Diagnosing prostate cancer

Prostate specific antigen (PSA) blood test

Prostate specific antigen (PSA) is a protein made by both normal prostate cells and cancerous prostate cells. PSA is found in the blood and can be measured with a blood test. The test results will show the level of PSA in your blood as nanograms of PSA per millilitre (ng/mL) of blood.

There isn’t one normal PSA level for everyone. If your PSA level is above 3 ng/mL (called the threshold), this may be a sign of prostate cancer. But younger people or people who have a family history of prostate cancer may have a lower threshold. PSA levels can vary from day to day. If your PSA is higher than expected, your GP will usually repeat the test to help work out your risk of prostate cancer.

Your PSA level can be raised even when you don’t have cancer. Other common causes of raised PSA levels include benign prostate hyperplasia, recent sexual activity, an infection in the prostate, or a recent digital rectal examination. Some people with prostate cancer have normal PSA levels for their age range.

Free PSA or free-to-total test

Your doctor may also suggest that you have a free PSA test. This test measures the ratio of free PSA to total PSA in your blood. Free PSA is PSA that is not attached to other blood proteins. This test may be suggested if your PSA level is 4–10 ng/mL and your doctor is not sure whether you need a biopsy. A low free-to-total PSA ratio may be a sign of prostate cancer.

Digital rectal examination (DRE)

To do a digital rectal examination (DRE), the urologist places a finger into your rectum to feel the back of the prostate. They’ll wear gloves and put gel on their finger to make the examination more comfortable. 

You may have further tests if the doctor feels a hard area or an odd shape. These changes do not always mean you have prostate cancer. Having a normal DRE also does not rule out prostate cancer, as the finger can’t reach all of the prostate and a DRE is unlikely to feel a small cancer.

GPs no longer regularly do DRE, although it may still happen depending on your PSA results and urinary symptoms. A urologist will usually do a DRE as part of looking at your prostate. If your PSA is 3–10 ng/mL your doctor may suggest a DRE. If the DRE is normal and you have no symptoms, they may just do a repeat PSA test. If you are at high risk, they may suggest a urine biomarker test or MRI.

MRI scan

An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to build up detailed pictures of the inside of the body. A specialised MRI called mpMRI (multiparametric magnetic resonance imaging) is used if a doctor suspects prostate cancer. It combines the results of a number of MRI images to provide a more detailed image.

Your doctor may suggest an MRI to see if you need a biopsy or to guide the biopsy needle to a specific area of the prostate. It may also show if cancer has spread from the prostate to nearby areas.

Before the scan, let your medical team know if you have a pacemaker or any other metallic object in your body, as the magnet can interfere with some pacemakers. Newer pacemakers are often MRI-compatible.

Having an MRI

Sometimes a dye (called contrast) is injected into a vein before the scan to help make the pictures clearer. You will then lie on an examination table that slides into the scanner, which is a large metal cylinder open at both ends.

The scan is painless, but the scanner makes loud noises and is narrow, which makes some people feel anxious or claustrophobic. If you think you could become distressed, mention this beforehand to your medical team. You may be given a mild sedative to help you relax, or be able to bring someone into the room with you for support. You will have earplugs or headphones. The MRI scan may take around 30 minutes.

Biopsy

Depending on the results of the MRI scan, your urologist may suggest a biopsy to remove tissue samples from the prostate. They will explain the risks and benefits of a prostate biopsy and give you time to decide if you want to have one. With specialised MRI scans available, your doctor may suggest you do not need a biopsy.

There are 2 main ways to perform a prostate biopsy, both of which are normally done under general anaesthetic:

• transperineal (TPUS or TPB) biopsy – a small ultrasound probe is inserted into your rectum. An image of the prostate appears on a screen and helps guide a needle which is inserted through the skin between the anus and the scrotum
• transrectal (TRUS) biopsy – the needle is inserted into the prostate via the rectum. 

During either procedure, the doctor may take a number of samples from different areas of the prostate and also remove a sample from any suspicious areas seen on the MRI.

Side effects

Depending on the type of biopsy you have, after the procedure you may see a small amount of blood in your urine or bowel movements (poo) for a few days, and blood in your semen for a couple of months. After a TPUS biopsy, the risk of infection is extremely low. There is a greater risk of infection with a TRUS biopsy, but the risk is still low. Your doctor may suggest taking antibiotics before or after a biopsy if they think you may be at risk of infection.

The biopsy samples are sent to a laboratory, where a specialist doctor called a pathologist looks for cancer cells in the tissue. Waiting for the results can be stressful. For support, call Cancer Council 13 11 20.

Further tests

If the MRI or other biopsy results show prostate cancer, other tests may be done to work out whether the cancer has spread.

PSMA PET–CT scan

A PET (positron emission tomography) scan combined with a CT scan is a specialised imaging test. A PET–CT scan may be used to help detect cancers, or to find cancer that has spread or come back. The scan usually looks for a substance produced by prostate cancer cells called prostate specific membrane antigen (PSMA). Before the scan you will be injected with a small amount of a radioactive solution that makes PSMA show up on the scan. A Medicare rebate is available for newly diagnosed patients with intermediate or high-risk prostate cancer.

Bone scan

This scan can show if prostate cancer has spread to your bones. A tiny amount of radioactive dye is injected into a vein. You wait for a few hours while the dye moves through your bloodstream to your bones. The dye collects in areas of abnormal bone growth. Your body will then be scanned with a machine that detects the dye. A larger amount of dye will usually show up in any areas of bone with cancer cells. The scan is painless and the radioactive dye passes out of your body in a few hours.

