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Prostate cancer - symptoms, diagnosis, treatment

 
Prostate cancer is the most commonly diagnosed cancer, and the third most common cause of cancer deaths, among New Zealand men. Around 1 in 10 New Zealand men will develop prostate cancer at some stage in their lifetime. This information sheet provides an overview of the prostate gland, and symptoms, diagnosis, treatment methods and screening related to prostate cancer.

Causes 

Each year in New Zealand approximately 3000 men are diagnosed with prostate cancer and approximately 600 men die from the disease; 80% of diagnoses are for men aged 60 years or more. The incidence of prostate cancer in New Zealand appears to be increasing.
 
The prostate gland, normally about 4 cm across, surrounds the neck of the bladder and the beginning of the urethra (the tube that drains urine from the bladder out through the penis).  Its main function is to produce semen, a fluid that protects and enriches sperm.
 

 Prostate cancer 1

Graphic courtesy of A. Bonsall and MedicineNet.com
 
Prostate cancer occurs when cells within the prostate gland become cancerous (malignant), forming a tumour.  When the cancer is contained within the prostate gland, this is referred to as "localised" prostate cancer.  When the cancer has spread to the tissues surrounding the prostate gland, this is referred to as "extracapsular" prostate cancer.  If the cancer cells spread to other parts of the body, this is referred to as "metastatic" prostate cancer.
 
The causes of prostate cancer are not fully understood.  However, it is known that the chances of developing the condition increase with age.  It is also known that prostate cancer is more common in men who have a history of prostate cancer in their family.  Other factors, such as smoking and dietary, hormonal and environmental influences (such as exposure to certain chemicals) may also increase the chances of developing the condition.  

Signs and symptoms

Prostate cancer frequently does not produce any symptoms until the condition is quite advanced.  Often it is diagnosed after treatment is sought for problems with urinary function.  Symptoms of prostate cancer are often similar to those of benign (non-cancerous) prostate conditions. Common symptoms include:

  • Decreased force of the urine stream
  • Pain and/or difficulty when passing urine
  • Passing urine more frequently (especially at night)
  • Blood in the urine
  • Inability to pass urine (this can occur as the cancer enlarges, blocking the urethra)
It is possible for the cancer cells to spread from the prostate gland to other areas of the body (metastasise) where further tumours can develop.  The most common places for prostate cancer to spread to are the lymph nodes of the pelvis and the bones of the spine. Spread of the cancer can produce symptoms such as lower back pain.

Diagnosis 

Common diagnostic tests for prostate cancer include:

Prostate specific antigen (PSA)
PSA is a protein produced by the prostate gland that can be detected in the blood.  Levels rise with age and when the prostate is enlarged. Significantly increased levels of PSA in the blood can indicate prostate cancer.  PSA levels are also known to rise in other prostate conditions such as prostatitis (inflammation of the prostate).  PSA is not a test for cancer in itself, but elevated levels require further assessment and investigation.
 
PSA Parameters:
AGE / PSA Value
Under 50 years / < 2.5
50 – 59 years / < 3.5
60 – 69 years / < 4.5
70 years and over / < 6.5
 
Digital Rectal Examination
A digital rectal examination involves the doctor placing a gloved finger into the rectum.  Through the wall of the rectum the doctor can feel the prostate gland and check for signs of enlargement or irregularity.  If any irregularity is found the doctor may recommend a biopsy.

Transrectal ultrasound biopsy (TRUS)
An ultrasound probe is inserted into the rectum and the prostate’s image is transmitted onto a television monitor, allowing any irregularities to be seen. A biopsy (tissue sample) is taken by inserting a needle into the prostate gland and withdrawing a small sample of tissue.  The needle is inserted via the rectum and the ultrasound is used to guide the needle to the correct biopsy location in the prostate gland.  It is usual for several biopsies to be taken from various locations in the prostate gland.  The biopsies are sent to a laboratory where they are examined under a microscope, making it possible to see if cancer cells are present. As there is a risk of infection following prostate biopsy, it is usual for antibiotics to be given prior to the procedure. Small amounts of blood may be present in the urine, semen or bowel movements following the biopsy.  Heavy bleeding is rare.  Where there have been repeated negative TRUS biopsy results, but the PSA remains elevated, a transperineal biopsy may be recommended. In this technique, the biopsy samples are obtained by inserting a needle into the prostate gland via the perineum (the area between the base of the penis and the anus). 

