Prostate cancer is the most commonly diagnosed cancer, and the third most common cause of cancer deaths, among New Zealand men. Around one in eight men will develop prostate cancer at some stage in their lifetime. Prostate cancer that is found early has a better chance of successful treatment.
Each year in New Zealand approximately 4,000 men are diagnosed with prostate cancer and approximately 700 men die from the disease. The incidence of prostate cancer in New Zealand appears to be increasing.
The prostate is a walnut-shaped gland (normally about 4 cm across) located below the bladder. It surrounds 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 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 locally advanced or "extracapsular" prostate cancer. If the cancer cells spread (metastasise) to other parts of the body and produce new tumours, this is referred to as advanced or "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. Most cases of prostate cancer are in men aged 65 years or older. It is also known that prostate cancer is more common in men who have a history of prostate cancer in their family (a father or brother). 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
In many cases, prostate cancer 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, such as an enlarged prostate.
Common symptoms of prostate cancer 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 or semen
- Inability to pass urine (this can occur as the tumour enlarges, blocking the urethra).
The most common places in the body 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.
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), an enlarged prostate, or a prostate infection. PSA is not a test for cancer in itself. However, best practice guidelines are that abnormally high PSA levels indicate a need for further assessment and investigation.
Digital rectal examination (DRE)
DRE 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 ultrasound is used to guide the needle to the correct biopsy location in the prostate gland. The biopsy is sent to a laboratory where it is examined under a microscope, making it possible to see if cancer cells are present. Where there have been repeated negative TRUS biopsy results, but the PSA remains elevated, an ultrasound-guided transperineal prostate biopsy may be recommended. In this technique, the biopsy sample is obtained by inserting a needle into the prostate gland via the perineum (the area between the base of the penis and the anus). However, use of transperineal prostate biopsy is becoming more common because it can be performed as a same day procedure with a local (rather than general) anaesthetic and has a lower rate of post-procedure infection than transrectal ultrasound biopsy.
If prostate cancer is confirmed, imaging tests to assess whether the cancer has spread to other areas of the body may be recommended. This may include x-rays, a computerised tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, and/or a bone scan.
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 usually 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).
- 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.
- N0 - Cancer cells have not spread to nearby lymph nodes.
- N1 - Cancer cells have spread to nearby lymph nodes.
- M0 - There are no distant metastases.
- M1 - Distant metastases are present.
Instead of the TNM system, some doctors may talk about stages A, B, C and D or 1, 2, 3 and 4, respectively.
The choice of treatment will differ for each individual. The stage of the cancer, a person’s age, general health, symptoms, lifestyle, and personal choice will all be considered. It is important that time is taken to consider the treatment options available.
Recent guidance suggests that men should avail themselves of information about all treatment options, which may include consultations with both urologists and radiation oncologists where appropriate. Treatment options include:
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.
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) – 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.
- Radical prostatectomy – In cases where the cancer has not spread beyond the prostate, surgical removal of the prostate gland may be recommended. This procedure involves removal of the entire prostate gland and possibly also the adjacent lymph nodes. A hospital stay of 4–5 days following surgery is usual. Difficulty peeing (urinary incontinence) and getting an erection (erectile dysfunction), and infection 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.
Robotic-assisted radical prostatectomy – Similar to laparoscopic surgery but performed with more advanced instruments controlled using a robotic console, this makes the keyhole surgery easier to perform. Robotic surgery is only available in some private hospitals.
Radiotherapy (also called radiation therapy) is the controlled use of radiation to stop the growth of cancer cells. Two main types of radiotherapy are used for prostate cancer – external beam and brachytherapy.
- External beam – 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, including urinary problems, bowel dysfunction, and difficulty getting an erection, can occur but should resolve when the therapy has ended.
- Stereotactic Radiotherapy (SBRT) – This is similar to external beam radiotherapy but is a more intense and targeted radiation treatment that is delivered in fewer doses over about two weeks.
- 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 (androgen deprivation therapy)
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) or stop the body from producing testosterone (luteinizing hormone-releasing hormone medications) may be recommended. There are several different medications available, and these may be given by injection or in tablet form. Side effects of hormone therapy may include hot flushes, difficulty getting an erection, reduced sex drive, and loss of bone mass.
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).
Immunotherapy is a cancer treatment that uses a person’s own immune system to fight cancer. Although it is used in other types of cancer, immunotherapy for prostate cancer is still being researched and is currently only available through clinical trials.
Selective radioactive molecules (radioisotopes or radioligands) are injected into the bloodstream to target prostate cancer that has spread to other sites in the body. Targeted therapy may be available through some private clinics.
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 consider their risk factors (age, family history of prostate cancer, lifestyle factors) and discuss the implications of being screened for prostate cancer with their doctor.
Support and information
Prostate Cancer Foundation NZ
The Prostate Cancer Foundation of New Zealand can provide patients, their families and friends with information and discuss options concerning prostate problems.
Freephone: 0800 4 PROSTATE (0800 477 678)
Email: [email protected]
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.
Freephone: 0800 CANCER (0800 226 237)
Email: [email protected]
Kupe is a prostate cancer decision support tool designed to help men in their decision whether or not to get a prostate check.
Cancer Society (2019). Prostate cancer Matepukupuku repeure (Booklet). Auckland: Cancer Society of New Zealand. https://auckland-northland.cancernz.org.nz/assets/Uploads/Prostate-Cancer-Web-Booklet.pdf
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Mayo Clinic (2022). Prostate cancer screening: Should you get a PSA test? (Web Page). Rochester, MN: Mayo Foundation for Education and Research. https://www.mayoclinic.org/tests-procedures/psa-test/in-depth/prostate-cancer/art-20048087 [Accessed: 01/12/22]
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Ministry of Health (2013). Getting checked for prostate cancer (Pamphlet). Wellington: New Zealand Ministry of Health. https://www.healthed.govt.nz/system/files/resource-files/HE2400_Getting-checked-for-prostate-cancer-quick-guide.pdf
Ministry of Health (2015). Prostate cancer management and referral guidance (Booklet). Wellington: New Zealand Ministry of Health. https://www.health.govt.nz/system/files/documents/publications/prostate-cancer-management-referral-guidance_sept15-c.pdf
Prostate Cancer Foundation NZ (2022). Prostate cancer – what is it? (Web Page). Auckland: Prostate Cancer Foundation New Zealand. https://prostate.org.nz/prostate-cancer/ [Accessed: 01/12/22]
Last Reviewed: December 2022