Diagnosing prostate cancer

Friday 1 April, 2016

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On this page:  Prostate specific antigen blood test | Digital rectal examination | Biopsy | Further tests | Staging and grading | Prognosis | Which health professionals will I see? | Key points


There is no single, simple test to detect prostate cancer. Two commonly used tests are the PSA blood test and the digital rectal examination. However these tests, used separately or in combination, can only indicate changes in the prostate gland. They are not diagnostic tests. If either test shows an abnormality, your GP will refer you to a urologist for further evaluation.

Prostate specific antigen (PSA) blood test

Prostate specific antigen (PSA) is a protein made by both normal prostate cells and cancerous prostate cells. PSA levels are measured using a blood test. The PSA test does not specifically test for cancer. A PSA reading above the typical range for your age may indicate the possibility of prostate cancer.

However, only an average of one in three men with an elevated PSA level has cancer4. The amount of PSA in blood can be raised even when a man does not have cancer. Other factors can increase PSA levels, including benign prostate hyperphasia (BPH), recent sexual activity or an infection in the prostate. In addition, some men with prostate cancer have normal PSA levels.

Because PSA levels can be variable, your doctor will often

use results from more than one blood test, over time, to help determine your risk of prostate cancer. Your doctor will also compare your PSA result against other men the same age as you.

Other tests your doctor may suggest include:

  • Free PSA test – Measures the PSA molecules in your blood that are not attached to other blood proteins (free PSA). This test may be suggested if your PSA score is moderately raised and your doctor is not sure if you need a biopsy. A low level of free PSA may indicate prostate cancer.
  • Prostate Health Index (PHI) – A blood test that measures three different forms of the PSA protein. This test is not widely used in Australia.

Digital rectal examination (DRE)

In a digital rectal examination (DRE) a doctor inserts a gloved finger into your rectum to feel the back of the prostate gland. The doctor feels the size of the prostate and checks for abnormalities. The DRE may be uncomfortable, but is rarely painful.

If your doctor feels a hardened area or an odd shape, further tests may be done. Abnormalities do not always indicate prostate cancer and a normal DRE does not rule out prostate cancer, as the test is unlikely to pick up a small cancer or one the finger can’t reach.

Digital rectal examination is no longer recommended as a routine test for men who do not have symptoms of prostate cancer. For men who wish to be tested for the presence of prostate cancer, the DRE is still useful. The test may help doctors assess the prostate prior to biopsy.

Biopsy

If the PSA test or DRE show an abnormality, a biopsy is often the next step. (Note: your doctor may suggest an mpMRI scan).

During a biopsy, small amounts of tissue are taken from different parts of the prostate using a special needle. The samples are sent to a lab where a pathologist examines the tissue to see whether cancer cells are present. Multiple tissue samples are taken so that the pathologist can indicate the extent of the tumour in the prostate.

A biopsy is usually done with the help of a transrectal ultrasound (TRUS) probe. The ultrasound shows the shape and size of the prostate on a screen. The image helps guide the doctor to insert a thin, hollow needle into the prostate. The TRUS probe is inserted through the rectum (transrectal biopsy) or the skin between the anus and the scrotum (transperineal biopsy). Transperineal biopsies may allow better sampling of the whole prostate and reduce the risk of infection. However the procedure takes longer, and is performed in an operating theatre under a general or regional anaesthetic.

A biopsy can be uncomfortable and for a few days there may be a small amount of blood in your urine, semen or bowel motions. You may be given antibiotics to reduce the possibility of infection.

Further tests

If the biopsy shows you have prostate cancer, other tests may be done to show the stage of the cancer. See below.

Blood tests

Blood samples may be taken regularly to monitor your PSA level, check your general health and determine prostate cancer activity.

Bone scan

This scan can show whether the cancer has spread to your bones. It can be used for later comparison if needed. A small amount of radioactive material (technetium) is injected into a vein. After 1–2 hours, you will have a body scan. This scan is painless.

CT scan

A CT (computerised tomography) scan uses x-ray beams to take pictures of the inside of your body. The scan can show whether cancer has spread to lymph nodes in the pelvis and abdomen.

A dye is injected into a vein, probably in your arm, to help make the scan pictures clearer. The dye may make you feel flushed or hot for a few minutes. You will lie still on a table that moves slowly through the CT scanner. The scanner is large and round like a doughnut. The CT scan itself takes a few minutes and is painless, but the preparation takes 10–30 minutes. You should be able to go home after their scan.

