most common cancer in the world and the most common form

of cancer in Australian men (after nonmelanoma skin cancer) who have the highest

incidence of this type of cancer in the world (105 cases per 100,000 males). One in six

men will develop prostate cancer at some point in their lives. Although prostate cancer is

the second most common cause of cancer in Indigenous Australian males (after lung

cancer), the rates are lower in Indigenous men than in non-Indigenous men. It is not clear

whether Indigenous Australians are truly less likely to develop prostate cancer, or

whether lower rates of screening and diagnostic testing as well as a shorter life

expectancy are contributing factors.

There has been a significant increase in the rates of  diagnosed prostate cancer

since screening asymptomatic men became popular in the 1990s. This screening is

carried out via Prostate Specific Antigen (PSA) testing. 

The mean age at the time of prostate cancer diagnosis is 68.4 years and 85% of new cases

occur in men aged over 60. Following diagnosis, approximately 85% of men survive for 5

years or longer. Up to age 85, a quarter of Australian men will be diagnosed with prostate

cancer and 1 in 25 will die from it.

Risk Factors for Prostate CancerAge 

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The main risk factor for prostate cancer is age. Prostate cancer is rarely diagnosed before

the age of 40. After 40, the incidence rises rapidly. PSA testing is not generally carried

out on men aged under 50 unless they have significant risk factors. The rates of prostate

cancer at different ages are as follows:Age

(years)

Percentage of men

with prostate cancer

20 – 30 2 – 8%

31 – 40 9 – 31%

41 – 50 3 – 43%

51 – 60 5 – 46%

61 – 70 14 – 70%

71-80 31 – 83%

81 – 90 40 – 73%

Genetics 

Around 5 – 10% of prostate cancer is due to genetic defects, so men who have a family

history are more at risk of developing it themselves. Men who have a first degree relative(brother, father, son) who have had prostate cancer are two or three times more likely to

develop prostate cancer themselves. This risk may be higher if the relative was diagnosed

before the age of 60.

Identifying particular genes involved in prostate cancer has proved challenging.

The BRCA1 and BRCA2 genes are associated with having a two to five times higher risk 

of prostate cancer.

Race 

In American studies, Black men have higher rates of developing prostate cancer than

White or Hispanic men. Indigenous Australians are at lower risk of being diagnosed with

prostate cancer than White Australians.

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Lifestyle 

In Caucasians, smoking has been linked to a greater number of deaths due to prostate

cancer.Obesity may be linked with more aggressive forms of prostate cancer, but not with an

increased incidence. The link between prostate cancer and diet has been extensively

studied. Important findings include:

  A diet high in animal fat may contribute to prostate cancer;

  A diet low in vegetables may be a risk factor for prostate cancer; and

  Soy intake may have a modest protective effect against prostate cancer.

Other 

Other men who are at increased risk of prostate cancer are those who have had high PSA

levels, or abnormal prostatebiopsies in the past.

In the past, testosterone levels were thought to be related to the development of prostate

cancer, but this does not appear to be the case.

Progression of Prostate CancerIn many cases, prostate cancer spreads so slowly that it never causes illness, and the

patient will often die of other causes before the cancer can cause death. However, if the

cancer is left untreated, it is possible that it will spread to local pelvic lymph nodes, and

eventually spread to other parts of the body (metastasise). This may eventually result in

organ failure and death. Bony metastases  from prostate cancer are common. For men

who choose not to undergo definitive local treatment, their likelihood of survival relates

to the aggressiveness of the prostate cancer.

Without treatment, the 10 year disease-specific survival of men with grade 1 prostate

cancer (Gleason score 2 to 4) is 87%, with metastases present in 20%. Of men with grade

2 cancer, 42% develop metastases at 10 years. Ten year survival with grade 3 prostate

cancer (Gleason 5 to 7) is 34% without treatment.

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Another study found that 40% of men who did not have treatment for their prostate

cancer died from the disease after fifteen years. About 80% of men who chose radical

prostatectomy survived.

How is Prostate Cancer Treated?

Treatment options for prostate cancer include:

  Active surveillance 

  Local treatment 

o  Radical prostatectomy 

o  External beam radiotherapy 

o  Brachytherapy (internal radiotherapy) 

o  Hormonal therapy 

  Palliative treatments 

Active surveilance 

The risk of some small, non aggressive, localised prostate cancers ever spreading is verylow. In these cases, the risks of treatment may outweigh the benefits. A doctor may

therefore recommend 'watchful waiting', also known as 'active surveillance'.

In watchful waiting, the cancer and PSA levels are monitored, but no active treatment is

carried out. This may be particularly appropriate for men who have a life expectancy of 

less than 10 or 15 years, due to advanced age or other medical problems.