X-rays, CT/MRI and Bone Scans
If prostate cancer is confirmed, tests to assess whether the cancer has spread to other areas of the body may be recommended. This may include x-rays, a CT or MRI Scan and/or a bone scan.   MRI (magnetic resonance imaging) and CT (computerised tomography) are specialised scans that produce detailed cross-sectional images of the body.  MRI uses magnetic forces and radio waves to generate detailed images, whereas a CT scan uses computerised x-rays. Both scans allow bones and internal organs to be assessed for cancer spread.  The type of scan used will be determined by the treating doctor.  A bone scan (scintigraphy) involves injecting a radioisotope (a dye that emits a small amount of radiation) into the bloodstream through a drip in the hand or arm.  The dye travels around the body and will accumulate in any bony areas affected by the cancer.  Any deposits can then be detected with a specialised scanning machine.

Grading and staging 

Once a diagnosis of prostate cancer has been made it is important to determine the extent of the cancer.  The cancer is “graded” and “staged” using results of the diagnostic tests. 

Grading indicates the rate of growth (aggressiveness) of the tumour and staging indicates the spread and distribution of the cancer in the body.  The grade and stage of the tumour will determine what sort of treatment will be recommended.

The system used to grade prostate cancer is known as the Gleason Score.  This system assigns a grade of between 1 and 5 to the two most common cell patterns in the cancer, then adds the two grades together to provide the Gleason Score, which can range from 2 to 10.  The higher the score, the more aggressive the tumour is likely to be, and the greater the chance that it has spread within the body.  

The system used to stage prostate cancer is the TNM system.  The "T" refers to the extent of the tumour, the "N" refers to whether the lymph nodes are involved, and the "M" refers to whether cancer cells have spread (metastasised).

T Stages:
T1 - The tumour is confined to the prostate and is unable to be felt or seen on an ultrasound scan.
T2 - The tumour is confined to the prostate but can be felt and is able to be seen on an ultrasound scan.
T3 - The tumour has spread beyond the prostate.
T4 - The tumour has spread to the rectum, bladder or pelvic wall.

N Stages:
N0 - Cancer cells have not spread to regional lymph nodes.
N1 - Cancer cells have spread to regional lymph nodes.

M Stages:
M0 - There are no distant metastases.
M1 - Distant metastases are present.

Treatment 

The choice of treatment will differ for each individual.  A person’s age, general health, grade and stage of the cancer, symptoms, lifestyle and personal choice will all be taken into account.  It is important that time is taken to consider the treatment options available.  Treatment options include:

Watchful waiting
Prostate cancer is usually slow growing.  If no symptoms are present the doctor may recommend no treatment apart from regular PSA blood tests and monitoring.  This approach will be most suitable for low stage (T1-2, N0, M0), low grade prostate cancers.

Surgery
If the prostate cancer is causing a decreased urine flow or a complete blockage, surgery to relieve this may be required before any other treatment is undertaken.  Trans urethral resection of the prostate (TURP) is a surgical technique that allows blockages within the prostate gland to be removed.  This surgery involves inserting a telescope-like instrument (resectoscope) into the penis and up through the urethra, until it is positioned within the prostate gland.  A heated wire is inserted through the resectoscope and is used to remove excess prostate tissue that may be causing a blockage or restriction in urine flow.  Hospital stay after a TURP is usually 2-3 days.  In cases where the cancer has not spread beyond the prostate, surgical removal of the prostate gland may be recommended.  Known as a radical prostatectomy, it involves removal of the entire prostate gland and possibly also the adjacent lymph nodes.  It can be performed via an incision in the lower abdomen (retropubic approach) or via an incision in the perineal area (area between the scrotum and anus).  A hospital stay of 4 – 5 days following surgery is usual.  Urinary incontinence and erectile dysfunction are potential side effects of a radical prostatectomy.  Surgical techniques that avoid the nerves responsible for bladder control and sexual function ("nerve sparing" surgery) can help reduce the incidence of these side effects.