The dye that is injected into your veins before a CT scan may contain iodine, and may affect your kidneys. Tell your doctor if you have any allergies or kidney problems before your CT scan. You may need to have blood tests to check your kidney function.

MRI scan

An MRI (magnetic resonance imaging) scan uses a magnetic field to build up detailed cross-section pictures of the body. A dye may be injected into a vein during the scan to make the pictures clearer. You will lie on an examination table inside a magnetic cylinder that is open at both ends. The MRI is sometimes performed using a probe inserted into the rectum.

An MRI can help show whether the cancer has spread locally outside the prostate gland. This can help with management and treatment decisions. An MRI scan can be very noisy, and some people can feel claustrophobic while lying in the cylinder. Talk to your doctor or nurse before the scan if you feel anxious in confined spaces. You will not be able to have an MRI if you have a pacemaker or another iron-based metallic object in your body, because the scan may damage these devices.

Multi-parametric Magnetic Resonance Imaging (mpMRI)

This is a type of MRI scan in which three pulse sequences are used, with the results combined and analysed together. An mpMRI cannot diagnose prostate cancer, however if cancer is suspected, your doctor may recommend this test to identify which areas of the prostate may be abnormal. This may reduce the need for a biopsy.

At the time of publication, this test is not covered by Medicare and is available only at some hospitals. Ask your doctor for more information.

PET scans

These specialised scans are much more sensitive and specific in detecting recurrent or metastatic cancers. The prostate specific membrane antigen (PSMA) PET scan is the most commonly used. At time of publication, the scan is available in a few facilities in Australia. However, it is not available at all hospitals with PET facilities and there is no Medicare rebate.

Staging and grading

Your doctor will assign a staging and grading category to your cancer, which will help you and your health care team decide which treatment or management option is best for you.
Staging
Staging determines the extent of the cancer and whether it has spread from the original site to other parts of the body. The cancer may be described as one of the following:
  • Localised – the cancer is contained within the prostate.
  • Locally advanced – the cancer is larger and has spread outside the prostate to nearby tissues or organs near the prostate such as the bladder, rectum or pelvic wall.
  • Metastatic – the cancer has spread to distant parts of the body such as the lymph glands or bones, or secondary tumours have developed away from the primary tumour. This is called prostate cancer even if the tumour is in a different sort of tissue.
TNM system

This system is used to stage prostate cancer. Each letter is assigned a number that shows how advanced the cancer is. The lower the number, the less advanced the cancer. The scores are combined to describe the stage of the cancer from stage 1 to stage 4.

  • T (Tumour) 0–4: Refers to the extent of the primary tumour. The higher the number, the less likely the cancer is confined to the prostate gland.
  • N (Nodes) 0–3: Shows whether the cancer has spread to the regional lymph nodes near the bladder. No nodes affected is 0; increasing node involvement is 1, 2 or 3.
  • M (Metastasis) 0–1: Indicates whether the cancer has spread (metastasised) to the bones or other organs (1) or it hasn’t (0).
Grading

Grading describes how aggressive the cancer cells are. This is determined by a pathologist, who looks at the cells under a microscope. Low-grade cancer cells tend to grow slowly, while high-grade cancer cells look abnormal and grow more quickly. For many years, the Gleason scoring system has been used for grading the tissue taken during a biopsy. All men with prostate cancer will have a Gleason score between 6 and 10. Your doctor will also consider how much cancer there is (its volume). For example, if you have one small area of cancer, your doctor would consider this a low-volume cancer. If you have a low-volume cancer that is also low grade, you might choose to have less aggressive management or treatment such as active surveillance. From 2016, a new system will be gradually introduced. Called the International Society of Urological Pathology or ISUP score, this system grades cancer from 1 (least aggressive) to 5 (most aggressive).

Grading prostate cancer
Score
Gleason ISUP
Description
low
6 1 suggests a slow-growing, less aggressive cancer
intermediate
7
2-3 may indicate a faster- growing and moderately aggressive cancer
higher 8-10 4-5 indicates an aggressive cancer

Prognosis

Prognosis means the expected outcome of a disease. Generally, prognosis is better when prostate cancer is diagnosed while it is early stage, and at a lower grade.

You will need to discuss your prognosis with your doctor. However, it is not possible for any doctor to predict the exact course of the cancer. Test results, the extent of the spread of the cancer, and factors such as your age, level of fitness, medical and family history are important in assessing your prognosis. These factors will also help your doctor advise you on the best management or treatment options and tell you what to expect.