Local treatment 

If a man chooses to have treatment for prostate cancer, the main options in Australia

include surgery, radiotherapy and hormone therapy. There is no good quality evidence

that one approach is better than another, so treatment choice is based on the following

considerations:

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  Age, general medical condition and other medical problems. If a man has a life

expectancy of less than 10 years, definitive treatment may not be recommended.

  Serum PSA and Gleason score

  Spread of the cancer

  Outcomes associated with treatment options

  Side effects and quality of life implications related to treatment options

Radical prostatectomy 

Radical prostatectomy (RP) involves removing the prostate via a lower abdominal

incision, or via keyhole surgery (laparoscopic). RP generally involves a 4 – 8 day hospital

stay. A urinary catheter (tube through the penis into the bladder) with a urine bag

attached remains in place for at least 2 weeks after the operation. Death rates due to

radical prostatectomy are 0.5%, increasing to 1% in men over 75 years.

Sexual dysfunction may occur in 20 – 70% of patients following RP, and urinary problems

in 15 – 50%. Bilateral nerve sparing surgery may be possible in some cases. In some cases,

RP may be followed by radiotherapy.

Radiotherapy (External beam radiation therapy) 

External beam radiation therapy (EBRT) may be used with RP or hormonal therapy to

treat prostate cancer.

Beams of  radiation (like x-rays) are targeted at the prostate by a machine that moves

around the body. The rays kill the cancer cells. Small tattoos may be placed on the skin to

make sure the beam is in exactly the right place, and minimise damage to healthy tissue.

This procedure is performed in an out-patient setting, and men are usually able to

maintain their normal activities. Radiotherapy may lead to sexual dysfunction in 20 – 45%

of cases, urinary incontinence in 2 – 16%, and bowel dysfunction in 6 – 25% of men who

were previously normal in these areas.

For further information on EBRT, see  Radiotherapy for Prostate Cancer . 

Brachytherapy (Internal radiotherapy) 

There are two main types of  brachytherapy: 

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1.  Use of a radioactive pellet: This involves placing a small radioactive pellet into the

prostate (seeding). The pellet loses its radioactivity over time, and is not removed. This

option may be used for low Gleason score, low PSA, small, localised prostate cancer.

Side effects such as painful urination, poor urine flow and bladder irritation are common,

and can start a month after treatment; gradually getting better over 12 months.

2.  Use of wide bore needles: This type of brachytherapy involves inserting wide bore

needles into the prostate, through which radioactive sources can be given. After several

days of treatment, the needles are removed. This type of brachytherapy is used in

conjunction with EBRT for larger, more aggressive tumours. The needles may cause

local discomfort, usually relieved by painkillers. Other side effects are similar to those for

EBRT.

For further information on brachytherapy, see  Radiotherapy for Prostate Cancer . 

Hormonal therapy (Androgen deprivation therapy) 

Hormone therapy may be used in addition to EBRT. It is also used as palliative

treatment (i.e. treatment for prostate cancer that cannot be cured). Hormone therapy does

not improve outcomes when used before surgical treatment.

Testosterone appears to drive the growth of prostate cancer. Androgen deprivation

therapy (ADT) aims to lower levels of testosterone. This may be achieved by

removing the testes (often replaced with prosthetic testes) or medical castration with

drugs.

Side effects of ADT include hot flushes, loss of  libido, weight gain, erectile

dysfunction, gynaecomastia, fluid retention,osteoporosis and mood swings.

Palliative treatments Sometimes, prostate cancer is diagnosed and is too advanced to be cured by surgery or

radiotherapy. In these cases, treatment is referred to as 'palliative'. Palliative treatment is

designed to relieve symptoms, maintain quality of life and, in many cases, prolong life. It

will not cure the disease.

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  Transuretheral resection of the prostate (TURP) may be carried out to relieve obstructive

symptoms due to the cancer.

  Hormone therapy: ADT is a mainstay of treatment for cancer that is not resectable

(removable by surgery). Eventually, the cancer will no longer respond to ADT.

  Bisphosphonates and analgesia may be used to treat cancer spread to bones.

  EBRT may be used to treat pain related to bone metastases.

Relative side effects of different treatments: 

  Radical prostatectomy and brachytherapy result in higher rates of urinary incontinence

and sexual dysfunction than EBRT. Bilateral nerve sparing surgery (not possible in all

cases) diminishes this difference.

  RT causes more bowel dysfunction than surgery.

  Brachytherapy causes more obstructive and irritative urinary symptoms.

Treatment recommendations 

Good quality evidence of the best approach to prostate cancer is limited, but the

following treatment strategies have been suggested:

  Low-risk disease: Radical prostatectomy, brachytherapy monotherapy, or EBRT.

  Intermediate-risk disease: EBRT or surgery. The role of brachytherapy alone is

controversial. Brachytherapy plus EBRT may be superior to EBRT alone, though this is

also controversial.

  High-risk disease: Radical prostatectomy with or without adjuvant EBRT, or EBRT plus

ADT. EBRT or brachytherapy alone are not generally appropriate.