Radiotherapy
Radiotherapy is the controlled use of radiation to stop the growth of cancer cells. 

External beam:

Radiotherapy that is administered externally and is often referred to as external beam radiation.  A concentrated beam of radiation is aimed at the area over the prostate in order to destroy the cancer cells in the area.  This is usually given on a daily basis over a period of up to six weeks.  The treatment will be carefully planned so that damage to healthy tissue adjacent to the tumour is limited.  Side effects can occur but should resolve when the therapy has ended. Side effects of external beam radiation as a treatment for prostate cancer may include: 

  • Rectal bleeding
  • Urinary problems
  • Chronic diarrhoea
  • Impotence (erectile dysfunction)
  • Bowel dysfunction
  • Localized burning of the skin similar to severe sunburn
  • Fatigue
Prostate brachytherapy:
Another form of radiotherapy treatment for prostate cancer is prostate brachytherapy.  This technique uses radioactive seeds implanted directly into the prostate gland.  The radiation works in a localised area therefore decreasing the risk of damage to surrounding healthy tissue.  The benefits of this treatment include a short hospital stay (usually overnight), no major surgical wound and a speedy return to normal activities.  It is only suitable for treating cancers that have not spread beyond the prostate.  For more detailed information about prostate brachytherapy see our prostate brachytherapy article.

Hormonal treatment
When the cancer has spread beyond the prostate gland, hormone treatment may be recommended.  Testosterone, the main male sex hormone, stimulates the growth of prostate cancer cells.  Surgery or medications that have the effect of reducing the production of testosterone may be effective in slowing down or shrinking prostate cancer. 

As the testicles produce testosterone, an orchidectomy (the surgical removal of the testicles) may be recommended.  Possible side effects of an orchidectomy include decreased libido, impotence and hot flushes.

Alternatively, medications that block the effects of testosterone in the body (anti-androgen medications) may be recommended.  There are several different medications available and these may be given by injection or in tablet form.  Side effects of these medications may include fatigue, hot flushes, breast development, gastrointestinal upset, and abnormal liver function.

Chemotherapy
Chemotherapy is generally only used in cases of advanced metastatic prostate cancers that have failed to respond to other treatments.  Chemotherapy medications destroy cancer cells and are usually given by mouth (orally) or directly into the blood stream (intravenously). 

Screening for prostate cancer

There is debate as to the benefits of screening (regularly testing) men who do not have symptoms of prostate cancer.  While further studies are being completed as to the advantages/disadvantages of screening, patients should discuss the implications of being screened for prostate cancer with their doctor.

Support and information

The Prostate Cancer Foundation of New Zealand can provide patients, their families and friends with information and discuss options concerning prostate problems.   
Ph: 0800 PROSTATE (477 678)
Website: www.prostate.org.nz 

The Cancer Society of New Zealand operates a support and information phone service staffed by specialist nurses to help and support patients who may have been diagnosed with cancer, and their friends and families.
Ph: 0800 226 237
Website: www.cancernz.org.nz

References 

Cancer Society of New Zealand (2008) Prostate cancer: A guide for men with prostate cancer (Booklet). Wellington
Cancer Society of New Zealand (2011) Prostate Cancer (Information Sheet). Wellington
Cherath, L., Johnson, M. and Frey, R. J. (2005) Prostate cancer. The Gale Encyclopaedia of Cancer: A Guide to Cancer and Its Treatments. Second Edition. Jacqueline L. Longe, Editor. Farmington Hills, MI. Thompson Gale.
Cumming, A.D., Swainson, C.P. & Davidson, A.M. (1999) Diseases of the kidney and genito-urinary system. In C.R.W. Edwards, I.A.D. Bouchier, C.Haslett & E.R. Chilvers (eds.) Davidson’s principles and practice of medicine (18th ed.) (pp 611-667). Edinburgh: Churchill Livingstone
Gill, M. (ed.) (2000) PSA (prostate specific antigen) A handbook for the interpretation of laboratory tests (3rd ed.) (pg 331-333) Auckland: Diagnostic Medlab Ltd.
 
Last Reviewed – 15 November 2012
  

 

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