Prostate cancer often grows slowly and even the more aggressive prostate cancers tend to grow more slowly than other types of cancer. Compared with other cancers, prostate cancer has one of the highest five-year survival rates. For many men, the prostate cancer grows so slowly that it never needs treatment. Many men live with prostate cancer for many years without any symptoms and without it spreading.

Assessing risk of cancer progression

For men diagnosed with localised prostate cancer, risk of progression may be categorised as low, intermediate or high. The risk is determined by combining biopsy grading, clinical staging and pre-biopsy PSA along with overall health, age and wishes, to determine the most appropriate course of management or treatment.

Which health professionals will I see?

If your GP suspects you have prostate cancer, you may be referred to a urologist who can arrange further tests and advise you about your options. After a diagnosis of prostate cancer, you will be cared for by a range of health professionals who specialise in different aspects of your treatment. This multidisciplinary team (MDT) may include the following:

Specialist health professionals you might see
general practitioner (GP)  provides general health care and treatment, may also monitor PSA levels and administer treatment
urologist specialises in treating diseases of the urinary system and male reproductive system as well as performing prostate surgery and biopsies
radiation oncologist
specialises in prescribing and coordinating the course of radiotherapy
medical oncologist
specialises in treating cancer using drug treatments such as chemotherapy
endocrinologist specialises in hormones, body chemistry and bone density
cancer care coordinator/prostate cancer specialist nurse
supports patients throughout treatment and liaises with other care providers
oncology nurses
administer treatments and support and assist you through all stages of your management and/or treatment
continence nurses specialise in helping you manage continence (urinary and bowel) issues
urology care coordinator
supports patients who are experiencing bladder and bowel problems after cancer treatment
exervcise physiologist
assists people with medical conditions to exercise and improve their overall health, fitness, strength and energy levels
sexual health physician or sex therapist
can help you and your partner with sexuality issues before and after treatment
continence physiotherapist
provides exercises to help rehabilitate your pelvic floor muscles and improve continence
social worker, psychologist and counsellor
advise you on support services, provide emotional support and help manage depression and anxiety
occupational therapist
assists with physical rehabilitation and practical solutions for physical limitations
dietitian recommends an eating plan to follow while you’re in treatment and recovery
palliative care specialist
specialises in pain and symptom control to maximise wellbeing and improve quality of life

Key points

  • Your doctor may test the level of a protein called prostate specific antigen (PSA) in your blood. Some men with prostate cancer may have a higher PSA level, while a small proportion do not.
  • Your doctor may do a digital rectal examination (DRE) by inserting a gloved finger into your rectum to feel the prostate.
  • If tests show abnormalities, some tissue may be removed from the prostate for examination. This is called a biopsy.
  • MRI may be used to determine if a man needs a biopsy.
  • You may have other tests to determine the extent of the prostate cancer, including a bone scan, MRI scan or CT scan.
  • A specialist doctor such as a urologist will also assign a stage to the cancer. This describes how advanced the cancer is. The TNM (Tumour, Nodes, Metastasis) system is used for staging. The cancer may also be staged as localised, locally advanced, advanced or metastatic.
  • Diagnostic tests will provide information about the grade and volume of the cancer. The volume is how much cancer is in the prostate. The grade tells how fast the cancer may grow. Your doctor will describe the grade using the Gleason or ISUP score.
  • Your doctor may talk to you about the expected outcome of the disease, called your prognosis.
  • To determine the best form of management, men with localised prostate cancer are categorised as low, intermediate or high risk.

Reviewed by: A/Prof Nicholas Brook, Consultant Urological Surgeon, Royal Adelaide Hospital and Clinical Associate Professor in Surgery, University of Adelaide, SA; Prof Ian Davis, Professor of Medicine and Head of Eastern Health Clinical School, Monash University and Senior Oncologist, Eastern Health, VIC; A/Prof David Smith, Senior Research Fellow and Cancer Epidemiologist, Cancer Council NSW, NSW; A/Prof Peter Reaburn, Associate Professor in Exercise and Sport Sciences, CQU, QLD; Sylvia Burns, Senior Cancer Specialist, Cancer Council Queensland, QLD; Robyn Tucker, Clinical Nurse Specialist, Cancer Information and Support, Cancer Council Victoria, VIC.