CT scan

A CT (computerised tomography) scan uses x-rays to create detailed pictures of the inside of the body. A CT scan of the abdomen (belly) can show whether cancer has spread to lymph nodes in that area. A dye is injected into a vein to help make the scan pictures clearer. You will lie still on a table that moves slowly through the large, round doughnutshaped scanner. The scan itself takes a few minutes and is painless, but the preparation takes 10–30 minutes.

Which scan will I have? 

A large clinical trial conducted in Australia, the proPSMA trial, showed that for certain men with newly diagnosed prostate cancer, a PSMA PET–CT scan is more accurate than having traditional CT and bone scans. A Medicare rebate was introduced in 2022, meaning about 75% of all newly diagnosed prostate cancer patients in Australia will be offered a PSMA PET–CT instead of a CT and bone scan. 

Staging prostate cancer

The tests described above help your doctors work out if you have prostate cancer and whether it has spread. Working out how far the cancer has spread is called staging. It helps your doctors recommend the best treatment for you.

The most common staging system for prostate cancer is the TNM system. In this system, letters and numbers are used to describe the cancer, with higher numbers indicating larger size or spread.

Your doctor may also describe the cancer as:

• localised (early) – the cancer is contained inside the prostate
• locally advanced – the cancer is larger and has spread outside the prostate to nearby tissues or nearby organs such as the bladder, rectum or pelvic wall
• advanced (metastatic) – the cancer has spread to distant parts of the body such as the lymph nodes or bone. This is called prostate cancer even if the cancer is in a different part of the body.

Grading prostate cancer

The biopsy results will show the grade of the cancer. Grading describes how the cancer cells look under a microscope compared to normal cells.

For many years, the Gleason scoring system has been used to grade the tissue taken during a biopsy. If you have prostate cancer, you will have a Gleason score between 6 (slightly abnormal) and 10 (more abnormal). A newer system has been introduced to simplify the grading and make it easier to understand. Known as the International Society of Urological Pathologists (ISUP) Grade Group system, this grades prostate cancer from 1 (least aggressive) to 5 (most aggressive).

Risk of progression

Localised (early) prostate cancer is given a risk of progression that helps to guide treatment. The risk level is based on the size and grade of the cancer, and your PSA level before the biopsy (see table below):

Localised (early) prostate cancer risk level

Your PSA level and the tumour (T) size also help work out the cancer's risk level.

• low risk – slow growing and not aggressive
• intermediate risk – likely to grow faster and be mildly to moderately aggressive
• high risk – likely to grow quickly and be more aggressive.

Prognosis

Prognosis means the expected outcome of a disease. You can talk about your prognosis and treatment options with your doctor, but they can’t predict the exact course of the disease. They can give you an idea about the general outlook for people with the same type and stage of cancer.

To work out the stage, your doctor will consider your test results, the type of prostate cancer, the stage, grade and risk of progression, how well you respond to treatment, and your age, fitness and medical history.

Prostate cancer often grows slowly — even aggressive cases of prostate cancer tend to grow more slowly than other types of cancer. Some low-risk prostate cancers grow so slowly that they never cause any symptoms or spread; others don’t grow at all. Compared with other cancers, prostate cancer has one of the highest survival rates if diagnosed early.

After a diagnosis

Which health professionals will I see?

Your GP will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist, who will arrange further tests.

Prostate cancer is usually diagnosed by a urologist, who will talk to you about your surgical or other options. You will usually also see a radiation oncologist to discuss radiation therapy. You may also be referred to a medical oncologist, who will discuss drug treatments. It’s important to find out all your options before making a decision. 

Your specialists will discuss treatment options with other health professionals at what is known as a multidisciplinary team (MDT) meeting. During and after treatment, you will see a range of health professionals who specialise in different aspects of your care.

Health professionals you may see

Your treatment team willl include some of the following health professionsals:

GP: assists you with treatment decisions and works in partnership with your specialists in providing ongoing care; may monitor PSA levels and administer treatment

Urologist: treats diseases of the urinary system and the male reproductive system, including prostate cancer; performs surgery

Radiation oncologist: treats cancer by prescribing and overseeing a course of radiation therapy

Radiation therapist: plans and delivers radiation therapy

Medical oncologist: treats cancer with drug therapies such as chemotherapy, hormone therapy and targeted therapy (systemic treatment)

Endocrinologist: diagnoses, treats and manages hormonal disorders, including osteoporosis

Cancer care coordinator, prostate cancer specialist nurse: coordinate your care, liaise with MDT members, and support you throughout treatment; may be a clinical nurse consultant (CNC) or clinical nurse specialist (CNS)

Nurse: administers drugs and provides care, information and support throughout management or treatment

Nuclear medicine specialist: analyses bone scans and PET scans and delivers radionuclide therapies

Radiologist: analyses x-rays and scans; an interventional radiologist may also perform a biopsy guided by ultrasound or CT, and deliver some treatments

Pathologist: examines cells and tissue samples to determine the type and extent of the cancer

Continence nurse: assesses bladder and bowel control, and helps you find ways to manage any changes

Continence physiotherapist: provides exercises to help strengthen pelvic floor muscles and improve bladder and bowel control

Exercise physiologist: prescribes exercise to help people with medical conditions improve their overall health, fitness, strength and energy level

Occupational therapist: assists in adapting your living and working environment to help you resume your usual activities after treatment

Sex therapist, sexual health physician: help you and your partner with sexuality issues before and after treatment; an erectile dysfunction specialist can give advice about erection problems

Psychologist, counsellor, psychiatrist: help you manage your emotional response to diagnosis and treatment; may also help with emotional issues affecting sexuality

Aboriginal and Torres Strait Islander liaison officer: if you identify as Aboriginal or Torres Strait Islander, supports you and your family during treatment and recovery

Social worker: links you to support services and helps you with emotional, practical and financial issues

Palliative care specialists and nurses: work closely with your GP and cancer team to help control symptoms and maintain quality of life